Updated on 2024/12/26

写真a

 
SAKO Yasuhito
 
Organization
School of Medicine Medical Course Basic Medicine Parasitology
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Degree

  • 博士(医学) ( 2011.3   旭川医科大学 )

  • 博士(獣医学) ( 1999.3   北海道大学 )

Research Interests

  • Parasitology

  • parasitology

  • molecular biology

  • infectious diseases

  • laboratory medicine

Research Areas

  • Life Science / Parasitology

  • Life Science / Infectious disease medicine

  • Environmental Science/Agriculture Science / Environmental impact assessment

Education

  • Hokkaido University   Graduate School, Division of Veterinary Medicine

    - 1999.3

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    Country: Japan

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  • Hokkaido University

    - 1999

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    Country: Japan

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  • Hokkaido University   Graduate School, Division of Veterinary Medicine

    - 1999

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  • Hokkaido University   Faculty of Veterinary Medicine   Veterinary Medicine

    - 1995.3

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    Country: Japan

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  • Hokkaido University   Faculty of Veterinary Medicine

    - 1995

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Professional Memberships

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Papers

  • Molecular identification of Spirometra infections in companion animals and wildlife in Japan. Reviewed

    Hiroshi Yamasaki, Hiromu Sugiyama, Yasuyuki Morishima, Yasuhito Sako

    The Journal of veterinary medical science   86 ( 4 )   409 - 412   2024.4

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    Spirometra infections in companion animals and wildlife in Japan have been diagnosed based on the morphology of the adult worms and eggs, and the etiological agent has been mainly ascribed to Spirometra erinaceieuropaei. However, recent studies have revealed that two other species, Spirometra mansoni and Spirometra asiana, coexist in Japan. Spirometra asiana is a new species recently discovered in Japan. Although morphological discrimination between these two species is difficult, molecular identification is useful. Therefore, to understand which species commonly parasitizes companion animals and wildlife in Japan, a preliminary study was performed based on mitochondrial DNA analysis. Eleven adult worms examined were identified as S. mansoni, suggesting that S. mansoni infects companion animals and wildlife commonly than S. asiana in Japan.

    DOI: 10.1292/jvms.23-0475

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  • Development and evaluation of an immunochromatography-based point-of-care test kit for a rapid diagnosis of human cysticercosis. Reviewed International journal

    Lakkhana Sadaow, Patcharaporn Boonroumkaew, Rutchanee Rodpai, Penchom Janwan, Oranuch Sanpool, Tongjit Thanchomnang, Yasuyuki Morishima, Marcello Otake Sato, Yasuhito Sako, Kaoru Kobayashi, Misako Iwai, Wanchai Maleewong, Hiroshi Yamasaki, Pewpan M Intapan

    Food and waterborne parasitology   33   e00211   2023.12

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    Human cysticercosis is a life-threatening zoonotic disease caused by infection with larvae (cysticerci) of the pork tapeworm, Taenia solium. This can affect the nervous system causing chronic headache and intracranial hypertension, potentially leading to epileptic seizures and paralysis. The disease is found in developing countries, especially in Southeast and South Asia, Sub-Saharan Africa, and Central and South America where porcine cysticercosis is endemic and people have a habit of eating undercooked pork. An immunochromatography-based test (ICT) kit, using T. solium cyst fluid as antigen, was manufactured to detect anti-T. solium IgG antibodies in human serum. To evaluate the kit, we used 187 serum samples including 24 from proven/confirmed cysticercosis cases, 133 from cases with other parasitosis and 30 healthy controls. Diagnostic efficiencies were calculated. The sensitivity, specificity, and accuracy were 83.3%, 92.0%, and 90.9%, respectively. Moreover, the ICT was positive before treatment but became negative after treatment, implying that this kit is also useful for follow-up monitoring post-treatment. In conclusion, we have successfully developed and present preliminary evaluation of an easy-to-handle rapid diagnostic tool for human cysticercosis in the form of an ICT platform using as antigen fluid from T. solium cysticerci.

    DOI: 10.1016/j.fawpar.2023.e00211

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  • Dibothriocephalus nihonkaiensis incidentally detected at colonoscopy. Reviewed

    Kubo K., Kato M., Sako Y.

    Clin Gastroenterol Hepatol   2022.1

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  • Origin of the pork tapeworm Taenia solium in Bali and Papua, Indonesia. Reviewed International journal

    Tetsuya Yanagida, Kadek Swastika, Nyoman Sadra Dharmawan, Yasuhito Sako, Toni Wandra, Akira Ito, Munehiro Okamoto

    Parasitology international   83   102285 - 102285   2021.8

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    Global distributions of zoonotic pathogens have been strongly affected by the history of human dispersal and domestication of livestock. The pork tapeworm Taenia solium is distributed worldwide as the cause of neurocysticercosis, one of the most serious neglected tropical diseases. T. solium has been reported in Indonesia but only endemic to restricted areas such as Bali and Papua. Previous studies indicated the distinctiveness of a mitochondrial haplotype confirmed in Papua, but only one isolate has been examined to date. In this study, genetic characterization of T. solium and pigs in Bali and Papua was conducted to clarify the distributional history of the parasite. Mitochondrial haplotype network analysis clearly showed that Indonesian T. solium comprises a unique haplogroup which was the first to diverge among Asian genotypes, indicating its single origin and the fact that it was not introduced in the recent past from other area in Asia in which it is endemic. Although phylogenetic analysis based on the mitochondrial D-loop revealed multiple origins of pigs in Bali and Papua, the majority of pigs belonged to the Pacific Clade, which is widely dispersed throughout the Island Southeast Asia (ISEA) and Oceania due to Neolithic human dispersal. Given the results of our network analysis, it is likely that the Pacific Clade pigs played a key role in the dispersal of T. solium. The data suggest that T. solium was introduced from mainland Asia into Western Indonesia, including Bali, by modern humans in the late Pleistocene, or in the early to middle Holocene along with the Pacific Clade pigs. Introduction into New Guinea most likely occurred in the late Holocene through the spread of Pacific Clade pigs. Over time, T. solium has been eradicated from most of Indonesia through the middle to modern ages owing to religious and cultural practices.

    DOI: 10.1016/j.parint.2021.102285

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  • 日本海裂頭条虫感染の1症例報告

    工藤裕基, 畠山真奈美, 仲山春恵, 迫康仁

    臨床検査学教育   11 ( 1 )   121 - 122   2019

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  • Taenia solium, Taenia saginata, Taenia asiatica, their hybrids and other helminthic infections occurring in a neglected tropical diseases' highly endemic area in Lao PDR Reviewed

    Marcello Otake Sato, Megumi Sato, Tetsuya Yanagida, Jitra Waikagul, Tiengkham Pongvongsa, Yasuhito Sako, Surapol Sanguankiat, Tipparayat Yoonuan, Sengchanh Kounnavang, Satoru Kawai, Akira Ito, Munehiro Okamoto, Kazuhiko Moji

    PLoS Neglected Tropical Diseases   12 ( 2 )   2018.2

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    Most part of Southeast Asia is considered endemic for human-infecting Taenia tapeworms
    Taenia solium, T. saginata, and T. asiatica. However, until now there was no report of the occurrence of human cases of T. asiatica in Lao PDR. This study, conducted in Savannakhet Province, Lao PDR, microscopically examined a total of 470 fecal samples by Kato Katz method and found 86% of people harboring at least one helminth. Hookworms were detected in 56% of the samples besides Opisthorchis like eggs (42%), Trichuris trichiura (27%), Ascaris spp. (14%), and Taenia spp. (4%) eggs. Serology for cysticercosis showed 6.8% positives with results varying from 3% to 14.3% in Ethnic School students and Kalouk Kao village respectively. Species-specific PCR targeting mitochondrial DNA (mtDNA) of 28 tapeworms, recovered from 16 patients, revealed T. solium (n = 2), T. saginata (n = 21), and T. asiatica (n = 5). Two patients were confirmed to be coinfected with T. saginata and T. asiatica, indicating the endemicity of the 3 human Taenia in Lao PDR. However, nucleotide sequencing of a nuclear DNA gene, DNA polymerase delta (pold) revealed that all the tapeworms identified as T. asiatica using mtDNA had T. saginata type allele at pold locus, demonstrating that they are not “pure T. asiatica” but the hybrid descendants between the two species, confirming the wide distribution of hybrids of T. saginata/ T. asiatica in Southeast Asia. The high prevalence of several helminthic NTDs in east Savannakhet area even with conventional control measures indicates the importance to establish wide and multifaceted health programs to sustainably improve the quality of life of the populations living in these communities.

    DOI: 10.1371/journal.pntd.0006260

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  • Genetic and morphological characterization of Thysaniezia tapeworms from cattle and sheep in Senegal. Reviewed International journal

    Mallé Ndom, Tetsuya Yanagida, Gora Diop, Yann Quilichini, Aïssatou Ba, Yasuhito Sako, Minoru Nakao, Bernard Marchand, Alioune Dieye, Cheikh Tidiane Ba, Akira Ito

    Veterinary parasitology, regional studies and reports   11   27 - 31   2018.1

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    Genetic and morphological diversity of Thysaniezia tapeworms from cattle and sheep in Senegal was investigated using light and scanning microscopic observations and molecular analysis based on mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear small subunit ribosomal RNA gene (SSU rDNA). A total of 52 adult tapeworms were collected from sheep and cattle. Although the tapeworms of the two hosts were morphologically very close, phylogenetic analysis based on cox1 and SSU rDNA gene sequences showed that they were divided into two clades corresponding each to a host. The maximum pairwise divergence between the clades were 12.1% in cox1 and 2.9% in SSU rDNA, indicating they are distinct species. The tapeworms collected from sheep were morphologically identified as Thysaniezia ovilla, a cosmopolitan species in domestic ruminants. Detailed morphological observations revealed a consistent difference between the tapeworms obtained from sheep and those from cattle. The latter were identified as Thysaniezia connochaeti. The present study highlights presence of two species of Thysaniezia among domestic ruminants in Senegal: T. ovilla specific to sheep and T. connochaeti specific to cattle. Our work is the first report of T. connochaeti from domestic animals.

    DOI: 10.1016/j.vprsr.2017.11.008

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  • Co-occurrence of swine cysticercosis due to Taenia solium and Taenia hydatigena in ethnic minority villages at the Thai-Myanmar border Reviewed

    Chaisiri K., Kusolsuk T., Homsuwan N., Sanguankiat S., Dekumyoy P., Peunpipoom G., Khiriphattharaphon S., Sako Y., Yanagida T., Okamoto M., Ito A.

    Journal of Helminthology   1 - 9   2018

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  • Seroprevalence and risk factors of human cysticercosis and taeniasis prevalence in a highly endemic area of epilepsy in Bangoua, west Cameroon Reviewed

    Agathe Nkouawa, Armel Romeo Dschanou, Roger Moyou-Somo, Yasuhito Sako, Akira Ito

    ACTA TROPICA   165   116 - 120   2017.1

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    Cysticercosis caused by the larvae of Taenia solium is a serious and emerging threat to public health in the endemic areas as well as in the non-endemic areas. Neurocysticercosis, an affection of the central nervous system is a leading cause of epilepsy in endemic areas. This study was carried out to investigate human cysticercosis, taeniasis and risk factors, and also their association with epilepsy in Bangoua, west Cameroon where epilepsy is highly prevalent. Out of 384 people investigated, 12 (3.1%) exhibited antibody response against low molecular weight antigens of T. solium by ELISA. Immunoblot revealed that six persons (1.6%) were seropositive with the same antigens. Among 61 epileptic patients, only one was seropositive by immunoblot and the study did not find any statistically significant difference (P > 0.05) in seropositivity to T. solium between epileptic persons (1/61, 1.6%) and non-epileptic group (5/323, 1.5%). In addition, cysticercosis was associated with households eating pork meat from pigs slaughtered at home, but not with other factors. The risk factors including pig farming, the consumption of pork meat, vegetables, and non-drinkable water were attenuated by the relatively good hygiene and pig husbandry practices of the population. No egg of Taenia was found in stool by microscopic examination. All data obtained in this study suggested that cysticercosis might not be the principal causative agent of epilepsy in this area. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.actatropica.2015.12.019

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  • The putative serine protease inhibitor (serpin) genes encoded on Echinococcus multilocularis genome and their expressions in metacestodal stage Reviewed

    Mizuki Sasaki, Yasuhito Sako

    VETERINARY PARASITOLOGY   233   20 - 24   2017.1

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    Two putative serpin genes were identified in Echinococcus multilocularis, in addition to the already reported serpinEmu, and were designated as serpin2Emu and serpin3Emu. Western blot analysis using polyclonal antibodies against serpinEmu, putative serpin2Emu protein, and putative serpin3Emu protein indicated that all three proteins were localized in both intracellular and excretory-secretory (ES) fractions of E. multilocularis metacestodes. In addition, immune staining of parasite tissue indicated that all three proteins were localized at the germinal layer. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.vetpar.2016.11.019

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  • Serological validation of an alveolar echinococcosis rat model with a single hepatic lesion Reviewed

    Yamashita M., Imagawa T., Sako Y., Okamoto M., Yanagida T., Okamoto Y., Tsuka T., Osaki T., Ito A.

    Journal of Veterinary Medicine and Science   79   308 - 313   2017

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    DOI: 10.1292/jvms.16-0513

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  • Swine cysticercosis in the Karangasem district of Bali, Indonesia: An evaluation of serological screening methods Reviewed

    Kadek Swastika, Nyoman Sadra Dharmawan, I. Ketut Suardita, I. Nengah Kepeng, Toni Wandra, Yasuhito Sako, Munehiro Okamoto, Tetsuya Yanagida, Mizuki Sasaki, Patrick Giraudoux, Minoru Nakao, Takahiko Yoshida, Luh Putu Eka Diarthini, I. Made Sudarmaja, Ivan Elisabeth Purba, Christine M. Budke, Akira Ito

    ACTA TROPICA   163   46 - 53   2016.11

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    A serological assessment was undertaken on pigs from the Kubu and Abang sub-districts of Karangasem on the island of Bali, Indonesia, where earlier studies had detected patients with cysticercosis. Antigens purified from Taeniasolium cyst fluid by cation-exchange chromatography were used to evaluate antibody responses in the pigs and the serological tests were also evaluated using sera from pigs experimentally infected with T. solium eggs. A total of 392 serum samples from naturally exposed pigs were tested using an ELISA that could be read based on both a colour change perceptible by the naked eye and an ELISA based on absorbance values. Twenty six (6.6%) pigs were found seropositive by the naked-eye ELISA and were categorized into three groups: strongly positive (absorbance values >0.8, n = 6), moderately positive (absorbance values between 0.2 and 0.8, n = 7), and weakly positive (absorbance values <0.2, n = 13). Necropsies performed on 11 strongly and moderately positive pigs revealed that six strongly positive pigs were infected either solely with T. solium cysticerci (n = 3), or co-infected with both T. solium and Taenia hydatigena (n = 3). Four moderately positive pigs were infected solely with T. hydatigena. No cysticerci were found in one pig that was moderately positive by the naked-eye ELISA. Two experimentally infected pigs became antibody positive by 6 weeks post-infection, whereas eight control pigs remained negative. An additional 60 pigs slaughtered at authorized abattoirs on Bali were tested using the same ELISA. All 60 pigs were seronegative with no evidence of Taenia infection at necropsy. The results confirm the presence of porcine cysticercosis on Bali and, while the serological responses seen in T. solium infected animals were much stronger than those infected with T. hydatigena, the diagnostic antigens are clearly not species specific. Further studies are necessary to confirm if it is possible to draw a cut off line for differentiation of pig infected with T. solium from those infected with T. hydatigena. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.actatropica.2016.07.022

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  • Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay Reviewed

    Agathe Nkouawa, Yasuhito Sako, Munehiro Okamoto, Akira Ito

    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE   94 ( 6 )   1318 - 1323   2016.6

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    For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T solium, T saginata, and T asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical.

    DOI: 10.4269/ajtmh.15-0829

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  • Genetic characterization of Moniezia species in Senegal and Ethiopia. Reviewed International journal

    Gora Diop, Tetsuya Yanagida, Zerihun Hailemariam, Sissay Menkir, Minoru Nakao, Yasuhito Sako, Cheikh Tidiane Ba, Akira Ito

    Parasitology international   64 ( 5 )   256 - 60   2015.10

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    Genetic diversity of Moniezia spp. from domestic ruminants in Senegal and Ethiopia was investigated based on the nucleotide sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear small subunit ribosomal RNA gene (SSU rDNA). A total of 64 adult tapeworms were collected from sheep, goat and cattle, and the tapeworms from cattle were all morphologically identified as Moniezia benedeni. On the other hand, the tapeworms obtained from sheep and goat were identified as Moniezia expansa or could not be identified because of the lack of diagnostic morphologic character, i.e. interproglottidal glands (IPGs). Phylogenetic analysis based on cox1 gene sequences revealed that the worms from sheep/goat and cattle formed distinct clades, and three mitochondrial lineages were confirmed within the sheep/goat tapeworms. The maximum pairwise divergences among the three mitochondrial linages were about 3% in cox1 and 0.1% in SSU rDNA, while that between the worms from sheep/goat and cattle reached 13% in cox1 and 2.7% in SSU rDNA. All of the three mitochondrial lineages contained tapeworms morphologically identified as M. expansa, and the tapeworms without IPGs were confirmed in one of the three lineages, indicating the tapeworms without IPGs were also M. expansa.

    DOI: 10.1016/j.parint.2015.02.008

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  • Comparative Study of Paired Serum and Cerebrospinal Fluid Samples from Neurocysticercosis Patients for the Detection of Specific Antibody to Taenia solium Immunodiagnostic Antigen. Reviewed

    Yasuhito Sako, Osvaldo M Takayanagui, Newton S Odashima, Akira Ito

    Tropical medicine and health   43 ( 3 )   171 - 6   2015.9

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    Neurocysticercosis (NCC) is an important disease of the central nervous system caused by infection with Taenia solium metacestodes. In addition to the clinical findings and the imaging analysis, the results of immunological tests are informative for the diagnosis of NCC. To compare the usefulness of serum and cerebrospinal fluid (CSF) samples for antibody detection, paired serum and CSF samples from patients with NCC and other neurological diseases were examined by an enzyme-linked immunosorbent assay with low-molecular-weight antigens purified from T. solium cyst fluid in a blinded fashion. The sensitivity of both serum and CSF samples was 25.0% in inactive NCC cases (n = 4) and 90.9% in active NCC cases (n = 33), and the specificity of serum and CSF was 100% and 95.8%, respectively. When the serum and CSF samples were combined, the sensitivity in active NCC cases became 100%. There was no difference in test performance between serum and CSF samples. Based on these results, we recommend the detection of specific antibodies in serum for the diagnosis of active NCC because of the ease of collection. When the antibody test is negative, however, CSF should be used to confirm NCC and to rule out other medical disorders of the central nervous system. Antibody detection test using only serum or CSF has a limited diagnostic value and cannot be recommended for the diagnosis of suspected inactive NCC cases.

    DOI: 10.2149/tmh.2015-04

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  • The present situation and towards the prevention and control of neurocysticercosis on the tropical island, Bali, Indonesia. Reviewed International journal

    Toni Wandra, Kadek Swastika, Nyoman S Dharmawan, Ivan Elisabeth Purba, I Made Sudarmaja, Takahiko Yoshida, Yasuhito Sako, Munehiro Okamoto, Ni Luh Putu Eka Diarthini, Dewa Ayu Agus Sri Laksemi, Tetsuya Yanagida, Minoru Nakao, Akira Ito

    Parasites & vectors   8   148 - 148   2015.3

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    Neurocysticercosis (NCC), which is caused by accidental ingestion of eggs of the pork tapeworm, Taenia solium, was common in Bali, Indonesia until the early 1990s. However, improved education on hygiene and sanitation, a move to keeping pigs indoors, and improvement of economic and living conditions have substantially reduced the occurrence of NCC in Bali. Since 2011, T. solium tapeworm carriers (T. solium taeniasis) and heavily infected pigs and dogs have exclusively been detected from villages in mountainous regions of northeastern Bali where NCC and ocular cysticercosis (OCC) cases have also been identified. In response to this continued area of high infection, a one-day workshop was convened to discuss how to prevent and control this potentially lethal zoonotic parasitic infection in Bali. This review presents an overview of the current status of T. solium taeniasis and cysticercosis in Indonesia and proposes a strategy for the prevention and control of this zoonosis in Bali.

    DOI: 10.1186/s13071-015-0755-z

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  • Evaluation of a New Immunochromatographic Test Using Recombinant Antigen B8/1 for Diagnosis of Cystic Echinococcosis. Reviewed

    Santivanez SJ, Rodriguez ML, Rodriguez S., Sako Y., Nkouawa A., Kobayashi Y., Sotomayor AL, Peralta JE, Valcarcel M., Gonzalez AE, Garcia HH, Ito A.

    Journal of Clinical Microbiology   2015

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    DOI: 10.1128/JCM.02157-15

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  • Cystic Echinococcoses in Mongolia: Molecular Identification, Serology and Risk Factors Reviewed

    Akira Ito, Temuulen Dorjsuren, Anu Davaasuren, Tetsuya Yanagida, Yasuhito Sako, Kazuhiro Nakaya, Minoru Nakao, Oyun-Erdene Bat-Ochir, Tsendjav Ayushkhuu, Narantuya Bazarragchaa, Nyamkhuu Gonchigsengee, Tiaoying Li, Gurbadam Agvaandaram, Abmed Davaajav, Chinchuluun Boldbaatar, Gantigmaa Chuluunbaatar

    PLOS NEGLECTED TROPICAL DISEASES   8 ( 6 )   2014.6

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    Background: Cystic echinococcosis (CE) is a globally distributed cestode zoonosis that causes hepatic cysts. Although Echinococcus granulosus sensu stricto (s.s.) is the major causative agent of CE worldwide, recent molecular epidemiological studies have revealed that E. canadensis is common in countries where camels are present. One such country is Mongolia.
    Methodology/Principal Findings: Forty-three human hepatic CE cases that were confirmed histopathologically at the National Center of Pathology (NCP) in Ulaanbaatar (UB) were identified by analysis of mitochondrial cox 1 gene as being caused by either E. canadensis (n = 31, 72.1%) or E. granulosus s.s. (n = 12, 27.9%). The majority of the E. canadensis cases were strain G6/7 (29/31, 93.5%). Twenty three haplotypes were identified. Sixteen of 39 CE cases with data on age, sex and province of residence were citizens of UB (41.0%), with 13 of the 16 cases from UB caused by E. canadensis (G6/7) (81.3%). Among these 13 cases, nine were children (69.2%). All pediatric cases (n = 18) were due to E. canadensis with 17 of the 18 cases (94.4%) due to strain G6/7. Serum samples were available for 31 of the 43 CE cases, with 22 (71.0%) samples positive by ELISA to recombinant Antigen B8/1 (rAgB). Nine of 10 CE cases caused by E. granulosus s.s. (90.0%) and 13 of 20 CE cases by E. canadensis (G6/7) (65.0%) were seropositive. The one CE case caused by E. canadensis (G10) was seronegative. CE cases caused by E. granulosus s.s. showed higher absorbance values (median value 1.131) than those caused by E. canadensis (G6/7) (median value 0.106) (p = 0.0137).
    Conclusion/Significance: The main species/strains in the study population were E. canadenis and E. granulossus s.s. with E. canadensis the predominant species identified in children. The reason why E. canadensis appears to be so common in children is unknown.

    DOI: 10.1371/journal.pntd.0002937

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  • Recent situation of taeniasis in Mongolia (2002-2012). Reviewed International journal

    Anu Davaasuren, Temuulen Dorjsuren, Tetsuya Yanagida, Yasuhito Sako, Kazuhiro Nakaya, Abmed Davaajav, Gurbadam Agvaandaram, Tsatsral Enkhbat, Battsetseg Gonchigoo, Nyamkhuu Dulmaa, Gantigmaa Chuluunbaatar, Akira Ito

    The Korean journal of parasitology   52 ( 2 )   211 - 4   2014.4

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    Epidemiological situation of taeniasis in Mongolia was assessed based on mitochondrial DNA identification of the parasite species. Multiplex PCR was used on a total of 194 proglottid specimens of Taenia species and copro-PCR and loop-mediated isothermal amplification (LAMP) assays were utilized for detection of copro-DNA of 37 fecal samples from taeniasis patients submitted to the Mongolian National Center for Communicable Diseases (NCCD) from 2002 to 2012. In addition, 4 out of 44 calcified cysts in beef kept in formalin since 2003 were evaluated for histopathological confirmation of cattle cysticercosis. All proglottid specimens and stool samples were confirmed to be Taenia saginata by multiplex PCR and by copro-PCR and LAMP, respectively. Cysts collected from cattle were morphologically confirmed to be metacestodes of Taenia species. T. saginata taeniasis was identified from almost all ages from a 2-year-old boy up to a 88-year-old woman and most prominently in 15-29 age group (37%, 74/198) followed by 30-44 age group (34.8%, 69/198 ) from 15 of Mongolia's 21 provinces, while cattle cysticerci were found from 12 provinces. The highest proportion of taeniasis patients was in Ulaanbaatar, the capital of Mongolia.

    DOI: 10.3347/kjp.2014.52.2.211

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  • A survey of seropositivity to antigen B, an immunodiagnostic antigen for human cystic echinococcosis, in domestic animals in Mongolia. Reviewed

    Chinchuluun B., Sako Y., Khatanbaatar I., Bayarmaa B., Lkhagvatseren S., Battsetseg G., Yanagida T., Itoh S., Temuulen D., Budke CM, Ito A., Batsukh Z.

    Parasitol Int   63 ( 2 )   324 - 328   2014

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    DOI: 10.1016/j.parint.2013.12.002

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  • Genetics of the pig tapeworm in madagascar reveal a history of human dispersal and colonization. Reviewed International journal

    Tetsuya Yanagida, Jean-François Carod, Yasuhito Sako, Minoru Nakao, Eric P Hoberg, Akira Ito

    PloS one   9 ( 10 )   e109002   2014

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    An intricate history of human dispersal and geographic colonization has strongly affected the distribution of human pathogens. The pig tapeworm Taenia solium occurs throughout the world as the causative agent of cysticercosis, one of the most serious neglected tropical diseases. Discrete genetic lineages of T. solium in Asia and Africa/Latin America are geographically disjunct; only in Madagascar are they sympatric. Linguistic, archaeological and genetic evidence has indicated that the people in Madagascar have mixed ancestry from Island Southeast Asia and East Africa. Hence, anthropogenic introduction of the tapeworm from Southeast Asia and Africa had been postulated. This study shows that the major mitochondrial haplotype of T. solium in Madagascar is closely related to those from the Indian Subcontinent. Parasitological evidence presented here, and human genetics previously reported, support the hypothesis of an Indian influence on Malagasy culture coinciding with periods of early human migration onto the island. We also found evidence of nuclear-mitochondrial discordance in single tapeworms, indicating unexpected cross-fertilization between the two lineages of T. solium. Analyses of genetic and geographic populations of T. solium in Madagascar will shed light on apparently rapid evolution of this organism driven by recent (<2,000 yr) human migrations, following tens of thousands of years of geographic isolation.

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  • Comparison of the serological tests ICT and ELISA for the diagnosis of alveolar echinococcosis in France. Reviewed International journal

    Jenny Knapp, Yasuhito Sako, Frédéric Grenouillet, Solange Bresson-Hadni, Carine Richou, Houssein Gbaguidi-Haore, Akira Ito, Laurence Millon

    Parasite (Paris, France)   21   34 - 34   2014

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    Serological diagnosis of alveolar echinococcosis (AE) is a key element for efficient patient treatment management. A rapid immunochromatography test kit (ICT) using the recombinant Em18 antigen (rEm18) was recently developed. The aim of our study was to assess this test on a panel of sera from French patients with alveolar echinococcosis and control patients. In a blind test, a total of 112 serum samples were tested including samples of AE (n = 30), cystic echinococcosis [CE] (n = 15), and polycystic echinococcosis [PE] (n = 1). For the comparison, 66 sera from patients with hepatocarcinoma, fascioliasis, toxocariasis, Caroli's disease, or autoimmune chronic active hepatitis were used. The diagnostic test sets we used were the rEm18-ICT and two validated ELISAs with rEm18 and Em2-Em18 antigens, respectively. For the ICT, 27/30 sera from AE patients, 4/15 sera from CE patients and the PE patient serum were positive. One serum from the control panel (toxocariasis) was positive for the ICT. The rEm18-ICT sensitivity (90.0%) and specificity (92.7%) for detection of Em18-specific antibodies confirmed it as a relevant tool for AE diagnosis. The rEm18-ELISA had a sensitivity of 86.7% and specificity of 91.5%, and the Em2-Em18-ELISA had a sensitivity of 96.7% and specificity of 87.8%. However, when AE patient sera are recorded as weak in intensity with the ICT, we recommend a double reading and use of a reference sample if the ICT is used for patient follow-up.

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  • Immunodiagnosis of alveolar echinococcosis using urine samples Reviewed

    Makoto Itoh, Yasuhito Sako, Sonoyo Itoh, Yuji Ishikawa, Hiromitsu Akabane, Kazuhiro Nakaya, Fumiaki Nagaoka, Akira Ito

    PARASITOLOGY INTERNATIONAL   62 ( 6 )   514 - 516   2013.12

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    Alveolar echinococcosis (AE) is one of the most lethal zoonotic parasitic infections. The diagnosis is based on the combination of the abdominal imaging including CT, MRI and PET, and serology. To develop a new diagnostic tool for AE with urine as samples, mouse-Echinococcus multilocularis (Em) model and then human cases were studied. The antibody levels of urine and serum samples from the infected mice and AE cases were well correlated with each other. The sensitivity and specificity of the method with urine were 91% and 98%, respectively, when IgG4 to crude Em was examined. Comparing with serum samples, the collection of urine is easier and safer and the-urine diagnostic tool makes surveys of this silent disease easier. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

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  • Detection of human taeniases in Tibetan endemic areas, China Reviewed

    Tiaoying Li, Xingwang Chen, Tetsuya Yanagida, Hao Wang, Changping Long, Yasuhito Sako, Munehiro Okamoto, Yunfei Wu, Patrick Giraudoux, Francis Raoul, Agathe Nkouawa, Minoru Nakao, Philip S. Craig, Akira Ito

    PARASITOLOGY   140 ( 13 )   1602 - 1607   2013.11

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    Detection of taeniasis carriers of Taenia solium is essential for control of cysticercosis in humans and pigs. In the current study, we assessed the positive detection rate of a self-detection tool, stool microscopy with direct smear and coproPCR for taeniasis carriers in endemic Tibetan areas of northwest Sichuan. The self-detection tool through questioning about a history of proglottid expulsion within the previous one year showed an overall positive detection rate of more than 80% for Taenia saginata, T. solium and T. asiatica. The positive detection rate was similar for T. saginata and T. solium. In 132 taeniid tapeworm carriers, 68 (51.5%) were detected by microscopy and 92 (69.7%) were diagnosed by coproPCR. A combination of microscopy and coproPCR increased the positive detection rate to 77.3%. There remained 10 cases (7.6%) coproPCR negative but microscopy positive. Due to the high cost and complicated process, coproPCR is required for the identification of Taenia species only when necessary, though it had a significant higher positive detection rate than microscopy. Combined use of self-detection and stool microscopy are recommended in community-based mass screening for taeniases in this Tibetan area or in other situation-similar endemic regions.

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  • Echinococcus species from red foxes, corsac foxes, and wolves in Mongolia Reviewed

    Akira Ito, Gantigmaa Chuluunbaatar, Tetsuya Yanagida, Anu Davaasuren, Battulga Sumiya, Mitsuhiko Asakawa, Toshiaki Ki, Kazuhiro Nakaya, Abmed Davaajav, Temuulen Dorjsuren, Minoru Nakao, Yasuhito Sako

    PARASITOLOGY   140 ( 13 )   1648 - 1654   2013.11

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    The small intestines of 420 wild canids (111 corsac foxes, 191 red foxes and 118 wolves) from Mongolia, were examined for adult worms of the genus Echinococcus. The Mongolian genotype of Echinococcus multilocularis was found in fifteen red foxes and four wolves, whereas two genotypes (G6/7 and G10) of Echinococcus canadensis were found in two and three wolves, respectively. No adult Echinococcus worms were found in the corsac foxes examined. The genotypes of E. multilocularis and E. canadensis are discussed in terms of host specificity and distribution in Mongolia. The importance of wolves in the completion of the life cycle of Echinococcus spp. is also discussed.

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  • Genotypic relationships between taenia saginata, taenia asiatica and their hybrids Reviewed

    Kanako Yamane, Tetsuya Yanagida, Tiaoying Li, Xingwang Chen, Paron Dekumyoy, Jitra Waikagul, Agathe Nkouawa, Minoru Nakao, Yasuhito Sako, Akira Ito, Hiroshi Sato, Munehiro Okamoto

    Parasitology   140 ( 13 )   1595 - 1601   2013.11

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    SUMMARY Partial sequences of the DNA polymerase delta (pold) gene from Taenia saginata-like adult worms were sequenced. Phylogenetic analysis revealed that pold gene sequences were clearly divided into two clades, differing from each other in five to seven nucleotides. There is little doubt that T. saginata and Taenia asiatica were once separated into two distinct taxa as has been concluded in previous studies. On the other hand, most of the adult worms, which were identified as T. asiatica using mitochondrial DNA, were homozygous for an allele that originated from the allele of T. saginata via single nucleotide substitution. These results indicate that most of the adult worms, which had been called T. asiatica, are not actually 'pure T. asiatica' but instead originated from the hybridization of 'pure T. saginata' and 'pure T. asiatica'. © 2013 Cambridge University Press.

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  • Simple and reliable preparation of immunodiagnostic antigens for taenia solium cysticercosis Reviewed

    Y. Sako, S. Itoh, M. Okamoto, K. Nakaya, A. Ito

    Parasitology   140 ( 13 )   1589 - 1594   2013.11

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  • Genetic diversity of Echinococcus spp. in Russia Reviewed

    Sergey V. Konyaev, Tetsuya Yanagida, Minoru Nakao, Galina M. Ingovatova, Yakov N. Shoykhet, Alexandr Y. Bondarev, Valeriy A. Odnokurtsev, Kyunnyay S. Loskutova, Gulnur I. Lukmanova, Nikolai E. Dokuchaev, Sergey Spiridonov, Mikhail V. Alshinecky, Tatyana N. Sivkova, Oleg N. Andreyanov, Sergey A. Abramov, Anton V. Krivopalov, Sergey V. Karpenko, Natalia V. Lopatina, Tamara A. Dupal, Yasuhito Sako, Akira Ito

    PARASITOLOGY   140 ( 13 )   1637 - 1647   2013.11

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    In Russia, both alveolar and cystic echinococcoses are endemic. This study aimed to identify the aetiological agents of the diseases and to investigate the distribution of each Echinococcus species in Russia. A total of 75 Echinococcus specimens were collected from 14 host species from 2010 to 2012. Based on the mitochondrial DNA sequences, they were identified as Echinococcus granulosus sensu stricto (s.s.), E. canadensis and E. multilocularis. E. granulosus s.s. was confirmed in the European Russia and the Altai region. Three genotypes, G6, G8 and G10 of E. canadensis were detected in Yakutia. G6 was also found in the Altai region. Four genotypes of E. multilocularis were confirmed; the Asian genotype in the western Siberia and the European Russia, the Mongolian genotype in an island of Baikal Lake and the Altai Republic, the European genotype from a captive monkey in Moscow Zoo and the North American genotype in Yakutia. The present distributional record will become a basis of public health to control echinococcoses in Russia. The rich genetic diversity demonstrates the importance of Russia in investigating the evolutionary history of the genus Echinococcus.

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  • Serological and Molecular Characteristics of the First Korean Case of Echinococcus multilocularis Reviewed

    Jin-Sook Jeong, Sang-Young Han, Young-Hoon Kim, Yasuhito Sako, Tetsuya Yanagida, Akira Ito, Jong-Yil Chai

    KOREAN JOURNAL OF PARASITOLOGY   51 ( 5 )   595 - 597   2013.10

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    In December 2011, we reported an autochthonous case of Echinococcus multilocularis infection in a 42-year-old woman in Korea. The diagnosis was based on histopathological findings of the surgically resected liver cyst. In the present study, we evaluated the serological and molecular characteristics of this Korean E multilocularis case. The patient's serum strongly reacted with affinity-purified native Em18 and recombinant Em18 antigens (specific for E. multilocularis) but negative for recombinant antigen B8/1 (reactive for Echinococcus granulosus). In immunoaffinity chromatography, the serum also strongly reacted with E. multilocularis and only weakly positive for E granulosus. We determined the whole nucleotide sequence of cox1 (1,608 bp) using the paraffin-embedded cystic tissue which was compared with E. multilocularis isolates from China, Japan, Kazakhstan, Austria, France, and Slovakia. The Korean case showed 99.8-99.9% similarity with isolates from Asia (the highest similarity with an isolate from Sichuan, China), whereas the similarity with European isolates ranged from 99.5 to 99.6%.

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  • Case Report: Rare Case of Disseminated Cysticercosis and Taeniasis in a Japanese Traveler after Returning from India Reviewed

    Ken-ichiro Kobayashi, Fukumi Nakamura-Uchiyama, Takeshi Nishiguchi, Kenichi Isoda, Yasumasa Kokubo, Katsuhiko Ando, Masaki Katurahara, Yasuhito Sako, Tetsuya Yanagida, Akira Ito, Sentaro Iwabuchi, Kenji Ohnishi

    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE   89 ( 1 )   58 - 62   2013.7

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    We report disseminated cysticercosis concurrent with taeniasis in a 31-year-old male Japanese, who had visited India three times and stayed for 1 month each time during the previous 1 year. The patient presented increasing numbers of subcutaneous nodules and expelled proglottids, although numerous cysts were also found in the brain in imaging findings, though no neurological symptoms were observed. Histopathological and serological findings strongly indicated cysticercosis. We found taeniid eggs in his stool by microscopic examination and revealed them as the Indian haplotype of Taenia solium by mitochondrial DNA analysis. We concluded that disseminated cysticercosis was caused by the secondary autoinfection with eggs released from the tapeworm carrier himself. After confirming the absence of adult worms in the intestine by copro-polymerase chain reaction, the patient was successfully treated with albendazole at a dose of 15 mg/kg/day for 28 days. Subcutaneous and intracranial lesions had completely disappeared by the end of the treatment period.

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  • Mini review on chemotherapy of taeniasis and cysticercosis due to Taenia solium in Asia, and a case report with 20 tapeworms in China. Reviewed

    Ito A., Li T., Chen X., Long C., Yanagida T., Nakao M., Sako Y., Okamoto M., Wu Y., Raoul F., Giraudoux P., Craig PS

    Trop Biomed   30 ( 2 )   164 - 173   2013

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  • Recombinant AgB8/1 ELISA test vs. commercially available IgG ELISA test in the diagnosis of cystic echinococcosis. Reviewed

    Tamarozzi F., Sako Y., Ito A., Piccoli L., Grisolia A., Itoh S., Gatti S., Meroni V., Genco F., Brunetti E.

    Parasite Immunol   2013

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  • Advances in diagnosis and spatial analysis of cysticercosis and taeniasis. Reviewed

    Raoul F., Li T., Sako Y., Chen X., Long C., Yanagida T., Wu Y., Nakao M., Okamoto M., Craig PS, Giraudoux P., Ito A.

    Parasitology   140 ( 13 )   1578 - 1588   2013

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  • Loop-mediated isothermal amplification method for a differential identification of human taenia tapeworms Reviewed

    Yasuhito Sako, Agathe Nkouawa, Tetsuya Yanagida, Akira Ito

    Methods in Molecular Biology   1039   109 - 120   2013

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    Loop-mediated isothermal amplification (LAMP), which employs a Bst DNA polymerase with strand-displacement activity and four primers (two inner primers and two outer primers) recognizing six distinct regions on the target DNA, is a highly sensitive, specific, simple, and rapid nucleotide amplification method. Moreover, because the Bst DNA polymerase resists much DNA polymerase inhibitors present in biological specimens, the LAMP method is suitable for the detection of infectious agents from clinical material such as fecal samples. Here, we describe the LAMP method which can differentially detect and identify human Taenia tapeworms, Taenia solium, T. saginata, and T. asiatica, using DNA specimens prepared from parasite tissue and human fecal sample. © 2013 Springer Science+Business Media, New York.

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  • Taeniases and cysticercosis in Indonesia: past and present situations. Reviewed

    Wandra T., Ito A., Swastika K., Dharmawan NS, Sako Y., Okamoto M.

    Parasitology   140 ( 13 )   1608 - 1616   2013

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  • A loop-mediated isothermal amplification method for a differential identification of Taenia tapeworms from human: Application to a field survey Reviewed

    Agathe Nkouawa, Yasuhito Sako, Tiaoying Li, Xingwang Chen, Minoru Nakao, Tetsuya Yanagida, Munehiro Okamoto, Patrick Giraudoux, Francis Raoul, Kazuhiro Nakaya, Ning Xiao, Jiamin Qiu, Dongchuan Qiu, Philip S. Craig, Akira Ito

    PARASITOLOGY INTERNATIONAL   61 ( 4 )   723 - 725   2012.12

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    In this study, we applied a loop-mediated isothermal amplification method for identification of human Taenia tapeworms in Tibetan communities in Sichuan, China. Out of 51 proglottids recovered from 35 carriers, 9, 1, and 41 samples were identified as Taenia solium, Taenia asiatica and Taenia saginata, respectively. Same results were obtained afterwards in the laboratory, except one sample. These results demonstrated that the LAMP method enabled rapid identification of parasites in the field surveys, which suggested that this method would contribute to the control of Taenia infections in endemic areas. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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  • Genetic polymorphisms of Echinococcus granulosus sensu stricto in the Middle East Reviewed

    Tetsuya Yanagida, Tahereh Mohammadzadeh, Shaden Kamhawi, Minoru Nakao, Seyed Mahmoud Sadjjadi, Nawal Hijjawi, Sami K. Abdel-Hafez, Yasuhito Sako, Munehiro Okamoto, Akira Ito

    PARASITOLOGY INTERNATIONAL   61 ( 4 )   599 - 603   2012.12

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    Echinococcus granulosus sensu stricto is a cosmopolitan parasite causing cystic echinococcosis in humans and livestock. Recent molecular phylogeographic studies suggested the rapid dispersal of the parasite by the anthropogenic movement of domestic animal hosts. In the present study, genetic polymorphism of E. granulosus s. s. in the Middle East, where the domestication started, was investigated to validate the dispersal history of the parasite. Thirty-five and 26 hydatid cysts were collected from Iran and Jordan, respectively, and mitochondrial cytochrome c oxidase subunit I (cox 1) gene was sequenced. Chinese and Peruvian specimens were also analyzed for comparison. Haplotype network analysis demonstrated the existence of a common haplotype EG01 in all populations. Although EGO1 and its one-step neighbors were the majority in all regions, most of the neighboring haplotypes were unique in each locality. Haplotype diversity was high but nucleotide diversity was low in Iran, Jordan and China. Both diversities were lowest and only a few haplotypes were found in Peru. Neutrality indices were significantly negative in Iran, Jordan and China, and positive but not significant in Peru. Pairwise fixation index was significant for all pairwise comparisons, indicating genetic differentiation among populations. These results suggest a evolutionary history of E. granulosus s. s. in which a genetic subgroup including EGO1 was selected at the dawn of domestication, and then it was rapidly dispersed worldwide through the diffusion of stock raising. To approach the origin of the ancestral strain, extensive sampling is needed in many endemic regions. To evaluate the hypothetical evolutionary scenario, further study is needed to analyze specimens from diverse host species in wider regions. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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  • Molecular identification of human echinococcosis in the Altai region of Russia Reviewed

    Sergey V. Konyaev, Tetsuya Yanagida, Galina M. Ingovatova, Yakov N. Shoikhet, Minoru Nakao, Yasuhito Sako, Alexandr Y. Bondarev, Akira Ito

    PARASITOLOGY INTERNATIONAL   61 ( 4 )   711 - 714   2012.12

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    Mitochondrial haplotypes were determined for Echinococcus species infecting individuals diagnosed with alveolar echinococcosis (AE) and cystic echinococcosis (CE) at Altai State Medical University Hospital in Barnaul, Russia during 2008 to 2011. The nucleotide sequence of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was determined for 31 of 34 AE and 8 of 12 CE cases. All of the AE cases were confirmed to be caused by Asian type Echinococcus multilocularis, while CE cases were caused by Echinococcus granulosus sensu stricto (genotype G1) and Echinococcus canadensis (genotype G6). (c) 2012 Elsevier Ireland Ltd. All rights reserved.

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  • The first report on cystic echinococcosis in a cat caused by Echinococcus granulosus sensu stricto (G1) Reviewed

    S. V. Konyaev, T. Yanagida, M. V. Ivanov, V. V. Ruppel, Y. Sako, M. Nakao, A. Ito

    JOURNAL OF HELMINTHOLOGY   86 ( 4 )   391 - 394   2012.12

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    A case of cystic echinococcosis (CE) in a domestic cat is described from Saint Petersburg, Russia. Ultrasonography showed numerous cysts with hyperechoic walls and anechoic contents within the cat's abdominal cavity. Molecular identification based on mitochondrial DNA genes indicated that the causative agent was Echinococcus granulosus sensu stricto (G1 strain). This is the first report of CE in a cat caused by E. granulosus sensu stricto with molecular confirmation.

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  • Usefulness of pumpkin seeds combined with areca nut extract in community-based treatment of human taeniasis in northwest Sichuan Province, China. Reviewed

    Li T., Ito A., Chen X., Long C., Okamoto M., Raoul F., Giraudoux P., Yanagida T., Nakao M., Sako Y., Xiao N., Craig PS

    Acta Trop   124 ( 2 )   152 - 157   2012.10

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  • Comparison of the usefulness of hydatid cyst fluid, native antigen B and recombinant antigen B8/1 for serological diagnosis of cystic echinococcosis. Reviewed

    Mohammadzadeh T., Sako Y., Sadjjadi SM, Sarkari B., Ito A.

    Trans R Soc Trop Med Hyg   106   371 - 375   2012.6

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  • An ocular cysticercosis in Bali, Indonesia caused by Taenia solium Asian genotype. Reviewed

    Swastika K., Dewiyani CI, Yanagida T., Sako Y., Sudarmaja M., Sutisna P., Wandra T., Dharmawan NS, Nakaya K., Okamoto M., Ito A.

    Parasitol Int   61 ( 2 )   378 - 380   2012.6

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  • Recent hybridization between Taenia asiatica and Taenia saginata Reviewed

    Kanako Yamane, Yumi Suzuki, Eiko Tachi, Tiaoying Li, Xingwang Chen, Minoru Nakao, Agathe Nkouawa, Testuya Yanagida, Yasuhito Sako, Akira Ito, Hiroshi Sato, Munehiro Okamoto

    PARASITOLOGY INTERNATIONAL   61 ( 2 )   351 - 355   2012.6

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    Five Taenia tapeworms collected from humans in Tibetan Plateau, Sichuan, China, where three species of human Taeina are sympatrically endemic, were examined for the mitochondrial cox1 gene and two nuclear genes, ef1 and elp. Phylogenetic analyses of these genes revealed that two adult worms showed nuclear-mitochondrial discordance, suggesting that they originated from hybridization between Taenia saginata and Taenia asiatica. One of two worms had T. asiatica-type mtDNA, whereas another worm had T. saginata-type mtDNA, indicating that reciprocal hybridization between T. saginata and T. asiatica could occur. The worm having T. asiatica-type mtDNA was heterozygous at both nuclear loci with T. saginata-type alleles and T. asiatica-type alleles. In another worm, the ef1 locus was heterozygous with a T. saginata-type alleles and T. asiatica-type alleles, while the elp locus was homozygous with T. saginata-type alleles. Self-fertilization is the main reproductive method of the genus Taenia. Since self-fertilization represents a type of inbreeding, each locus in the offspring would become homozygous over generations with genetic drift. The fact that some nuclear loci are still heterozygous means that hybridization might have occurred recently. Hybridization between T. asiatica and T. saginata is probably an ongoing event in many areas in which they are sympatrically endemic. Crown Copyright (C) 2012 Published by Elsevier Ireland Ltd. All rights reserved.

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  • Taeniasis and cysticercosis due to Taenia solium in Japan. Reviewed International journal

    Tetsuya Yanagida, Yasuhito Sako, Minoru Nakao, Kazuhiro Nakaya, Akira Ito

    Parasites & vectors   5   18 - 18   2012.1

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    Taenia solium is a zoonotic cestode that causes taeniasis and cysticercosis in humans. The parasite is traditionally found in developing countries where undercooked pork is consumed under poor sanitary conditions and/or as part of traditional food cultures. However, the recent increase in international tourism and immigration is spreading the disease into non-endemic developed countries such as the United States. Although there has been concern that the number of cysticercosis cases is increasing in Japan, the current situation is not clear. This is largely because taeniasis and cysticercosis are not notifiable conditions in Japan and because there have been no comprehensive reviews of T. solium infections in Japan conducted in the last 15 years. Herein, we provide an overview of the status of T. solium infection in Japan over the past 35 years and point out the potential risks to Japanese society.

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  • Echinococcus and Taenia spp. from captive mammals in the United Kingdom. Reviewed

    Boufana B., Stidworthy MF, Bell S., Chantrey J., Masters N., Unwin S., Wood R., Lawrence RP, Potter A., McGarry J., Redrobe S., Killick R., Foster AP, Mitchell S., Greenwood AG, Sako Y., Nakao M., Ito A., Wyatt K., Lord B., Craig PS

    Vet Parasitol   190 ( 1-2 )   95 - 103   2012

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  • Serological and molecular tools to detect neurologic parasitic zoonoses in rural Cameroon. Reviewed International journal

    Agathe Nkouawa, Yasuhito Sako, Roger Moyou-Somo, Akira Ito

    The Southeast Asian journal of tropical medicine and public health   42 ( 6 )   1365 - 74   2011.11

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    Parasitic helminthiases, such as toxocariasis, cysticercosis and paragonimiasis are a public health threat, since they can affect the brain leading to neurological disorders. Epilepsy and paragonimiasis are common in southwestern Cameroon. We reviewed the literature for studies using antigens to diagnose toxocariasis, cysticercosis, and paragonimiasis. Serology revealed that 61 (36.3%), 26 (15.5%) and 2 (1.2%) of 168 persons examined [78 males (15.2 +/- 8.2 years old), 90 females (12.9 +/- 5.9 years old), 143 persons < 20 years old] had antibody responses to toxocariasis, paragonimiasis and cysticercosis, respectively. Of the 14 people with epilepsy, 5 were seropositive for Toxocara antigens and 1 was positive for both Toxocara and Paragonimus antigens. Two children were serologically confirmed to have cysticercosis. Serologic screening for cysticercosis may be feasible to detect asymptomatic cysticercosis in children in endemic areas leading to early treatment. The causative Paragonimus species was confirmed to be P. africanus by molecular sequencing. Education, screening and confirmation test for these diseases may be needed for control in Cameroon.

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  • Post-treatment follow-up study of abdominal cystic echinococcosis in tibetan communities of northwest sichuan province, china Reviewed

    Li T., Ito A., Pengcuo R., Sako Y., Chen X., Qiu D., Xiao N., Craig PS

    PLoS Negl Trop Dis   5   e1364   2011.10

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  • A case of pulmonary and hepatic cystic Echinococcosis of CE1 stage in a healthy Japanese female that was suspected to have been acquired during her stay in the United Kingdom Reviewed

    Nakamura K., Ito A., Yara S., Haranaga S., Hibiya K., Hirayasu T., Sako Y., Fujita J.

    Am J Trop Med Hyg   85   456 - 459   2011.9

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  • Immunochromatographic test with recombinant Em18 antigen for the follow-up study of alveolar echinococcosis. Reviewed International journal

    Yasuhito Sako, Dennis Tappe, Kenta Fukuda, Yukuharu Kobayashi, Sonoyo Itoh, Matthias Frosch, Beate Grüner, Peter Kern, Akira Ito

    Clinical and vaccine immunology : CVI   18 ( 8 )   1302 - 5   2011.8

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    The performance of a rapid and simple immunochromatographic test (ICT) with recombinant Em18 (rEm18) antigen for serological follow-up of Echinococcus multilocularis infection was evaluated by comparison with that of an enzyme-linked immunosorbent assay (ELISA) with rEm18, using serum samples from patients who underwent surgery and/or received antiparasitic chemotherapy. The degree of Em18-band intensity on the ICT correlated highly with the absorbance value obtained by the ELISA. The kinetics of antibody levels obtained by the ICT paralleled those of the ELISA. These data suggest that the ICT has high potential as an easy-to-handle, fast, and reliable follow-up tool to monitor the status of alveolar echinococcosis in different stages.

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  • Neurocysticercosis case with tuberculoma-like epithelial granuloma strongly suspected by serology and confirmed by mitochondrial DNA. Reviewed

    Maeda T., Ito A., Sako Y., Yamasaki H., Oyaizu N., OdawaraT., Iwamoto A., Fujii T.

    BMJ Case Reports   2011.7

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  • Should possible recurrence of disease contraindicate liver transplantation in patients with end-stage alveolar echinococcosis? A 20-year follow-up study Reviewed

    Bresson-Hadni S., Blagosklonov O., Knapp J., Grenouillet F., Sako Y., Delabrousse E., Brientini MP, Richou C., Minello A., Antonino AT, Gillet M., Ito A., Mantion GA, Vuitton DA

    Liver Transpl   17   855 - 865   2011.7

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  • The first workshop towards the control of cestode zoonoses in Asia and Africa. International journal

    Akira Ito, Munehiro Okamoto, Tiaoying Li, Toni Wandra, Nyoman S Dharmawan, Kadek I Swastika, Paron Dekumyoy, Teera Kusolsuk, Abmed Davvajav, Anu Davaasuren, Temuulen Dorjsuren, Sissay M Mekonnen, Zerihun H Negasi, Tetsuya Yanagida, Yasuhito Sako, Minoru Nakao, Kazuhiro Nakaya, Antti J Lavikainen, Agathe Nkouawa, Tahereh Mohammadzadeh

    Parasites & vectors   4   114 - 114   2011.6

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    The first workshop towards the control of cestode zoonoses in Asia and Africa was held in Asahikawa Medical University, Japan on 15 and 16 Feb 2011. This meeting was fully supported by the Asian Science and Technology Strategic Cooperation Promotion Programs sponsored by the Special Coordination Funds for Promoting Science and Technology, the Ministry of Education Japan (MEXT) for 3 years from 2010 to Akira Ito. A total of 24 researchers from 9 countries joined together and discussed the present situation and problems towards the control of cestode zoonoses. As the meeting was simultaneously for the establishment of joint international, either bilateral or multilateral collaboration projects, the main purposes were directed to 1) how to detect taeniasis/cysticercosis infected patients, 2) how to differentiate Taenia solium from two other human Taenia species, T. saginata and T. asiatica, 3) how to evaluate T. asiatica based on the evidence of hybrid and hybrid-derived adult tapeworms from Thailand and China, 4) how to evaluate T. solium and T. hyaenae and other Taenia species from the wild animals in Ethiopia, and 5) how to detect echinococcosis patients and 6) how to differentiate Echinococcus species worldwide. Such important topics are summarized in this meeting report.

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  • Echinococcus multilocularis: Identification and functional characterization of cathepsin B-like peptidases from metacestode Reviewed

    Yasuhito Sako, Kazuhiro Nakaya, Akira Ito

    EXPERIMENTAL PARASITOLOGY   127 ( 3 )   693 - 701   2011.3

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    Cysteine peptidases have potent activities in the pathogenesis of various parasitic infections, and are considered as targets for chemotherapy and antigens for vaccine. In this study, two cathepsin B-like cysteine peptidases (EmCBP1 and EmCBP2) from Echinococcus multilocularis metacestodes were identified and characterized. Immunoblot analyses demonstrated that EmCBP1 and EmCBP2 were present in excretory/secretory products and extracts of E. multilocularis metacestodes. By immunohistochemistry. EmCBP1 and EmCBP2 were shown to localize to the germinal layer, the brood capsule and the protoscolex. Recombinant EmCBP1 and EmCBP2 expressed in Pichia pastoris, at optimum pH 5.5, exhibited substrate preferences for Z-Phe-Arg-MCA. Z-Val-Val-Arg-MCA, and Z-Leu-Arg-MCA, and low levels of hydrolysis of Z-Arg-Arg-MCA. Furthermore, recombinant enzymes degraded IgG, albumin, type I and IV collagens, and fibronectin. These results suggested that EmCBP1 and EmCBP2 may play key roles in protein digestion for parasites&apos; nutrition and in parasite-host interactions. (C) 2010 Elsevier Inc. All rights reserved.

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  • A possible nuclear DNA marker to differentiate the two geographic genotypes of Taenia solium tapeworms Reviewed

    Marcello Otake Sato, Yasuhito Sako, Minoru Nakao, Toni Wandra, Kazuhiro Nakaya, Tetsuya Yanagida, Akira Ito

    PARASITOLOGY INTERNATIONAL   60 ( 1 )   108 - 110   2011.1

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    Cysticercosis caused by infection with embryonated eggs of the pork tapeworm Taenia solium is an important cause of neurological disease worldwide. Based on the phylogenetic analysis of mitochondrial DNA, the pathogen has been divided into two geographic clades, corresponding to Afro-American and Asian genotypes. In this study the genotyping of T. solium was carried out by using the nuclear DNA sequences of the immunodiagnostic antigen genes Ag1V1 and Ag2. The two geographic genotypes were supported by the Ag2 sequences, especially showing unique substitutions in each of the genotypes. It seems likely that the Ag2 may be a novel nuclear DNA marker to distinguish the two geographic genotypes of T. solium. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

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  • Usefulness of serological and molecular tools for detection of neurologic parasitic zoonoses in rural areas of southwest Cameroon: toxocariasis, cysticercosis and paragonimiasis. Reviewed

    Nkouawa A., Sako Y., Moyou-Somo R., Ito A.

    Southeast Asian J Trop Med Public Health   42   1365 - 1374   2011

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  • Taeniasis/cysticercosis in Bali, Indonesia Reviewed

    Wandra T., Sudewi RAA, Swastika IK, Sutisna P., Dharmawan NS, Yulfi H., Darlan DM, Kapti IN, Samaan G., Sato MO, Okamoto M., Sako Y., Ito A.

    Southeast Asian J Trop Med Public Health   42   793 - 802   2011

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  • Molecular and serological survey on taeniasis and cysticercosis in Kanchanaburi Province, Thailand Reviewed

    Malinee T. Anantaphruti, Munehiro Okamoto, Tippayarat Yoonuan, Surapol Saguankiat, Teera Kusolsuk, Megumi Sato, Marcello O. Sato, Yasuhito Sako, Jitra Waikagul, Akira Ito

    PARASITOLOGY INTERNATIONAL   59 ( 3 )   326 - 330   2010.9

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    A community-based field survey on taeniasis and cysticercosis was performed in two villages in Thong Pha Phum District, Kanchanaburi Province, central Thailand, where 3 Taenia species, T. solium, T. saginata and T. asiatica, are sympatrically occurring. Four (0.6%) out of 667 stool samples were egg-positive for Taenia sp. by Kato-Katz technique. Three out of those four persons and other three persons who were Taenia egg-negative but having a recent (&lt;1 year) history of discharging worms in stool were treated with niclosamide. One Taenia egg-positive woman was not treated because of severe ascites. After treatment, three persons expelled long strobilae with scolices and two persons expelled strobilae without scolex. One Taenia egg-positive person did not expel any worms post-treatment. Among 5 persons, four expelled a single worm, whereas one expelled multiple worms, may be 6 worms but not confirmed by detection of scolices. One scolex was armed with hooklets, whereas 2 others did not. Multiplex PCR of 10 expelled proglottids (including 6 estimated worms from one patient) revealed that one sample was T. solium, one T. saginata, and 8 T. asiatica. A total of 159 residents agreed to receive a serological test for cysticercosis. By ELISA using partially purified glycoprotein antigen, 9 cases, 5 and 4 from villages A and B respectively, were found to be sero-positive. The five and an additional sample on the border line from village A were evaluated using confirmative immunoblot using recombinant chimeric antigen. Among the six samples, four including the border line sample were confirmed to be cysticercosis by immunoblotting. One of the 4 persons had neurological symptoms with nodular lesions in the brain by computed tomography. These 4 confirmed or suspected cysticercosis cases were free of T. solium worms, but two of them including confirmed NCC case had a past (&gt;1 year) history of expelling proglottids in the stool. (c) 2010 Published by Elsevier Ireland Ltd.

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  • Evaluation of a Loop-Mediated Isothermal Amplification Method Using Fecal Specimens for Differential Detection of Taenia Species from Humans Reviewed

    Agathe Nkouawa, Yasuhito Sako, Tiaoying Li, Xingwang Chen, Toni Wandra, I. Kadek Swastika, Minoru Nakao, Tetsuya Yanagida, Kazuhiro Nakaya, Dongchuan Qiu, Akira Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   48 ( 9 )   3350 - 3352   2010.9

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    We compared the performance of loop-mediated isothermal amplification (LAMP) with that of a multiplex PCR method for differential detection of human Taenia parasites in fecal specimens from taeniasis patients. The LAMP method, with no false positives, showed a higher sensitivity (88.4%) than the multiplex PCR (37.2%). Thus, it is expected that the LAMP method has a high value for molecular diagnosis of taeniasis.

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  • Serological studies of neurologic helminthic infections in rural areas of southwest cameroon: toxocariasis, cysticercosis and paragonimiasis. Reviewed International journal

    Agathe Nkouawa, Yasuhito Sako, Sonoyo Itoh, Alida Kouojip-Mabou, Christ Nadège Nganou, Yasuaki Saijo, Jenny Knapp, Hiroshi Yamasaki, Minoru Nakao, Kazuhiro Nakaya, Roger Moyou-Somo, Akira Ito

    PLoS neglected tropical diseases   4 ( 7 )   e732   2010.7

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    BACKGROUND: Both epilepsy and paragonimiasis had been known to be endemic in Southwest Cameroon. A total of 188 people (168 and 20 with and without symptoms confirmed by clinicians, respectively, 84.6% under 20 years old) were selected on a voluntary basis. Among 14 people (8.3%) with history of epilepsy, only one suffered from paragonimiasis. Therefore, we challenged to check antibody responses to highly specific diagnostic recombinant antigens for two other helminthic diseases, cysticercosis and toxocariasis, expected to be involved in neurological diseases. Soil-transmitted helminthic infections were also examined. METHODOLOGY/PRINCIPAL FINDINGS: Fecal samples were collected exclusively from the 168 people. Eggs of Ascaris lumbricoides, Trichuris trichiura and hookworms were found from 56 (33.3%), 72 (42.8%), and 19 (11.3%) persons, respectively. Serology revealed that 61 (36.3%), 25 (14.9%) and 2 (1.2%) of 168 persons showed specific antibody responses to toxocariasis, paragonimiasis and cysticercosis, respectively. By contrast, 20 people without any symptoms as well as additional 20 people from Japan showed no antibody responses. Among the 14 persons with epilepsy, 5 persons were seropositive to the antigen specific to Toxocara, and one of them was simultaneously positive to the antigens of Paragonimus. The fact that 2 children with no history of epilepsy were serologically confirmed to have cysticercosis strongly suggests that serological survey for cysticercosis in children is expected to be useful for early detection of asymptomatic cysticercosis in endemic areas. CONCLUSIONS/SIGNIFICANCE: Among persons surveyed, toxocariasis was more common than paragonimiasis, but cysticercosis was very rare. However, the fact that 2 children were serologically confirmed to have cysticercosis was very important, since it strongly suggests that serology for cysticercosis is useful and feasible for detection of asymptomatic cysticercotic children in endemic areas for the early treatment.

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  • Immunoglobulin G subclass responses to recombinant Em18 in the follow-up of patients with alveolar echinococcosis in different clinical stages Reviewed

    Tappe D., Sako Y., Itoh S., Frosch M., Gruner B., Kern P., Ito A.

    Clin Vaccine Immunol   17   944 - 948   2010.6

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  • Neurocysticercosis: assessing where the infection was acquired from Reviewed

    Yanagida T., Yuzawa I., Joshi DD, Sako Y., Nakao M., Nakaya K., Kawano N., Oka H., Fujii K., Ito A.

    J Travel Med   17   206 - 208   2010.5

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  • State-of-the-art Echinococcus and Taenia: Phylogenetic taxonomy of human-pathogenic tapeworms and its application to molecular diagnosis Reviewed

    M. Nakao, T. Yanagida, M. Okamoto, J. Knapp, A. Nkouawa, Y. Sako, A. Ito

    Infection, Genetics and Evolution   10 ( 4 )   444 - 452   2010.5

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  • Specific IgG Responses to Recombinant Antigen B and Em18 in Cystic and Alveolar Echinococcosis in China Reviewed

    Tiaoying Li, Akira Ito, Xingwang Chen, Yasuhito Sako, Jiamin Qiu, Ning Xiao, Dongchuan Qiu, Minoru Nakao, Tetsuya Yanagida, Philip S. Craig

    CLINICAL AND VACCINE IMMUNOLOGY   17 ( 3 )   470 - 475   2010.3

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    An understanding of the correlation of the specific antibody responses and the disease phase is essential in evaluating diagnostic values of immunological tests in human echinococcosis. In this study, 422 echinococcosis patients diagnosed by ultrasonography, including 246 with cystic echinococcosis (CE), 173 with alveolar echinococcosis (AE), and 3 with dual infection, were tested for specific IgG in sera against recombinant AgB (rAgB) and recombinant Em18 (rEm18) in an enzyme-linked immunosorbent assay. As a result, rAgB-specific antibody was detected in 77.6% of CE and 86.1% of AE patients, while rEm18-specific antibody was present in 28.9% of CE and 87.3% of AE patients. Additionally, all three patients with dual infection exhibited specific antibodies responding to rAgB and rEm18. Further analysis revealed that rAgB-specific antibody was elevated in a significantly greater proportion ( 87.3%) of CE patients with cysts at active or transitional stages (CE1, CE2, or CE3), compared to 54.8% of other patients with cysts at an early or an inactive stage ( CL or CE4 or CE5). Furthermore, rAgB-specific antibody was detected in 95.6% of CE2 cases, which was statistically greater than that (73.7%) in CE1 patients. Although rEm18-specific antibody was elevated in 28.9% of CE patients, the positive reaction was much weaker in CE than in AE cases. Serum levels and concentrations of rEm18-specific antibody were further indicated to be strongly disease phase correlated in AE patients, with positive rates of 97.4% in cases with alveolar lesions containing central necrosis and 66.7% in patients with early alveolar lesions that measured &lt;= 5 cm.

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  • Short Report: Histopathological, Serological, and Molecular Confirmation of Indigenous Alveolar Echinococcosis Cases in Mongolia Reviewed

    Akira Ito, Gurbadam Agvaandaram, Oyun-Erdene Bat-Ochir, Batsaikhan Chuluunbaatar, Nyamkhuu Gonchigsenghe, Tetsuya Yanagida, Yasuhito Sako, Narankhajid Myadagsuren, Temuulen Dorjsuren, Kazuhiro Nakaya, Minoru Nakao, Yuji Ishikawa, Abmed Davaajav, Nyamkhuu Dulmaa

    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE   82 ( 2 )   266 - 269   2010.2

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    Alveolar echinococcosis cases diagnosed histopathologically in 2002, 2006, 2007 and 2009 in Ulaanbaatar, Mongolia were reconfirmed by evaluating the cytochrome c oxidase subunit I gene of mitochondrial DNA. The most recent three Cases using paraffin-e in bedded and ethanol-fixed specimens revealed that one was of the "Asian" haplotype, whereas two others were of the "Inner Mongolian" type. All patients were born in the western provinces of Mongolia, they never resided outside of Mongolia, and they were given a preliminary diagnosis of malignant hepatic tumor or abscess. The most recent two cases were also confirmed serologically to be active alveolar echinococcosis.

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  • Echinococcus vogeli infection in a hunter, French Guiana. Reviewed

    Knapp J., Chirica M., Simonnet C., Grenouillet F., Bart JM, Sako Y., Itoh S., Nakao M., Ito A., Millon L.

    Emerg Infect Dis   15   2029 - 2031   2009.12

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  • Geographic pattern of genetic variation in the fox tapeworm Echinococcus multilocularis Reviewed

    M. Nakao, N. Xiao, M. Okamoto, T. Yanagida, Y. Sako, A. Ito

    Parasitology International   58 ( 4 )   384 - 389   2009.12

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  • Serological monitoring of progression of alveolar echinococcosis with multiorgan involvement by use of recombinant Em18. Reviewed

    Ishikawa Y., Sako Y., Itoh S., Ohtake T., Kohgo Y., Matsuno T., Ohsaki Y., Miyokawa N., Nakao M., Nakaya K., Ito A.

    J Clin Microbiol   47   3191 - 3196   2009.10

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  • Close relationship between clinical regression and specific serology in the follow-up of patients with alveolar echinococcosis in different clinical stages. Reviewed

    Tappe D., Frosch M., Sako Y., Itoh S., Gruner B., Reuter S., Nakao M., Ito A., Kern P.

    Am J Trop Med Hyg   80   792 - 797   2009.5

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  • Paragonimiasis in Cameroon: molecular identification, serodiagnosis and clinical manifestations Reviewed

    A. Nkouawa, M. Okamoto, A.K. Mabou, E. Edinga, H. Yamasaki, Y. Sako, M. Nakao, K. Nakaya, D. Blair, T. Agatsuma, P. Enyong, T. Shibahara, R. Moyou-Somo, A. Ito

    Transactions of the Royal Society of Tropical Medicine and Hygiene   103 ( 3 )   255 - 261   2009.3

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  • Widespread co-endemicity of human cystic and alveolar echinococcosis on the eastern Tibetan Plateau, northwest Sichuan/southeast Qinghai, China. Reviewed

    Li T., Chen X., Zhen R., Qiu J., Qiu D., Xiao N., Ito A., Wang H., Giraudoux P., Sako Y., Nakao M., Craig PS

    Acta Trop   113 ( (3) )   248 - 256   2009.3

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  • Development of an Immunochromatographic Test To Detect Antibodies against Recombinant Em18 for Diagnosis of Alveolar Echinococcosis Reviewed

    Yasuhito Sako, Kenta Fukuda, Yukuharu Kobayashi, Akira Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   47 ( 1 )   252 - 254   2009.1

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    An immunochromatographic test (ICT) for the rapid detection of antibodies to Echinococcus multilocularis was developed. The ICT showed a sensitivity of 94% and a specificity of 95.4%. High degrees of agreement were observed between the ICT and an enzyme-linked immunosorbent assay (kappa = 0.93) and between the ICT and immunoblot analysis (kappa = 0.97). It is expected that the ICT developed in this study will be useful for the serodiagnosis of alveolar echinococcosis.

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  • Loop-Mediated Isothermal Amplification Method for Differentiation and Rapid Detection of Taenia Species Reviewed

    Agathe Nkouawa, Yasuhito Sako, Minoru Nakao, Kazuhiro Nakaya, Akira Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   47 ( 1 )   168 - 174   2009.1

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    Rapid detection and differentiation of Taenia species are required for the control and prevention of taeniasis and cysticercosis in areas where these diseases are endemic. Because of the lower sensitivity and specificity of the conventional diagnosis based on microscopical examination, molecular tools are more reliable for differential diagnosis of these diseases. In this study, we developed and evaluated a loop-mediated isothermal amplification (LAMP) assay for differential diagnosis of infections with Taenia species with cathepsin L-like cysteine peptidase (clp) and cytochrome c oxidase subunit 1 (cox1) genes. LAMP with primer sets to the cox1 gene could differentiate between three species, and LAMP with primer sets to the clp gene could differentiate Taenia solium from Taenia saginata/Taenia asiatica. Restriction enzyme digestion of the LAMP products from primer set Tsag-clp allowed the differentiation of Taenia saginata from Taenia asiatica. We demonstrated the high specificity of LAMP by testing known parasite DNA samples extracted from proglottids (n = 100) and cysticerci (n = 68). LAMP could detect one copy of the target gene or five eggs of T. asiatica and T. saginata per gram of feces, showing sensitivity similar to that of PCR methods. Furthermore, LAMP could detect parasite DNA in all taeniid egg-positive fecal samples (n = 6). Due to the rapid, simple, specific, and sensitive detection of Taenia species, the LAMP assays are valuable tools which might be easily applicable for the control and prevention of taeniasis and cysticercosis in countries where these diseases are endemic.

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  • Genetic characterization and phylogenetic position of Echinococcus felidis Ortlepp, 1937 (Cestoda : Taeniidae) from the African lion Reviewed

    Marion Huettner, Minoru Nakao, Torsten Wassermann, Ludwig Siefert, Joop D. F. Boomker, Anke Dinkel, Yasuhito Sako, Ute Mackenstedt, Thomas Romig, Akira Ito

    INTERNATIONAL JOURNAL FOR PARASITOLOGY   38 ( 7 )   861 - 868   2008.6

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    Echinococcus felidis had been described in 1937 from African lions, but was later included in Echinococcus granulosus as a subspecies or a strain. In the absence of any genetic characterization, most previous records of this taxon from a variety of large African mammals remained unconfirmed due to the lack of diagnostic criteria and the possible confusion with the sympatric E granulosus sensu stricto, Echinococcus ortleppi and Echinococcus canadensis. In this study, we obtained taeniid eggs from lion feces in Uganda and amplified DNA from individual eggs. Mitochondrial and nuclear DNA sequences showed similarities with those of other Echinococcus spp., but high values of percentage divergence of mitochondrial genes indicated the presence of a distinct species. In a second step, we compared this material with the preserved specimens of adult E. granulosus felidis, which had been identified morphologically approximately 40 years ago in South Africa. All DNA fragments (&lt;200 bp) that could be amplified from the adults showed 100% similarity with the Ugandan material. In the phylogenetic tree of Echinococcus which was constructed from the mitochondrial genes, E felidis is positioned as a sister taxon of E granulosus sensu stricto. The data obtained will facilitate the development of diagnostic tools necessary to study the epidemiology of this enigmatic parasite. (C) 2007 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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  • Molecular characterization of a novel gene encoding an 8-kDa-subunit of antigen B from Echinococcus granulosus genotypes 1 and 6 Reviewed

    Mamuti Wulamu, Yasuhito Sako, Jean-Mathieu Bart, Minoru Nakao, Xiurnin Ma, Hao Wen, Akira Ito

    PARASITOLOGY INTERNATIONAL   56 ( 4 )   313 - 316   2007.12

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    Antigen B in hydatid cyst fluid of Echinococcus granulosus is a polymeric lipoprotein of 160 kDa, and is an aggregate of several different but homologous small proteins with approximately 8 kDa which are encoded by a multigene family. Four genes encoding 8-kDa-subunit monomers of the antigen B have been identified from E. granulosus. Recently, we have isolated another novel gene from Echinococcus multilocularis encoding a fifth 8-kDa-subunit of AgB (named EmAgB8/5), predominantly transcribed in the adult worm, but not in vesicles of metacestodes. In this study, we cloned and characterized two ErnAgB8/5 homologue genes from E. granulosus genotypes 1 and 6 by PCR, and named as EgG1AgB8/5 and EgG6AgB8/5, respectively. The phylogenetic relationship of these genes with other genes encoding the antigen B 8-kDa-subunit monomers was also discussed. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

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  • Sympatric occurrence of Taenia solium, T-saginata, and T-asiatica, Thailand Reviewed

    Malinee T. Anantaphruti, Hiroshi Yamasaki, Minoru Nakao, Jitra Waikagul, Dorn Watthanakulpanich, Supaporn Nuamtanong, Wanna Maipanich, Somchit Pubampen, Surapol Sanguankiat, Chatree Muennoo, Kazuhiro Nakaya, Marcello O. Sato, Yasuhito Sako, Munehiro Okamoto, Akira Ito

    EMERGING INFECTIOUS DISEASES   13 ( 9 )   1413 - 1416   2007.9

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    We confirmed sympatric occurrence of Taenia solium, T. saginata, and T. asiatica in western Thailand. DNA analysis of morphologically identified T. saginata, in a dual infection with T. solium, indicated it was T. asiatica. To our knowledge, this report is the first of T. asiatica and a dual Taenia infection from Thailand.

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  • Comparison of several commercial serologic kits and Em18 serology for detection of human alveolar echinococcosis Reviewed

    Jean-Mathieu Bart, Martine Piarroux, Yasuhito Sako, Frederic Grenouillet, Solange Bresson-Hadni, Renaud Piarroux, Akira Ito

    DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE   59 ( 1 )   93 - 95   2007.9

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    The aim of this study was to design the best serologic strategy for diagnosing human alveolar echinococcosis (AE) cases in medical laboratory routine procedures. By combining 2 screening techniques, indirect hemagglutination with Em(2plus)-ELISA and/or recEm18-ELISA, 46 of 47 AE cases were detected. The necessary confirmation of results is then obtained by using immunoblot (LDBIO-IB (R) and/or recEm 18-IB). (c) 2007 Elsevier Inc. All rights reserved.

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  • Taeniasis in Mongolia, 2002-2006. Reviewed

    Myadagsuren N., Davaajav A., Wandra T., Sandar T., Ichinkhorloo P., Yamasaki H., Sako Y., Nakao M., Sato MO, Nakaya K., Ito A.

    Am J Trop Med Hyg   77   342 - 346   2007.8

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  • Cloning and characterization of cathepsin L-like peptidases of Echinococcus multilocularis metacestodes Reviewed

    Yasuhito Sako, Hiroshi Yamasaki, Kazuhiro Nakaya, Minoru Nakao, Akira Ito

    MOLECULAR AND BIOCHEMICAL PARASITOLOGY   154 ( 2 )   181 - 189   2007.8

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    Cysteine peptidases have potent activities in the pathogenesis of various parasitic infections. Two cDNA clones encoding cysteine peptidases were isolated from Echinococcus multilocularis metacestode (EmCLP1 and EmCLP2). EmCLP1 and EmCLP2 shared high similarity to the cathepsin L-like peptidases. Immunoblot analyses demonstrated that native EmCLP1 and EmCLP2 were present in excretory/secretory products and extracts of E. multilocularis metacestodes. By immunohistochemistry, native EmCLP1 and EmCLP2 were shown to localize to the germinal layer, the brood capsule and the protoscolex. Recombinant EmCLP1 and EmCLP2 expressed in Saccharomyces cerevisiae exhibited substrate specificity against synthetic peptidyl substrates, Z-Leu-Arg-MCA and Z-Phe-Arg-MCA. Furthermore, recombinant enzymes degraded IgG, albumin, type I and IV collagens, and fibronectin, which suggested those key roles in parasite-host interactions. This is the first report of cysteine peptidases from E. multilocularis, and would contribute to control E. multilocularis infections by chemotherapeutic drugs and/or immunoprophylaxis. (c) 2007 Elsevier B.V. All rights reserved.

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  • Evaluation of purified Taenia solium glycoproteins and recombinant antigens in the serologic detection of human and swine cysticercosis Reviewed

    Marcello Otake Sato, Yasuhito Sako, Minoru Nakao, Hiroshi Yamasaki, Kazuhiro Nakaya, Akira Ito

    JOURNAL OF INFECTIOUS DISEASES   194 ( 12 )   1783 - 1790   2006.12

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    Cysticercosis caused by infection with embryonated eggs of Taenia solium is an important cause of neurological disease worldwide. On the basis of mitochondrial DNA analysis, T. solium is divided into 2 (African/American and Asian) genotypes. Glycoproteins (GPs) in cyst fluid purified from the 2 genotypes of T. solium were characterized and compared with the recombinant chimeric T. solium-Ag1V1/Ag2 protein (Rec-Ag1V1/Ag2) as serodiagnostic antigens. Immunoblot analysis revealed that banding patterns of GPs differed between the 2 genotypes because of posttranslation modification, especially glycosylation. The comparison of native GPs with Rec-Ag1V1/Ag2 by enzyme-linked immunosorbent assay demonstrated that there was no statistical difference in sensitivity. In addition, the conservation of the genes encoding Ag1V1 and Ag2 in T. solium worldwide was verified. These results indicate that Rec-Ag1V1/Ag2 has great potential for usefulness in serodiagnosis as an alternative to native antigens.

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  • Short report: Evidence and potential for transmission of human and swine Taenia solium cysticercosis in the Piracuruca region, Piaui, Brazil. Reviewed

    Sato MO, Cavalcante TV, Sako Y., Nakao M., Yamasaki H., Yatsuda AP, Nakaya K., Ito A.

    Am J Trop Med Hyg   75   933 - 935   2006.11

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  • Echinococcus multilocularis: developmental stage-specific expression of Antigen B 8-kDa-subunits. Reviewed

    Mamuti W., Sako Y., Xiao N., Nakaya K., Nakao M., Yamasaki H., Lightowlers MW, Craig PS, Ito A.

    Exp Parasitol   113   75 - 82   2006.6

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  • A case of intramuscular cysticercosis diagnosed definitively by mitochondrial DNA analysis of extremely calcified cysts Reviewed

    H Yamasaki, T Nagase, Y Kiyoshige, M Suzuki, K Nakaya, Y Itoh, Y Sako, M Nakao, A Ito

    PARASITOLOGY INTERNATIONAL   55 ( 2 )   127 - 130   2006.6

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    A case of obsolete intramuscular cysticercosis diagnosed definitively by mitochondrial DNA analysis of extremely calcified cysts was reported. X-ray and computed tomography findings highly suggested cysticercosis due to Taenia solium; however, no direct evidence of cysticercosis was obtained through serological or histopathological examinations. Mitochondrial DNA analysis of a histopathological specimen confirmed the causative agent to be the Asian genotype of T solium. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

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  • Towards the international collaboration for detection, surveillance and control of taeniasis/ cysticercosis and echinococcosis in Asia and the Pacific. Reviewed

    Ito A., Wandra T., Sato MO, Mamuti W., Xiao N., Sako Y., Nakao M., Yamasaki H., Nakaya K., Okamoto M., Craig PS

    Southeast Asian J Trop Med Public Health   37 ( Suppl 3 )   82 - 90   2006.4

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  • Mitochondrial DNA diagnosis for taeniasis and cysticercosis. Reviewed

    Yamasaki H., Nakao M., Sako Y., Nakaya K., Sato MO, Ito A.

    Parasitol Int   55 ( Suppl )   S81 - 85   2006.4

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  • Recent advances in characterization of Echinococcus antigen B. Reviewed

    Mamuti W., Sako Y., Nakao M., Xiao N., Nakaya K., Ishikawa Y., Yamasaki H., Lightowlers MW, Ito A.

    Parasitol Int   55   S57 - 62   2006.4

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  • Usefulness of severe combined immunodeficiency (scid) and inbred mice for studies of cysticercosis and echinococcosis. Reviewed

    Nakaya K., Mamuti W., Xiao N., Sato MO, Wandra T., Nakao M., Sako Y., Yamasaki H., Ishikawa Y., Craig PS, Schantz PM, Ito A.

    Parasitol Int   55 ( Suppl )   S91 - 97   2006.4

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  • Neurocysticercosis: clinical manifestation, neuroimaging, serology and molecular confirmation of histopathologic specimens. Reviewed

    Ito A., Takayanagui OM, Sako Y., Sato MO, Odashima NS, Yamasaki H., Nakaya K., Nakao M.

    Southeast Asian J Trop Med Public Health   37 ( Suppl 3 )   74 - 81   2006.4

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  • Recombinant antigens for serodiagnosis of cysticercosis and echinococcosis Reviewed

    Y Sako, M Nakao, K Nakaya, H Yamasaki, A Ito

    PARASITOLOGY INTERNATIONAL   55   S69 - S73   2006

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    Diagnosis of cysticercosis/echinococcosis is primarily based on imaging techniques. These imaging techniques are sometimes limited by the small size of visualized lesions and atypical images, which are difficult to be distinguished from abscesses or neoplasms. Therefore, efforts have been directed toward identification and characterization of specific antigens of parasites for development of serodiagnostic method that can detect specific antibody. For cysticercosis, glycoproteins of 10-26 kDa in cyst fluid of Taenia solium have been widely accepted for serodiagnosis purpose. The glycoproteins consist of a very closely related family of 8-kDa proteins. We identified four genes (designated Ag1, Ag1V1, Ag2 and Ag2V1) encoding the 7- and 10-kDa polypeptides. Based on the antigenicities of these clones, Ag1V1 and Ag2 were chosen as ELISA antigens and the Ag1V1/Ag2 chimeric protein was expressed. The Ag1V1/Ag2 chimeric protein showed the similar sensitivity and specificity as the native glycoproteins. For alveolar echinococcosis, the 65-kDa protein of Echinococcus multilocularis protoscolices and Em18 has been considered as serodiagnostic antigens. The sensitivity and specificity of Em18 are very compatible to those of the recombinant 65-kDa protein. Recently, we demonstrated that Em 18 was the proteolytic product of the 65-kDa protein following the action by cysteine proteinases. From the information of N-terminal amino acid sequences, molecular size and isoelectric point of Em18, recombinant Em18 (K-349 to K-508 of the 65-kDa protein, RecEm18) was expressed and evaluated for serodiagnostic value. RecEm18 has the potential for use in the differential serodiagnosis of alveolar echinococcosis. (C) 2005 Elsevier Ireland Ltd. All rights reserved.

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  • Taeniasis and cysticercosis in Asia and the Pacific: present state of knowledge and perspectives. Reviewed

    Ito A., Nakao M., Wandra T., Suroso T., Okamoto M., Yamasaki H., Sako Y., Nakaya K.

    Southeast Asian J Trop Med Public Health   36 ( Suppl 4 )   123 - 30   2005.4

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  • Molecular identification of Taenia solium cysticercus genotype in the histopathological specimens. Reviewed

    Yamasaki H., Nakao M., Sako Y., Nakaya K., Ito A.

    Southeast Asian J Trop Med Public Health   36 ( Suppl 4 )   131 - 134   2005.4

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  • Short report: Echinococcus multilocularis confirmed on Kunashiri Island, 15 kilometers from the eastern part of Hokkaido, Japan. Reviewed

    Satoh M., Nakaya K., Nakao M., Xiao N., Yamasaki H., Sako Y., Naitoh Y., Kondo S., Kobayashi M., Ohtaishi N., Ito A.

    Am J Trop Med Hyg   72   284 - 288   2005.3

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  • Solitary neurocysticercosis case caused by Asian genotype of Taenia solium confirmed by mitochondrial DNA analysis. Reviewed

    Yamasaki H., Matsunaga S., Yamamura K., Chang CC, Kawamura S., Sako Y., Nakao M., Nakaya K., Ito A.

    J Clin Microbiol   42   3891 - 3893   2004.8

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    DOI: 10.1128/JCM.42.8.3891-3893.2004

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  • Cysticercosis/taeniasis in Asia and the Pacific. Reviewed

    Ito A., Wandra T., Yamasaki H., Nakao M., Sako Y., Nakaya K., Margono SS, Suroso T., Gauci C., Lightowlers MW

    Vector Borne Zoonotic Dis   4   95 - 107   2004.4

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  • Cysticercosis: IgG-ELISA evaluations of peak1 antigen and <30 kDa antigen of delipidized extract of Taenia solium metacestodes. Reviewed

    Dekumyoy P., Waikagul J., Vanijanonta S., Thairungroj M., Nakao M., Sako Y., Watanabe S., Ito A.

    Southeast Asian J Trop Med Public Health   35   1 - 9   2004.4

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  • Molecular cloning, expression, and serological evaluation of an, 8-kilodalton subunit of antigen B from Echinococcus multilocularis Reviewed

    W Mamuti, H Yamasaki, Y Sako, M Nakao, N Xiao, K Nakaya, N Sato, DA Vuitton, R Piarroux, MW Lightowlers, PS Craig, A Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   42 ( 3 )   1082 - 1088   2004.3

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    Full-length cDNA and genomic DNA encoding an 8-kDa subunit of antigen B from Echinococcus multilocularis (designated EmAgB8/1) were isolated from an E. multilocularis metacestode cDNA library and a protoscolex genomic DNA library, respectively. The open reading frame of the cDNA clone encodes a polypeptide comprising 85 amino acids with a 20-amino-acid NH(2)-terminal signal sequence, which was confirmed following N-terminal sequencing of the native antigen. Reverse transcription-PCR analysis revealed that the clone encoding EmAgB8/1 is predominantly transcribed in larval E. multilocularis. The gene consists of two exons (encoding the signal sequence and mature protein) separated by a 91-bp intron. The mature form was expressed in Escherichia coli, and its antigenic reactivity was compared with that of a counterpart, an 8-kDa subunit of antigen B from Echinococcus granulosus (EgAgB8/1) by Western blotting and enzyme-linked immunosorbent assay (ELISA) with serum samples from patients confirmed to have cystic echinococcosis (CE) and alveolar echinococcosis (AE). Recombinant EmAgB8/1 showed positive reactions in Western blots with 81.3% (65 of 80) of serum samples from CE patients and 40.6% (26 of 64) of serum samples from AE patients, while recombinant EgAgB8/1 showed positive reactions with 86% (43 of 50) and 42% (19 of 45) of the serum samples from these CE and AE patients, respectively. By the ELISA, both EmAgB8/1 and EgAgB8/1 exhibited similar positive reactions with 88% (44 of 50) of serum samples from CE patients and 37.8% (17 of 45) serum samples from AE patients. Statistical analysis revealed that the sensitivity of EmAgB8/1 was comparable to that of EgAgB8/1 for the serodiagnosis of echinococcal diseases. There was no cross-reaction with sera from patients with cysticercosis, which often cross-react when native antigens are used for serodiagnosis.

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  • DNA differential diagnosis of taeniasis and cysticercosis by multiplex PCR Reviewed

    H Yamasaki, JC Allan, MO Sato, M Nakao, Y Sako, K Nakaya, DC Qiu, W Mamuti, PS Craig, A Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   42 ( 2 )   548 - 553   2004.2

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    Multiplex PCR was established for differential diagnosis of taeniasis and cysticercosis, including their causative agents. For identification of the parasites, multiplex PCR with cytochrome c oxidase subunit 1 gene yielded evident differential products unique for Taenia saginata and Taenia asiatica and for American/African and Asian genotypes of Taenia solium with molecular sizes of 827, 269, 720, and 984 bp, respectively. In the PCR-based detection of tapeworm carriers using fecal samples, the diagnostic markers were detected from 7 of 14 and 4 of 9 T. solium carriers from Guatemala and Indonesia, respectively. Test sensitivity may have been reduced by the length of time (up to 12 years) that samples were stored and/or small sample volumes (ca. 30 to 50 mg). However, the diagnostic markers were detected by nested PCR in five worm carriers from Guatemalan cases that were found to be negative by multiplex PCR. It was noteworthy that a 720 bp-diagnostic marker was detected from a T. solium carrier who was egg-free, implying that it is possible to detect worm carriers and treat before mature gravid proglottids are discharged. In contrast to T. solium carriers, 827-bp markers were detected by multiplex PCR in all T. saginata carriers. The application of the multiplex PCR would be useful not only for surveillance of taeniasis and cysticercosis control but also for the molecular epidemiological survey of these cestode infections.

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  • Isolation of polymorphic microsatellite loci from the tapeworm Echinococcus multilocularis Reviewed

    Minoru Nakao, Yasuhito Sako, Akira Ito

    INFECTION GENETICS AND EVOLUTION   3 ( 3 )   159 - 163   2003.9

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    Two microsatellites were isolated from a genomic library of Echinococcus multilocularis. The microsatellites, designated EMms1 and EMms2, consist of tandem repeats of CAC-trinucleotide unit. Southern blot hybridization suggests that each of them is a single locus. Using fox-derived wild tapeworms (N = 104), PCR-amplification of microsatellites was performed to assess the usefulness of these loci. We found four alleles of EMms1 and two alleles of EMms2. The heterozygosities observed were 10.6% in EMms1 and 7.7% in EMms2. The result suggests that both selfing and outcrossing occur in the adult stage of E. multilocularis. (C) 2003 Elsevier Science B. V. All rights reserved.

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  • Multiple genotypes of Taenia solium - ramifications for diagnosis, treatment and control Reviewed

    A Ito, H Yamasaki, M Nakao, Y Sako, M Okamoto, MO Sato, K Nakaya, SS Margono, T Ikejima, AA Kassuku, SMS Afonso, WB Ortiz, A Plancarte, A Zoli, S Geerts, PS Craig

    ACTA TROPICA   87 ( 1 )   95 - 101   2003.6

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    Mitochondrial DNA sequences of Taenia solium have fully been analyzed. Analysis of the full length of cytochrome c oxidase subunit 1 (1620 bp) and cytochrome b (1068 bp) genes of T solium, isolated from Asia (China, Thailand, Indonesia and India), from Latin America (Mexico, Ecuador, Bolivia, Peru and Brazil) and from Africa (Tanzania, Mozambique and Cameroon), has revealed that the two phylogenies obtained were similar to each other regardless of the genes examined. The isolates from Asia formed a single cluster, whereas those from Latin America combined with those from Africa to form an additional cluster. It was estimated that these two genotypes emerged approximately 4-8 x 10(5) years ago. These results together with recent study of the ancient of human taeniid cestodes emerged several MYA in Africa, historical data on swine domestication, distribution of pigs and colonization patterns suggest that T solium was introduced recently into Latin America and Africa from different regions of Europe during the colonial age, which started 500 years ago, and that T solium of another origin independently spread in Asian countries, perhaps from China. Why did not T solium of European origin invade or spread into Asia during the colonial age? Analysis of T. solium distribution must include other Taenia species, especially T saginata and T asiatica, which can not be differentiated from each other morphologically. BESS T-base analysis for differentiation of all human Taenia species including the two genotypes of T. solium, and T saginata and T asiatica has also been characterized. BESS T-base analysis differentiates African isolates from Latin American isolates as well but more samples should be analyzed for obtaining conclusive evidence for the latter. Serological analysis of cyst fluid of T solium cysticerci obtained in China and Indonesia and from Mozambique and Ecuador indicates geographical differences in their banding patterns. These differences are discussed in the light of possible differences in pathology of T solium worldwide. As it has been speculated that the ancient T. solium emerged several million years ago in Africa, it is necessary to analyze more isolates from Africa. Such working hypothesis may be evaluated combined with symptomatology and serology when we get additional DNA data from such areas, since there are some varieties of manifestation of neurocysticercosis with or without subcutaneous cysticercosis and of antigens of cyst fluid of T solium from Asia and from Africa and/or America. Transfer of techniques of molecular identification and sero- and immuno-diagnoses between researchers and technicians from endemic countries using their own materials should be promoted with the aim of better international cooperation for the control of cysticercosis. (C) 2003 Elsevier Science B.V. All rights reserved.

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  • The mitochondrial genome of the tapeworm Taenia solium: A finding of the abbreviated stop codon U Reviewed

    M Nakao, Y Sako, A Ito

    JOURNAL OF PARASITOLOGY   89 ( 3 )   633 - 635   2003.6

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    The complete nucleotide sequence of the tapeworm Taenia solium mitochondrial DNA (mtDNA) has been determined. The sequence is 13.709 base pairs in length and contains 36 genes (12 for proteins involved in oxidative phosphorylation, 2 for ribosomal RNAs, and 22 for transfer RNAs). The gene content and organization of the T. solium mtDNA are identical to those of other taeniid mtDNAs. All genes are transcribed in the same direction, and all protein-coding genes appear to initiate with the AUG or GUG codon. In a gene for NADH dehydrogenase subunit 1, the abbreviated stop codon U was confirmed for the first time in flatworm mtDNAs.

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  • Development of Em18-immunoblot and Em18-ELISA for specific diagnosis of alveolar echinococcosis Reviewed

    A Ito, Y Sako, H Yamasaki, W Mamuti, K Nakaya, M Nakao, Y Ishikawa

    ACTA TROPICA   85 ( 2 )   173 - 182   2003.2

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    Extensive experience has documented that Em2(plus)-ELISA, Em10-ELISA and Em18-immunoblot and Em18-ELISA are reliable serologic methods for detection of alveolar echinococcosis (AE) caused by the metacestodes of Echinococcus multilocularis. Among these, tests based on detection of antibodies to the specific Em 18 antigen, either immunoblot or ELISA, appears to be the most specific for AE. Between 90 and 97%, of AE cases with characteristic hepatic lesions detectable by image analysis have been positive in Em18-serology. In contrast Antigen B (8 kDa)-immunoblot is the most sensitive for all forms of echinococcosis, although it can not differentiate AE from cystic echinococcosis (CE). Primary serologic screening for echinococcosis, especially for CE using hydatid cyst fluid of Echinococcus granulosus appears to be highly sensitive in endemic areas. Glycoproteins (GPs) purified from cyst fluid of Taenia solium are highly specific for diagnosis of T solium neuorcysticercosis (NCC). Using currently available antigens it is not difficult to differentiate these three larval cestodiases serologically. We recommend that (1) primary screening of CE in endemic areas should be carried out using hydatid cyst fluid of E granulosus prepared from cysts in either sheep, human or mouse for immunoblot and from sheep or mouse for ELISA, (2) both primary screening and confirmation of AE in endemic areas should be carried out using Em18-ELISA, Em18-immunoblot or Em2(plus)-ELISA. Serodiagnosis in areas where both AE and CE are endemic, such as in China, should be carried out as a combination of (1) and (2), and (3) serology of NCC should be carried out using GP-ELISA or GP-immunoblot. All samples showing antibody to Em18 are exclusively from echinococcosis cases. There have been no false positive test reactions with sera from other diseases. Strongest Em18 responders are all from patients with AE but some weaker responses may be found in sera of persons with advanced complex lesions of CE. These highly reliable serodiagnostic methods using native, recombinant and synthetic antigens are briefly summarized and experiences with these methods in Japan is reviewed. We believe that use of these specific antigens in screening and confirmation programs for AE in Japan will improve specificity and reduce the confusion, anxiety and expense in persons whose sera give false positive reactions with crude echinococcal antigens. (C) 2002 Elsevier Science B.V. All rights reserved.

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  • Evaluation of an enzyme-linked immunosorbent assay (ELISA) with affinity-purified Em18 and an ELISA with recombinant Em18 for differential diagnosis of alveolar echinococcosis: Results of a blind test Reviewed

    A Ito, N Xiao, M Liance, MO Sato, Y Sako, W Mamuti, Y Ishikawa, M Nakao, H Yamasaki, K Nakaya, K Bardonnet, S Bresson-Hadni, DA Vuitton

    JOURNAL OF CLINICAL MICROBIOLOGY   40 ( 11 )   4161 - 4165   2002.11

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    Alveolar echinococcosis (AE) is the most potentially lethal parasitic zoonosis of the nontropical areas in the northern hemisphere, where cystic echinococcosis (CE) is also endemic. Both AE and CE are highly endemic in China, and both serologic detection of echinococcosis, either AE or CE, and differentiation of AE from CE are crucial problems. Evaluation of Western blot analysis (WB) and enzyme-linked immunosorbent assay (ELISA) for the Em18 antigen, using affinity-purified and recombinant Em18, was carried out "blindly" using 60 human sera from patients diagnosed in France. The results were compared with those obtained using a commercially available Echinococcus WB immunoglobulin G (IgG) kit developed in France. The Em18 WB and Echinococcus WB IgG showed very similar results for detection of AE. Both affinity-purified Em18 or a recombinant Em 18 WB and Echinococcus WB IgG seem useful for identification of AE, and the latter seems appropriate for both AE and CE, whereas affinity-purified Em18 ELISA and the newly developed recombinant Em18 ELISA appear to be suitable for detection of AE, especially for epidemiological surveys.

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  • DNA differential diagnosis of human taeniid cestodes by base excision sequence scanning thymine-base reader analysis with mitochondrial genes Reviewed

    H. Yamasaki, M. Nakao, Y. Sako, K. Nakaya, M.O. Sato, W. Mamuti, M. Okamoto, A. Ito

    Journal of Clinical Microbiology   40 ( 10 )   3818 - 3821   2002.10

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  • The complete mitochondrial DNA sequence of the cestode Echinococcus multilocularis (Cyclophyllidea : Taeniidae) Reviewed

    M Nakao, N Yokoyama, Y Sako, M Fukunaga, A Ito

    MITOCHONDRION   1 ( 6 )   497 - 509   2002.10

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    The 13,738 bp mitochondrial DNA from the cestode Echinococcus multilocularis has been sequenced. It contains two major noncoding regions and 36 genes (12 for proteins involved in oxidative phosphorylation, two for rRNAs and 22 for tRNAs) but a gene for ATPase subunit 8 is missing. All genes are transcribed in the same direction. Putative secondary structures of tRNAs indicate that most of them are conventional cloverleaves but the dihydrouridine arm is unpaired in tRNA(Ser(AGN)), tRNA(Ser(UCN)), tRNA(Arg) and tRNA(Cys). The base composition at the wobble positions of fourfold degenerate codon families is highly biased toward U and against C. (C) 2002 Elsevier Science B.V. and Mitochondria Research Society. All fights reserved.

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  • Alveolar echinococcosis: Characterization of diagnostic antigen Em18 and serological evaluation of recombinant Em18 Reviewed

    Y Sako, M Nakao, K Nakaya, H Yamasaki, B Gottstein, MW Lightowers, PM Schantz, A Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   40 ( 8 )   2760 - 2765   2002.8

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    The Echinococcus multilocularis protein Em18 is one of the most promising antigens for use in serodiagnosis of alveolar echinococcosis in human patients. Here we identify an antigenic relationship between Em18 and a 65-kDa immunodominant E. multilocularis surface protein previously identified as either EM10 or Em11/3. The NH2-terminal sequence of native Em18 was determined, revealing it to be a fragment of EM10. Experiments were undertaken to investigate the effect of proteinase inhibitors on the degradation of EM 10 in crude extracts of E. multilocularis protoscoleces. Em18 was found to be the product of degradation of EM10 by cysteine proteinase. A recombinant Em18 (RecEm18, derived fro M K-349 to K-508 of EM10) was successfully expressed by using Escherichia coli expression system and then evaluated for use in serodiagnosis of alveolar echinococcosis. RecEm18 was recognized by 27 (87.1%) and 28 (90.3%) of 31 serum samples from clinically and/or pathologically confirmed alveolar echinococcosis patients by enzyme-linked immunosorbent assay and immunoblotting, respectively. Of 33 serum samples from cystic echinococcosis patients, 1 was recorded as having a weak positive reaction to RecEm18; however, none of the serum samples which were tested from neurocysticercosis patients (n = 10) or healthy people (n = 15) showed positive reactions. RecEm18 has the potential for use in the differential serodiagnosis of alveolar echinococcosis.

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  • Usefulness of hydatid cyst fluid of Echinococcus granulosus developed in mice with secondary infection for serodiagnosis of cystic echinococcosis in humans Reviewed

    W Mamuti, H Yamasaki, Y Sako, K Nakaya, M Nakao, MW Lightowlers, A Ito

    CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY   9 ( 3 )   573 - 576   2002.5

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    The aim of this work was to assess the usefulness of hydatid cyst fluid (HCF) of Echinococcus granulosus, obtained from mice experimentally infected with hydatid cyst tissue homogenates, for the serodiagnosis of cystic echinococcosis (CE) in humans. The sensitivity and specificity of HCF obtained from mice for the detection of immunoglobulin G (IgG) antibodies in the sera of CE patients were compared with those of HCF from sheep and/or from a human CE patient by using immunoblotting (IB) and an enzyme-linked immunosorbent assay (ELISA). HCFs obtained from three different host species all were highly useful for immunoblotting, and sera from 19 (95%) of 20 CE patients equally recognized the antigen B subunit (approximately 8 kDa). HCF from mice showed a cross-reaction with 9 of 20 alveolar echinococcosis (AE) sera (45%), whereas HCFs from two other host species cross-reacted with 14 of the AE sera (70%). Although 2 (10%) of 20 sera from neurocysticercosis (NCC) patients were false positive with HCF from both sheep and humans, none of these sera showed a positive reaction with HCF from mouse origin. ELISAs with HCFs from both mouse and sheep origins detected all 20 CE and AE sera; however, these ELISAs showed 45% (9 of 20) and 60% (12 of 20) false-positive reactions with 20 NCC sera, respectively. The presence of nonspecific human IgG in HCF obtained from a CE patient prevented us from applying it to the ELISA. HCF of E. granulosus, obtained from laboratory mice with a secondary infection with hydatid cyst tissue homogenates, appears to be highly useful for the serodiagnosis of CE in humans and may be useful in domestic animals.

    DOI: 10.1128/CDLI.9.3.573-576.2002

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  • Dogs as alternative intermediate hosts of Taenia solium in Papua (Irian Jaya), Indonesia confirmed by highly specific ELISA and immunoblot using native and recombinant antigens and mitochondrial DNA analysis Reviewed

    A. Ito, M.I. Putra, R. Subahar, M.O. Sato, M. Okamoto, Y. Sako, M. Nakao, H. Yamasaki, K. Nakaya, P.S. Craig, S.S. Margono

    Journal of Helminthology   76 ( 4 )   311 - 314   2002

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    DOI: 10.1079/JOH2002128

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  • Differential serodiagnosis for alveolar echinococcosis by Em18-immunoblot and Em18-ELISA in Japan and China Reviewed

    A Ito, Y Sako, Y Ishikawa, M Nakao, K Nakaya, H Yamasaki

    CESTODE ZOONOSES: ECHINOCOCCOSIS AND CYSTICERCOSIS   341   147 - 155   2002

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    We have analyzed the ongoing surveillance system for alveolar echinococcosis (AE) in Hokkaido and known that the system has three steps. The first step is mass screening by ELISA using crude antigens. The second is image analysis using ultrasonography and CT scan for those selected from the primary screening and immunoblot using crude antigens. The third is surgical resection of the lesion. This system has contributed to detect some early stage of AE and establish curative surgical treatment. It has based on the advances in image analysis and improvement of the surgery. The number of AE patients confirmed through the surveillance system is much less than that confirmed at outpatient hospitals with suspicion of malignant tumor or AE. Official confirmation of AE is based on pathological confirmation of AE after surgical resection of the lesion, either AE or malignant tumor suspected. Therefore, the official report on the new AE patients every year is absolutely underestimated due to the lack of the system for serological confirmation of AE without surgery. In order to establish a better resolution for the control of AE in Hokkaido or in Japan, we need to obtain real information on the incidence of AE with or without surgical confirmation. It is essential to introduce a new system of serological confirmation of AE, since the ongoing serology has been established for the purpose of grasping the outlines of risky population but not for identification of AE patients, Under the new Law "Concerning Prevention of Infectious Diseases and Medical Care for Patients of Infections" in Japan, it is the key to identify A-E cases serologically. We expect that it is possible if we introduce Em18-immunoblot or Em18-ELISA for the mass screening. It is expected to be highly useful not only in Japan but also in China and other countries.

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  • Neurocysticercosis in Asia: Serology/seroepidemiology in humans and pigs Reviewed

    A Ito, Y Sako, M Nakao, K Nakaya

    CESTODE ZOONOSES: ECHINOCOCCOSIS AND CYSTICERCOSIS   341   25 - 31   2002

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    Neurocysticercosis (NCC) is one of the emerging and re-emerging parasitic diseases worldwide. Serodiagnosis for detection of NCC has greatly advanced during the last one decade, We show (i) the critical difference in quality of antigens between intact cyst and cyst fluid, (ii) how to prepare the specific glycoproteins, (iii) sero-epidemiological study in Irian Jaya (West Papua), Indonesia and in Papua New Guinea, (iv) usefulness of the glycoproteins for both ELISA and immunoblot in both humans and pigs and (v) comparison of the sensitivity and specificity of a recombinant antigen and native glycoproteins. (i) It is essential to use cyst fluid for purification of glycoproteins using preparative isoelectric focusing (IEF). (ii) A single step of IEF is sufficient for preparation of antigens available for immunoblot analysis and fractions of pH 8.3 - 9.3 are suitable for immunoblot analysis. However, we better do IEF once again using. the fractions of pH 8.3 - 9.3 for preparation of them suitable for ELISA. (iii) NCC is one of the most serious and highly endemic (pandemic) in Irian Jaya. Approximately 65 -67 % of local people with anamnesis of epileptic seizures or headache (suspected NCC or subcutaneous or muscle nodule(s) (suspected subcutaneous cysticercosis) were serologically confirmed to have been exposed to Taenia solium eggs. Even 26 % of the healthy people at risk were confirmed serologically to have been exposed to T solium eggs. There is some critical serological evidence that NCC is spreading in PNG (other than Irianese refugee). (iv) Approximately 80 % of pigs suspected to be infected with T solium cysts by tongue examination were serologically confirmed, whereas 34-36 % of those suspected to be uninfected were serologically positive by both immunoblot and ELISA. (v) Serology using a recombinant antigen is highly specific but approximately 89% of NCC cases detected using the antigens purified by IEF are detectable.

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  • A phylogenetic hypothesis for the distribution of two genotypes of the pig tapeworm Taenia solium worldwide Reviewed

    M. Nakao, M. Okamoto, Y. Sako, H. Yamasaki, K. Nakaya, A. Ito

    Parasitology   124 ( 6 )   657 - 662   2002

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    DOI: 10.1017/S0031182002001725

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  • Comparison of the antigenicity of protoscoleces and microvesicles of Echinococcus multilocularis prepared from rats Reviewed

    A Ito, T Kanazawa, M Nakao, Y Sako, Y Ishikawa, K Nakaya

    JOURNAL OF HELMINTHOLOGY   75 ( 4 )   355 - 358   2001.12

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    Rats are known to be relatively resistant to infection with Echinococcus multilocularis. However, when rats are inoculated with the parasite tissues, E. multilocularis proliferates slowly at first but after 6 months the cysts increase in size considerably and contain large numbers of protoscoleces: As rats survive for 18 months or longer, approximately 100 ml of packed protoscoleces can be produced from each rat. A comparison of the antigenicity of the protoscoleces and microvesicles by immunoblot methods showed that both Em18 and Em16 are shared components between both protoscoleces and microvesicles, although the latter have some additional antigenic components. In antigens prepared from protoscoleces, the banding patterns around Em18 were much simpler than those from microvesicles. Therefore, for serodiagnosis of E. multilocularis, antigens should be carefully prepared from protoscoleces rather than microvesicles from the rat.

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  • Molecular variation of Taenia solium in the world Reviewed

    M. Okamoto, M. Nakao, Y. Sako, A. Ito

    Southeast Asian Journal of Tropical Medicine and Public Health   32 ( SUPPL. 2 )   90 - 93   2001

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  • NOD-scid mouse as an experimental animal model for cysticercosis Reviewed

    Akira Ito, Kazuhiro Nakaya, Yasuhito Sako, Minoru Nakao, Mamoru Ito

    Southeast Asian Journal of Tropical Medicine and Public Health   32 ( 2 )   85 - 89   2001

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    The major three species of human taeniid cestodes, Taenia solium. T. saginata and T. saginata asiatica (= T. asiatica) which require humans as the definitive host are still not rare in developing countries. Among these, T. solium is the most serious with medical and economic importance. Neurocysticercosis (NCC) in humans is now recognized as the major cause of neurologic disease in the world. As these human taeniid cestodes obligatory require domestic animals such as swine, cattle and swine as the major intermediate host animals respectively, it is not easy to analyze the basic research in these domestic animals. In this brief review, we introduce experimental animal model for these three species in order to obtain fully developed metacestode stage in severe combined immunodeficiency (scid) mice. Non-obese diabetic scid (NOD-scid) mice are expected to be a satisfactory animal model and to have advantages for analysis by several view points of developmental biology with gene expression throughout development, antigenic homology of cyst fluid of these three species, evaluation of drug efficacy or metacestocidal drug designs, confirmation of unknown taeniid gravid segments for identification based on the morphology and DNA analysis of metacestodes. The animal model is not only available for human Taenia spp but can also be applied to other taeniid cestodes of economic importance or in veterinary parasitology.

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  • Resurgence of cases of epileptic seizures and burns associated with cysticercosis in Assologaima, Jayawijaya, Irian Jaya, Indonesia, 1991-95 Reviewed

    T Wandra, R Subahar, GM Simanjuntak, SS Margono, T Suroso, M Okamoto, M Nakano, Y Sako, K Nakaya, PM Schantz, A Ito

    TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE   94 ( 1 )   46 - 50   2000.1

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    Historically, neurocysticercosis (NCC) caused by the larval stage, cysticercus or cysticerci, of the pork tapeworm Taenia solium was recognized in Paniai District, western Irian Jaya Province, Indonesia, in the early 1970s. In the 1990s, we observed a rapid increase in the number of cases of epileptic seizures and burns in Assologaima Sub-District, Jayawijaya District, eastern Irian Jaya. There were totals of 1120 new cases of burns and 293 new cases of epileptic seizures during 1991-95 in Assologaima where the number of inhabitants was 15939. Histopathological examination of resected cysts from patients and a pig revealed that they were cysticerci of T. solium. DNA analysis of these cysts revealed that the nucleotide sequences of 391 base-pair fragments of the mitochondrial cytochrome c oxidase subunit 1 gene were exactly the same in those from patients and the pig. Although 3 of 391 base-pair fragments might differ from that of T. solium reported previously, there were no differences in the amino-acid sequences. Approximately 67% and 65% of persons with epileptic seizures and with subcutaneous nodules, respectively, showed antibody responses highly specific to cysticercosis. Therefore, most cases of epileptic seizures and burns were considered to be associated with cysticercosis in Irian Jaya.

    DOI: 10.1016/S0035-9203(00)90433-4

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Books

  • コンパクト微生物学(寄生虫)

    迫 康仁( Role: Sole author)

    南江堂  2021.3 

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  • シンプル微生物学(原虫学・蠕虫学)

    迫 康仁( Role: Sole author)

    南江堂  2018.3 

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  • エキノコックス症(単包条虫症、多包条虫症)

    迫 康仁( Role: Sole author)

    医薬ジャーナル社  2016.2 

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  • 有鉤嚢虫症の免疫検査抗原の簡便な精製法

    迫 康仁, 岡本宗裕, 伊藤 亮( Role: Joint author)

    三恵社  2014 

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  • 臨床検査ガイド:抗エキノコックス抗体

    伊藤 亮, 迫 康仁( Role: Joint author)

    文光堂  2013.3 

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  • Loop-mediated isothermal amplification method for a differential identification of human taenia tapeworms.

    Sako Y., Nkouawa A., Yanagida T., Ito A.( Role: Joint author)

    Humana Press  2013 

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  • 教科書には載っていない 臨床検査Q&A::糞便中の寄生虫の核酸検査法について教えてください

    迫 康仁, 伊藤 亮( Role: Joint author)

    医学書院  2012.10 

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  • Chapter Echinococcus and Echinococcosis. In: Molecular Detection of Human Parasitic Pathogens (ed. by Liu D)

    Ito A., Nakao M., Sako Y., Yanagida T., Nakaya K., Knapp J., Ishikawa Y.( Role: Joint author)

    CRC Press  2012 

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  • Chapter 62. Taeniasis. In: Molecular Detection of Foodbone Pathogens (ed, Liu D)

    Ito A., Nakao M., Sako Y., Nakaya K., Okamoto M., Yanagida T.( Role: Joint author)

    CRC press  2010.9 

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MISC

  • Echinococcosis: serological detection of patients and molecular identification of parasites

    Akira Ito, Minoru Nakao, Yasuhito Sako

    FUTURE MICROBIOLOGY   2 ( 4 )   439 - 449   2007.8

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    Alveolar (AE) and cystic echinococcosis (CE) are two of the most dangerous helminthic zoonoses worldwide, representing chronic hepatic diseases, often with lethal outcome. Since early diagnosis of echinococcosis is essential for effective treatment, an overview of serological methods for the detection of echinococcosis and differentiation between AE and CE is given. Recombinant antigens Em 18 and Antigen B8/1 are highly recommended for patient screening and identification of AE and CE, respectively, in combination with imaging techniques. Novel aspects of molecular phylogenetic studies on the genus Echinococcus will also be addressed, including the description of Echinococcus shiquicus as a new sister-species of Echinococcus multilocularis. Both the serological detection of the disease and molecular phylogeny will be discussed in perspective.

    DOI: 10.2217/17460913.2.4.439

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  • Evaluation of tongue inspection and serology for diagnosis of Taenia solium cysticercosis in swine: Usefulness of ELISA using purified glycoproteins and recombinant antigen

    M. O. Sato, H. Yamasaki, Y. Sako, M. Nakao, K. Nakaya, A. Plancarte, A. A. Kassuku, P. Dorny, S. Geerts, W. Benitez-Ortiz, Y. Hashiguchi, A. Ito

    Veterinary Parasitology   111 ( 4 )   309 - 322   2003.2

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    Evaluation of serology using glycoproteins (GPs) purified by preparative isoelectric focusing (pH 8.8) and recombinant chimeric antigen (RecTs) of Taenia solium was carried out using (1) blood samples on filter papers from pigs infected with different doses of eggs of T. solium in Mexico, (2) serum samples from pigs found infected naturally in Vietnam and Ecuador and (3) serum samples from pigs suspected to be infected with T. solium by tongue inspection in Tanzania. Antibody responses (IgG) were detectable in experimentally infected pigs confirmed harbouring 16 or more cysts at necropsy from 30 days after egg inoculation. One of three pigs naturally infected and harbouring 2.5 cysts/kg muscle and most of pigs harbouring=5.0 cysts/kg were also seropositive by ELISA. Although pigs may be infected with other taeniid species such as Taenia hydatigena, pigs harbouring this parasite were negative in ELISA. Approximately, 76 and 78% of sera from pigs having nodule(s) in the tongue (positive tongue inspection) were serologically positive by both ELISA and immunoblot, respectively. Furthermore, approximately 34 and 18% of sera from pigs having no nodules in the tongue (negative tongue inspection) were also seropositive by ELISA and immunoblot, respectively. ELISA using the two antigens was more sensitive than immunoblot and reliable for differentiation of pigs infected with cysticerci of T. solium from those either uninfected or infected with other taeniid species. Pigs without nodule by tongue inspection should be checked serologically in endemic areas. © 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-4017(02)00383-7

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  • Taenia solium infection in Irian Jaya (West Papua), Indonesia: a pilot serological survey of human and porcine cysticercosis in Jayawijaya District

    R Subahar, A Hamid, W Purba, T Wandra, C Karma, Y Sako, SS Margono, PS Craig, A Ito

    TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE   95 ( 4 )   388 - 390   2001.7

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  • Mitochondrial genetic code in cestodes

    M Nakao, Y Sako, N Yokoyama, M Fukunaga, A Ito

    MOLECULAR AND BIOCHEMICAL PARASITOLOGY   111 ( 2 )   415 - 424   2000.12

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    The flatworm mitochondrial genetic code, which has been used for all species of the Platyhelminthes, is mainly characterized by AUA codon for isoleucine, AAA codon for asparagine and UAA codon for tyrosine. In eight species of cestodes (Echinococcus multilocularis, Echinococcus granulosus, Taenia solium, Taenia saginata, Taenia hydatigena, Taenia crassiceps, Hymenolepis nana and Mesocestoides corti), the cytochrome c oxidase subunit I (COI) genes were partially sequenced to verify this genetic code. Comparison of the COI-encoding nucleotide sequences with those of human, sea urchin, fruit fly, nematode and yeast indicated that the assignments of AUA and AAA codons are adequate for cestodes. In addition, the nucleotide sequences of ATPase subunit 6 (ATP6) gene and its flanking region were compared to examine initiation and stop codons. In the related species of T. solium and T. saginata, the deduced amino acid sequences of ATP6 were homogeneous; however, the conversion of initiation codon AUG into GUG was observed in T. saginata. We also found the similar conversion in T. classiceps. The C-terminal sequences of putative ATP6 proteins were highly conserved among the eight species and the stop codon UAG was altered to UAA in all Taenia species. The features of the gene-junctional region between NADH dehydrogenase subunit 4 (ND4) and glutamine tRNA (tRNA(Gln)) genes also supported that UAA serves as a stop codon. Based on these results, we propose that the flatworm mitochondrial code should be modified for cestodes, particularly, in an initiating methionine codon (GUG) and a terminating codon (UAA). (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0166-6851(00)00334-0

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  • Molecular characterization and diagnostic value of Taenia solium low-molecular-weight antigen genes

    Y Sako, M Nako, T Ikejima, XZ Piao, K Nakaya, A Ito

    JOURNAL OF CLINICAL MICROBIOLOGY   38 ( 12 )   4439 - 4444   2000.12

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    Neurocysticercosis (NCC) caused by infection with the larvae of Taenia solium is an important cause of neurological disease worldwide. In order to establish an enzyme-linked immunosorbent assay (ELISA) for this infection using recombinant proteins, we carried out molecular cloning and identified four candidates as diagnostic antigens (designated Ag1, Ag1V1, Ag2, and Ag2V1), Except for Ag2V1, these clones could encode a 7-kDa polypeptide, and Ag2V1 could encode a 10-kDa polypeptide. All of the clones were very similar. Except for Ag2V1, recombinant proteins were successfully expressed using an Escherichia coli expression system. Immunoblot analysis of NCC patient sera detected recombinant proteins, but because reactivity to recombinant Ag1 was too weak, Ag1 was not suitable as an immunodiagnostic antigen. So, Ag1V1 and Ag2 were chosen as ELISA antigens, and the Ag1V1/Ag2 chimeric protein was expressed. Of 49 serum samples from NCC patients confirmed to be seropositive by immunoblot analysis, 44 (89.7%) were positive by ELISA. No assays of serum samples from patients with other parasitic infections recognized the Ag1V1/Ag2 chimeric protein. The Ag1V1/Ag2 chimeric protein obtained in this study had a high value for differential immunodiagnosis.

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  • Neurocysticercosis and echinococcosis in Asia: Recent advances in the establishment of highly reliable differential serodiagnosis for international collaboration

    Akira Ito, M. Nakao, Y. Sako, K. Nakaya

    Southeast Asian Journal of Tropical Medicine and Public Health   31 ( 1 )   16 - 20   2000

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    Neurocysticercosis (NCC) and echinococcosis, caused by the larval stage of taeniid cestodes, are recognized as major parasitic zoonoses threatening human life worldwide. Cystic echinococcosis (CE), caused by Echinococcus granulosus, has well been known to be more widely distributing in Europe and Asia (Eurasia) than alveolar echinococcosis (AE) caused by E. multilocularis. However, it has recently been found that AE is more widely distributing or spreading in Eurasia. Furthermore, NCC caused by Taenia solium is also spreading in Eurasia. Due to the lack of reliable methodology for diagnosing these zoonotic cestodiases worldwide, prevalence rates of these diseases are extremely underestimated. Our group has been working for the establishment of differential scrodiagnosis and molecular diagnosis of AE, CE and NCC as international collaboration projects sponsored by the Ministry of Education. Japan from 1994 until 2000 at least. In this paper, we introduce (1) the most recent original work on the establishment of differential serodiagnoses of NCC, AE and CE, (2) international collaboration work on epidemiology of these diseases in several countries, and discuss (3) what we can and should do for the control of such global parasitic diseases. It is stressed that international collaboration or cooperation work on the control of parasitic diseases is only successful based on the original scientific contribution of high standard.

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  • Molecular cloning and characterisation of 23-kDa piroplasm surface proteins of Theileria sergenti and Theileria buffeli

    Y Sako, M Asada, S Kubota, C Sugimoto, M Onuma

    INTERNATIONAL JOURNAL FOR PARASITOLOGY   29 ( 4 )   593 - 599   1999.4

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    The cDNA encoding a 23-kDa piroplasm membrane protein (p23) of Theileria sergenti Chitose (C)-type was isolated and its nucleotide sequence was determined. The gene encodes a polypeptide of 223 aa with a 28 residue N-terminal signal sequence and a hydrophobic, valine-rich, C-terminal transmembrane domain, as deduced from its nucleotide sequence. Southern blot hybridisation analysis proved that p23 gene was a single copy gene and had allelic forms of the gene in the parasite population, By PCR, the open reading frames of T. sergenti Ikeda (I)-type and Theileria buffeli (B)-type p23 were amplified from genomic DNA and their nucleotide sequences were also determined. Comparison of C-type sequence with that of I-type and B-type revealed 90.5% and 93.5% sequence similarity, respectively, at the aa level. These results suggest that a conserved molecule in these benign Theileria spp. could be a candidate antigen for the development of an anti-piroplasm vaccine. (C) 1999 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0020-7519(99)00004-1

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  • Cloning of a cysteine proteinase gene of Theileria sergenti

    Y Sako, C Sugimoto, M Onuma

    JOURNAL OF VETERINARY MEDICAL SCIENCE   61 ( 3 )   271 - 273   1999.3

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    A cDNA encoding cysteine proteinase of Theileria sergenti was isolated from a piroplasm cDNA library and its nucleotide sequence was determined. The gene encodes a polypeptide of 402 amino acids with predicted molecular mass of 46.4 kDa. Analysis of the predicted amino acid sequence revealed a number of features common to known cysteine proteinases. Southern blot analysis showed that the cysteine proteinase gene was likely to be a single copy per genome.

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  • Expression of a major piroplasm surface protein of Theileria sergenti in sporozoite stage

    Y Sako, C Sugimoto, M Onuma

    JOURNAL OF VETERINARY MEDICAL SCIENCE   61 ( 3 )   275 - 277   1999.3

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    A 32 kilodalton major piroplasm surface protein (MPSP) is expressed abundantly on the surface of intraerythrocytic piroplasms of Theileria sergenti and is considered to be a candidate antigen for vaccine development against piroplasmosis. In this study, transcripts of MPSP gene were detected in an expression cDNA library prepared from T. sergenti-infected tick salivary glands. Expression of MPSP in the sporozoite stage was also confirmed by immunoblot analysis. Its expression at the sporozoite and intraerythrocytic stages gives scope for possible induction of protective immunity being targeted at both stages by immunization with recombinant MPSP.

    DOI: 10.1292/jvms.61.275

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Presentations

  • 環境DNA手法を用いたフィリピン、レイテ島、エキラン村における日本住血吸虫症の感染リスク評価

    ヴァレンシア ジョセフ, サトウ マルセロ オオタケ, パブロ アーチー, キムソン マリオ, セルバンテス エレノアー, ジズ マリオ, 迫 康仁, サトウ 恵

    第93回日本寄生虫学会大会 

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  • 多包虫由来物質がヒトの肝細胞に及ぼす影響の解明

    伴戸 寛徳, 迫 康仁

    第93回日本寄生虫学会大会 

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    Event date: 2024.3

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  • 環境DNA手法を用いたフィリピン、レイテ島、エキラン村における日本住血吸虫中間宿主Oncomelania hupensis quadrasiのハザードマップ作成

    レヴォルテアド マーク, ジューン, サトウ マルセロ オオタケ, ジズ マリオ, セルバンテス エレノアー, パブロ アーチー, キムソン マリオ, 迫 康仁, サトウ 恵

    第93回日本寄生虫学会大会 

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    Event date: 2024.3

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  • Understanding mechanisms of Toxoplasma gondii stage conversion in human iPSC-derived neurons

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  • Next steps of eDNA towards the control of schistosomiasis International conference

    Maecello Otake Sato, サトウ 恵, 迫 康仁

    国際熱帯医学・マラリア学学会 

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    Event date: 2022.10

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    Venue:バンコク、タイ  

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  • Environmental DNA and risk mapping in schistosomiasis International conference

    Marcello Otake Sato, Megumi Sato, Yasuhito Sako

    International Congress of Parasitology 

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    Event date: 2022.8

    Language:English   Presentation type:Symposium, workshop panel (nominated)  

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  • エキノコックス症と条虫症

    迫康仁

    日本小児科学会北海道地方会第304回例会  日本小児科学会北海道地方会

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    Event date: 2019.2

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:旭川  

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  • 日本海裂頭条虫感染の1症例報告

    工藤裕基, 迫康仁

    第13回日本臨床検査学教育学術大会 

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    Event date: 2018.8

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • バリ島およびニューギニア島における有鉤条虫の遺伝的多様性とその起源

    柳田 哲矢, Swastika Kadek, Dharmawan Noman S., dra Toni, 佐藤 宏, 迫 康仁, 伊藤 亮, 岡本 宗裕

    第85回 日本寄生虫学会大会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 多包虫は宿主の補体活性を阻害する-多包虫セリンプロテアーゼインヒビターのはたらきー

    佐々木 瑞希, 迫 康仁

    第85回 日本寄生虫学会大会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Development of a simple identification of human taenia species by using multiplex LAMP and dot-ELISA

    Nkouawa Agathe, Sako Yaushito

    第84回 日本寄生虫学会大会 

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    Event date: 2015.3

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Diagnostics of Cysticercosis and Taeniasis International conference

    Yasuhito SAKO

    Taeniasis/Cysticercosis Symposium at Udayana University 

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    Event date: 2014.9

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • イムノクロマトグラフィー法による有鉤嚢虫症の血清検査法の開発

    迫 康仁, 福田健太, 小林行治, 伊藤 亮

    第82回日本寄生虫学会大会 

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    Event date: 2013.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京  

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  • Advances in technology for EBM International conference

    Y. Sako, A. Ito

    Joint International Tropical Medicine Meeting 2012 

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    Event date: 2012.12

    Language:English   Presentation type:Symposium, workshop panel (nominated)  

    Venue:Bangkok, Thailand  

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  • Recent advances in immunogiagnosis of cysticercosis International conference

    Y. Sako, A. Ito

    International Symposium on Cestode Zoonoses Controlo 

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    Event date: 2012.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Shanghai, CHina  

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  • イムノクロマトグラフィー法による多包虫の血清検査および経過観察検査について

    迫 康仁, Tappe Dennis, 福田健太, 小林行治, 伊藤園予, Frosch Matthias, Gruner Beate, Kern Peter, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2012.3

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • An immunochromatographic test for the diagnosis and the follow-up of alveolar echinococcosis International conference

    Sako Y Y., Tappe D., Fukuda K., Kobayashi Y., Itoh S., Frosch M., Gruner B., Kern P., Ito A.

    XXIV World Congress of Hydatidology 

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    Event date: 2011.9

    Language:English   Presentation type:Poster presentation  

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  • 有鉤嚢虫症血清診断抗原の簡便な精製法の確立

    Sako Y., Okamoto M., Nakaya K., Ito A.

    日本寄生虫学会総会 

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    Event date: 2011.7

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • An immunochromatographic test for diagnosis of alveolar echinococcosis International conference

    Sako Y., Fukuda K., Kobayashi Y., Ito A.

    45th Annual Japan-USA Joint Conference on Parasitic Diseases 

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    Event date: 2011.1

    Language:English   Presentation type:Oral presentation (general)  

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  • Recent advances in immuno- and molecular-diagnosis of taeniasis and cysticercosis International conference

    Sako Y., Nkouawa A., Ito A.

    Joint International Tropical Medicine Meeting 2010 

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    Event date: 2010.12

    Language:English   Presentation type:Oral presentation (general)  

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  • 多包虫カテプシンB様システインペプチダーゼの性状解析

    迫 康仁, 中尾 稔, 中谷和宏, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2009.3

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Molecular and Biochemical Approaches for Echinococcosis International conference

    Sako Y., Nakaya K., Nakao M., Ito A.

    XVIIth International Congress for Tropical Medicine and Malaria 

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    Event date: 2008.9 - 2008.10

    Language:English   Presentation type:Oral presentation (general)  

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  • 多包虫カテプシンB様システインペプチダーゼの遺伝子クローニング

    迫 康仁, 中尾 稔, 中谷和宏, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2008.4

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 多包虫メタロプロテアーゼの遺伝子クローニング

    迫 康仁, 中谷和宏, 山崎 浩, 中尾 稔, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2007.3

    Language:Japanese   Presentation type:Poster presentation  

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  • 多包虫カテプシンL様システインプロテアーゼの性状解析

    迫 康仁, 山﨑 浩, 中尾 稔, 中谷和宏, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2006.5

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Recombinant Antigens of Serodiagnosis of Cysticercosis and Echinococcosis International conference

    Sako Y., Nakao M., Nakaya K., Yamasaki H., Ito A.

    Taeniasis/Cysticercosis and Echinococcosis International Symposium with Focus on Asia and the Pacific 

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    Event date: 2005.7

    Language:English   Presentation type:Oral presentation (general)  

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  • 多包虫カテプシンL様システインプロテアーゼの遺伝子クローニング

    迫 康仁, 山崎 浩, 中尾 稔, 中谷和宏, 伊藤 亮

    日本寄生虫学会総会 

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    Event date: 2005.4

    Language:Japanese   Presentation type:Oral presentation (general)  

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Industrial property rights

  • 嚢虫症診断用抗原の精製方法(日本)

    迫 康仁, 伊藤 亮

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    Application no:特願2009-96360  Date applied:2009.4

    Announcement no:特開2010-248087A  Date announced:2010.11

    Patent/Registration no:特許第5582521号  Date registered:2014.7 

    Country of applicant:Domestic  

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Awards

  • 第15回日本寄生虫学会奨励賞

    2006.5   日本寄生虫学会  

    迫 康仁

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

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Research Projects

  • 寄生虫症の迅速で高精度な網羅的種鑑別診断法の開発研究

    2024.4 - 2027.3

    基盤研究(C)

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    寄生虫症を正確に診断し病因寄生虫を鑑別することは、「適切で迅速な治療」と「流行状況の把握」のために非常に重要である。しかし、現在の日本では、寄生虫症の正確な診断を行える医療機関は決して多くはないため、適切な治療を開始するまでに時間を要し、また世界的には寄生虫症の正確な診断による流行状況の把握ができていないため、効果的な寄生虫症の予防対策が滞っている。本研究の目的は「寄生虫検査の経験のない人でも迅速かつ簡便に、寄生虫の種を網羅的に鑑別診断でき、かつ社会実装できる高精度なpoint-of-care(POC)診断法」を開発することである。具体的には、ポータブルPCR装置を使用し、さらにポータブル次世代シーケンサーを組み合わせることにより、臨床現場や流行地で使用できる寄生虫の網羅的な種鑑別診断法を開発する。

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  • メコン住血吸虫の撲滅に向けた多面的な融合対策プログラム作成と数理モデルによる感染リスク分析による「最後の一押し!」

    2024.1 - 2027.3

    AMED 

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  • 国内に蔓延する寄生虫症、輸入寄生虫症の対策に資する研究開発

    2023.4 - 2026.3

    AMED 

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  • アジアの住血吸虫症撲滅を目指した革新的ポイント・オブ・ケア検査法ならびに環境汚染監視ツールの開発

    2022.1 - 2025.3

    AMED 

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  • Elucidating transmission dynamics for soil-transmitted helminths based on environmental DNA analysis

    Grant number:21K12269  2021.4 - 2024.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\3,900,000 ( Direct Cost: \3,000,000 、 Indirect Cost:\900,000 )

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  • Development of an innovative differential diagnosis method for diphyllobothriasis and taeniasis

    Grant number:20K08816  2020.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\4,290,000 ( Direct Cost: \3,300,000 、 Indirect Cost:\990,000 )

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  • Development of the detection method for animal cysticercosis and the investigation of the genetic factors for host specificity

    Grant number:15H05261  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Yanagida Tetsuya

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    Grant amount:\16,900,000 ( Direct Cost: \13,000,000 、 Indirect Cost:\3,900,000 )

    In this study, it was aimed to develop the detection method for cysticercosis, caused by Taenia saginata or Taenia asiatica, in cattle and pigs. Field surveys in the endemic areas were conducted using the developed serology, and it revealed the method can detect T. saginata cysticercosis in cattle. Further extensive surveys are needed to examine the sensitivity and specificity of the method, and whether the method can detect T. asiatica cysticercosis in pig.
    It was for the first time directly demonstrated that cattle can be the intermediate host for the hybrid descendant between T. saginata and T. asiatica. This study indicates the possibility that comparative genomics can reveal the genetic factors controlling the host specificity of T. saginata and T. asiatica.

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  • Epidemiological survey of human taeniasis/cysticercosis and animal cysticercosis and development of comprehensive detection method for soil-transmitted helminths.

    Grant number:15H05273  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Sako Yasuhito

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    Grant amount:\15,990,000 ( Direct Cost: \12,300,000 、 Indirect Cost:\3,690,000 )

    Field survey of human taeniasis/cysticercosis and animal cysticercosis has been conducted in Bali, Indonesia. In human survey we could not find cysticercosis sero-positive case but could find six Taenia solium taeniasis patients. In animal survey, we found that pigs had been exposed to Taenia hydatigena infection. Additionally, we demonstrated that the antigen quality for the detection of anti-Taenia adult antibody of taeniasis patient was affected by the taenia adult worm used for antigen preparation. Furthermore, we developed a simple DNA detection test to differentiate human taenia parasites by loop-mediated isothermal amplification in combination with dot enzyme-linked immunosorbent assay.

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  • Studies on proteinases of Echinococcus multilocularis larva for their survival in the host and search for inhibitors

    Grant number:15K08440  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Sako Yasuhito, OKAMOTO Munehiro, SASAKI Mizuki

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    Grant amount:\4,810,000 ( Direct Cost: \3,700,000 、 Indirect Cost:\1,110,000 )

    We analyzed proteinases of Echinococcus multilocularis larva as key molecules on their persistent infection. Large scale preparation of active recombinant enzymes of four cathepsin-like cystein proteinases reported previously by us was not succeeded. However, we identified novel cathepsin L-like cystein proteinase (EmCLP3) and matrix metalloproteinase (EmMMP). We confirmed that both enzyme was expressed at protein level in larval stage. Furthermore, we demonstrated that EmCLP3 had an activity to digest host protein molecules such as IgG, albumin, collagen and fibrobnectin. These results indicated that EmCLP3 involved in the persistent infection of parasite.

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  • 有鉤条虫の比較ゲノム解析に基づく組織指向性の解明および遊離型DNA検査法の開発

    Grant number:14F04103  2014.4 - 2016.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    迫 康仁, NKOUAWA AGATHE, NKOUAWA Agathe

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    Grant amount:\2,300,000 ( Direct Cost: \2,300,000 )

    有鉤嚢虫症はテニア科条虫に属する有鉤条虫の幼虫の寄生に起因し、時に脳に寄生することにより致死的病態を引き起こす。有鉤嚢虫症は、ラテンアメリカでは脳内寄生のみによるものが大多数であるのに対し、アジアでは、脳内と他組織(主に皮下、筋肉)への寄生によるものが通常である。このような病態の差異を生じさせる組織指向性に関して、なぜアメリカ分離株とアジア分離株間で異なっているのか明確な解答は得られていない。そこで、ゲノムの塩基配列を株間で比較することにより、組織指向性を規定する因子の探索を試みた。同時に、血清中の寄生虫由来DNA検出法の確立を試みた。
    有鉤条虫のゲノム塩基配列を決定するために、タイ分離株では約12G、インドネシア分離株では約10Gの塩基配列データを取得することが出来た。アセンブルソフトAbyssならびにVelvetを用いてアセンブルを実施した結果、タイ分離株においては、Abyssでは最長鎖長820,191bp、velvetでは最長鎖長479,322bpの塩基配列が、インドネシア分離株においてはAbyssでは最長鎖長820,084bp、velvetでは最長鎖長479,322bpの塩基配列がアセンブルされた。今回得られた鎖長は短いため、全塩基配列を得るためにはさらなる塩基配列の取得が必要と考えられた。
    有鉤嚢虫感染ブタの血清虫に寄生虫由来のDNAが存在するか否かを確認する必要があるが、有鉤嚢虫感染ブタ血清を日本で調整することはきわめて困難である。そこで、有鉤嚢虫と同様に血管外寄生する条虫である多包虫を用いて、血管外寄生虫由来DNAの血清からの検出を試みた。多包虫が腹腔内に寄生しているマウスから血液を経時的に採取し、血清中の多包虫由来DNAの有無をPCR法にて確認した。その結果、PCRを2回実施することにより、マウス血清からPCR産物を得ることが出来た。

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  • Molecular evolution and co-evolution in Taeniid cestode infections in the world

    Grant number:24256002  2012.4 - 2015.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    ITO Akira, SAKO Yasuhito, NAKAO Minoru, NAKAYA Kazuhiro, YANAGIDA Tetsuya, OKAMOTO Munehiro, OKAMOTO Yoshiharu

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    Grant amount:\44,070,000 ( Direct Cost: \33,900,000 、 Indirect Cost:\10,170,000 )

    The purpose of this project is better understanding of the evolutional aspect of pathogenic Taeniid cestodes infections in the world. All four genotypes of Echinococcus multilocularis have been exclusively confirmed from Russia. Mitochondrial DNA analysis of E. granulosus s. s. (G1) revealed that polymorphism of the gene was prominent in the specimens from the Middle East countries > China > Peru, and provided a hypothesis “The ancestral E. granulosus s.s. emerged in the Middle East”. Another purpose is better understanding of fertilization mechanisms in cestodes. Comparative studies of mitochondrial DNA (1N) and nuclear DNA (2N) genes using the sister species, Taenia saginata and T. asiatica, and the two (Asian and Afro/American) genotypes of T. solium sampled from areas where these species and two genotypes were sympatrically distributed revealed different types of hybrids. So, it is clear that out-crossing occurs in hermaphroditic cestode infections if two or more worms mature.

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  • Development of the quick diagnostic method for identifying Taenia asiatica and Taenia saginata for food safety and analysis of the gene causing the host specificity.

    Grant number:24406011  2012.4 - 2015.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    OKAMOTO Munehiro, SAKO Yasuhito, YANAGIDA Tetsuya, OKAMOTO Yoshiharu, MATSUI Atsushi

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    Grant amount:\17,290,000 ( Direct Cost: \13,300,000 、 Indirect Cost:\3,990,000 )

    Taenia tapeworms collected from humans were examined for the mitochondrial cox1 gene and two nuclear genes, ef1, elp and pold. Phylogenetic analysis revealed that Taenia saginata and Taenia asiatica were once separated into two distinct taxa. On the other hand, some worms showed nuclear-mitochondrial discordance. Those facts indicate that they originated from hybridization between T. saginata and T. asiatica.

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  • 中国で蔓延している人獣共通寄生虫症(嚢虫症)の迅速・簡便な検査法の開発

    2012.4 - 2015.3

    日中医学協会 

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    嚢虫症の迅速かつ簡便な血清検査法の開発

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  • LAMP法によるエキノコックス条虫の迅速検査法の開発および感染源対策への応用

    2012.4 - 2014.3

    財団法人 大山健康財団 

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    エキノコックス条虫のLAMP法を用いた検出法の開発

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  • 難治性寄生虫病に関する遺伝子診断法の開発

    2010.8 - 2011.3

    文部科学省科学技術・学術政策局 

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  • 多包虫症に関する分子、免疫、伝搬生態学的研究

    2010.4 - 2012.3

    独立行政法人日本学術振興会 

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  • アジア・アフリカで流行している人畜共通寄生虫病研究拠点形成(Ⅱ)

    2009.4 - 2010.3

    独立行政法人日本学術振興会 

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  • Speciation of Taeniid cestodes (Echinococcus spp. and Taenia spp.) in the world and co-evolution of the host-parasite relationship

    Grant number:21256003  2009 - 2011

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    ITO Akira, NAKAO Minoru, NAKAYA Kazuhiro, SAKO Yasuhito, YANAGIDA Tetsuya, OKAMOTO Munehiro

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    Grant amount:\38,610,000 ( Direct Cost: \29,700,000 、 Indirect Cost:\8,910,000 )

    Parasitic cestodes, Cestoda, Plathelminthes, have well been known to be hermatophroditic. Self-fertilization is the basic strategy for reproduction biology in cestodes. However, through our most recent studies on mitochondrial (haploid) and nuclear (diploid) DNA of two independent species infecting humans, Taenia saginata and Taenia asiatica have revealed that there are hybrids or hybrid derived adult tapeworms in Thailand and China where these species are sympatrically distributed. These data strongly reveal cross fertilization in the definitive host, humans, and launch “What is T. asiatica? Is it really independent species?" It is still under debates. Similar evidence showing cross fertilization between the intraspecies two, Asian and Afro/American genotypes of Taenia solium has been confirmed from larval stage of this parasite sampled in Madagascar. In Madagascar, we could have confirmed that the two genotypes are sympatrically distributed and also some hybrid individuals have been confirmed. Our work is the first one comparing both mitochondrial and nuclear genes in cestodes or platyhelminthes. These all data strongly suggest the cross fertilization in cestode reproduction biology. Molecular studies on Echinococcus spp. have also revealed that E. granulosus sensu lato is not a single species but 5 species, and a total of 9 independent species are included in the genus Echinococcus. Among these species, E. multilocularis is highly pathogenic and 3 (North American, Asian and European) genotypes have been known, but we have confirmed additional one, Mongolian genotype. The new information on the cestode speciation and identification has successfully been confirmed by the establishment of immuno- and molecular-diagnostic tools developed by our research team.

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  • Development of diagnostic methods for domestic animals infected with larval taeniid cestodes and application to risk management.

    Grant number:21406009  2009 - 2011

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    OKAMOTO Munehiro, ITO Akira, ITO Akira, OKAMOTO Yoshiharu

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    Grant amount:\17,550,000 ( Direct Cost: \13,500,000 、 Indirect Cost:\4,050,000 )

    Parasitological survey on human taeniid cestods was don in Tibetan Plateau, Sichuan, China and Bali, Indonesia. In Tibetan Plateau, three human Taenia, Taenia solium, Taenia saginata and Taenia asiatica were endemic sympatorically. In Bali, T. solium was endemic in the northern part of island a d T. saginata was endemic in the southern part. In addition, hybrid between T. saginata and T. asiatica was found in Tibetan Plateau. We examined the molecul ar and immunological diagnostic methods for human taniasis/cysticercosis, which were developed by our research group. We also evaluated the risk of domestic animals for endemic of human taniasis/cysticercosis.

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  • 北海道特有の地方病(特にエキノコックス症等)に関する総合研究及び臨床応用

    2007.8 - 2010.3

    文部科学省研究振興局 

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  • アジア・アフリカで流行している人畜共通寄生虫病研究拠点形成

    2007.4 - 2009.3

    独立行政法人日本学術振興会 

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  • エキノコックス症における寄生虫の発育分化と宿主免疫応答の動的解析

    Grant number:19041009  2007 - 2008

    日本学術振興会  科学研究費助成事業  特定領域研究

    伊藤 亮, 中谷 和宏, 中尾 稔, 迫 康仁, 柳田 哲矢

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    Grant amount:\7,900,000 ( Direct Cost: \7,900,000 )

    エキノコックス症(多包虫症、単包虫症)における1)宿主の免疫応答性解析ならびに2)寄生虫の遺伝子解析、3)新種Echinoccus shiquicusと他のエキノコックスの発育動態比較観察を中心に研究を実施した。1)WHOは多包虫症、単包虫症の病態をそれぞれPNMstage I〜IV, CL〜CE5と定義している。病態が正確に把握されている多数の多包虫症血清、単包虫症血清についてドイツのPKern教授、イタリアのE Brunetti教授の研究グループからそれぞれ提供を受けた。エキノコックス症感染動態とTotal IgGの動態解析を実施し、それぞれ共著論文を作成し、投稿した。RecEm18-ELISAが多包虫症の感染動態を正確に評価できる抗体指標になること、RecAgB8/1-ELISAが単包虫症の感染動態、特に活性病巣を有している症例のほぼ90%を検出できることが判明した。現在は、IgG subclass, IgE応答を解析中である。2)ミトコンドリアならびに核遺伝子を用いるエキノコックス属条虫種の再評価を実施し、アフリカライオンに寄生している種を独立種(Echinococcus felidis)として再記載した。ヨーロッパ、南米、中国に分布しているいわゆる単包条虫(E. granulosus sensu strict)ならびに北半球に分布している多包条虫(E. multilocularis)、中国チベット高原から発見された新種エキノコックス条虫(E. shiquicus)の遺伝子多型を解析し、E. shiquicusが遺伝子多型に富んでいるのに対し、他の2種では地域を問わずほぼ均一の遺伝子型が中心になっていることが判明した。3)E. shiquicus幼虫の形態は他の条虫と大きく異なっていることが判明した。中国に分布しているエキノコックス条虫3種の発育様式の比較、公衆衛生学的に重要な多包虫症、単包虫症の病態と抗体応答のさらなる解析が今後の課題である。

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  • In situ localization of cysteine proteinase of Taenia solium cysticercus

    Grant number:19590423  2007 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\4,550,000 ( Direct Cost: \3,500,000 、 Indirect Cost:\1,050,000 )

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  • Molecular epidemiological survey and risk evaluation of livestock animals for control of taeniasis and cycticercosi s.

    Grant number:18406008  2006 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    OKAMOTO Munwhieo, OKAMOTO Yoshiharu, ITO Akira, SAKO Yasuhito

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    Grant amount:\15,750,000 ( Direct Cost: \13,200,000 、 Indirect Cost:\2,550,000 )

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  • エキノコックス症化学療法剤の標的分子候補としてのシステインプロテアーゼの解析

    Grant number:18790289  2006 - 2007

    日本学術振興会  科学研究費助成事業  若手研究(B)

    迫 康仁

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    Grant amount:\3,400,000 ( Direct Cost: \3,400,000 )

    エキノコックス幼虫システインプロテアーゼを標的分子とする化学療法剤の開発のために必須である、その一次構造を決定し、性状の解析を試みた。本年度は、エキノコックス幼虫カテプシンB様システインプロテアーゼ(EmCtB)に関する解析を行った。
    1.カテプシンB様システインプロテアーゼ遺伝子のクローニング
    システインプロテアーゼの酵素活性部位に高度に保存されたアミノ酸配列を基にプライマーを設計し、エキノコックス幼虫cDNAを鋳型としPCRを行い、システインプロテアーゼ遺伝子の一部分をクローニングした。既にクローニングしてあるシステインプロテアーゼ遺伝子をDNAハイブリダイゼーション法により除去することにより、新規遺伝子をクローニングした。DNA解析の結果、得られたクローンは、カテプシンB様システインプロテアーゼに相同性を示した。また、この遺伝子をEmCtBと命名した。
    2.エキノコックス幼虫での発現解析
    EmCtBに対するモノクローナル抗体を調整し、エキノコックス幼虫抽出抗原および分泌・排泄(ES)液に対してイムノブロット解析を行った結果、抽出抗原およびES抗原で25.6および26.4kDaの蛋白質が検出された。これらの結果より、両酵素が蛋白質レベルで発現していること、また、一部が分泌されていることが明らかとなった。次に、エキノコックス幼虫での局在を解析するために、免疫組織染色を行った。その結果、胚層、繁殖胞および原頭節で発現していることが確認できた。
    3.活性型EmCtBの発現
    活性型酵素を酵母(Pichia pastoris)を用いて発現させた結果、酵素活性を持つ十分量の組換え蛋白質を得ることが出来た。また、組換え酵素は高度に糖付加を受けている事が明らかとなった。

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  • Speciation, pathogenicity and evolution of Echinococcus and Taenia tapeworms in Asia

    Grant number:17256002  2005 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    ITO Akira, NAKAO Minoru, NAKAYA Kazuhiro, SAKO Yasuhito, YANAGIDA Tetsuya, OKAMOTO Munenori

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    Grant amount:\41,860,000 ( Direct Cost: \32,200,000 、 Indirect Cost:\9,660,000 )

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  • Severe Combined Immunodeficient(SCID) Mice As Animal Models for Human Echinococcosis

    Grant number:15500295  2003 - 2004

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    NAKAYA Kazuhiro, YAMASAKI Hiroshi, NAKAO Minoru, SAKO Yasuhito, ITO Akira

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    Grant amount:\3,800,000 ( Direct Cost: \3,800,000 )

    At first, two strains of sever combined immune-deficiency mice, C.B-17/Icr-scid and NOD/Shi-scid were compared with the sensitivity to Echinococcus multilocularis metacestode. At post infection 9 and 12weeks, the developed metacestode of two strains infra peritoneal cavities were weighed and compared. NOD/Shi-scid showed more high degree weight than C.B-17/Icr-scid at both points of weeks. It was suggested that scid-gene, declines of macrophage function and compliment activity were influenced together.
    So, development and growth of metacestode in NOD/Shi-scid were observed in detail. At post infection 1,2,3 weeks, between NOD/Shi-scid and control NOD/Shi-+/+ mice, there were no defferences both weight and morphologies of metacestodes. NOD/Shi-+/+ mice were not revealed for rEm-18 antibody in these periods. It was considered that so-called prepatent period which antibody was not yet producted in host immune system. After post infection 6 weeks, in NOD/Shi-scid mice, multivesiculation and formation of protoscolex were rapidly proceeded. NOD/Shi-scid mice showed striking torelance for the parasite development and growth. It was suggested that NOD/Shi-scid mouse would be a model for human echinococcosis.
    And moreover, it was attempted of quantification of multivesiculation and protoscolex formation of the parasite between NOD/Shi-scid and NOD/Shi-+/+ mice. After post infection 6 weeks, in NOD/Shi-scid mice, index of multivesiculation and protoscolex formation suddenly increased. While in NOD/Shi-+/+ mice, in spite of spread of parasite and inflamated fucus, index of multivesicelation was decreased for not changed number of vesicular. Index of protoscolex also increased more in NOD/Shi-scid mice than in NOD/Shi-+/+ mice. It was expected that index methods of these parasite development or growth was usefullness in evaluation of host sensitivity and drug efficacy, estimate of infectious point.

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  • Immunodiagnosis for echinococcosis: international standardization, early diagnosis and evaluation of prognosis

    Grant number:12557024  2000 - 2002

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ITO Akira, YAMASAKI Hiroshi, NAKAYA Kazuhiro, KOGO Yutaka, NAKAO Minoru, FUJIMOTO Yoshinori

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    Grant amount:\13,300,000 ( Direct Cost: \13,300,000 )

    The main results from this project to identify patients of alveolar echinococcosis (AE) serologically are as followings.
    1. The establishment of a new serodiagnosis for identification of alveolar echinococcosis using a recombinant Em18 (RecEm18) (Sako et al. 2002. Journal of Clinical Microbiology 40, 2769-2765) and affinity-purified Em18 (Xiao et al. submitted for publication) and demonstration that Em18 is the product of degradation of EM10 by cysteine proteinase and has the least homology with human EMR proteins and be expected to have the highest B cell epitope activity among all other candidate protein antigens.
    2. The usefulness of RecEm18 has been evaluated as a blind test with French group (Ito et al. 2002. Journal of Clinical Microbiology 40, 4161-4165). Additional work to confirm AE using RecEm18 has just started with French and Swiss groups.
    3. Serological differentiation of another echinococcosis, cystic echinococcosis (CE) has also been well advanced (Mamuti et al. 2002. Clinical and Diagnostic Laboratory Immunology 9, 573-576). Production of a recombinant Antigen B (RecAgB) has been succeeded (Mamuti et al. in preparation).
    4. Serology to identify neurocysticercosis (NCC) of Taenia solium has been established using a recombinant chimeric antigen (Sako et al. 2000. Journal of Clinical Microbiology 38, 4439-4444).
    5. These serological methods to identify AE, CE and NCC are the best in the world and have been applied for international collaboration projects and have been reviewed in several journals and books.
    6. Molecular work to differentiate Echinococcus species and Taenia species has been established.
    7. We have published 29 original papers, 14 proceedings and 5 chapters in three books in English last three years. To establish rapid system for these serodiagnosis and molecular diagnosis is the next step of our research.

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  • 分子生物学的アプローチによる難治性寄生虫感染症の血清診断法の開発

    Grant number:12770122  2000 - 2001

    日本学術振興会  科学研究費助成事業  奨励研究(A)

    迫 康仁

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    Grant amount:\2,000,000 ( Direct Cost: \2,000,000 )

    新興・再興感染症として世界規模で流行し汚染地域拡大が年々深刻化している人体寄生条虫症の1つである有鉤嚢虫症の高品質な診断用抗原の安定供給とそれを用いた血清診断法の国際標準化を最終的な目的としている。本研究では、前年度に確立した組換え抗原を用いた血清診断法の評価を行うとともに、分離株間の遺伝子多型について解析を行った。
    1)組換え蛋白質を用いた有鉤嚢虫血清診断法の評価
    組換え抗原は、有鉤嚢虫症に対する特異性は十分なものの、感度の点で問題があった。すなわち、有鉤嚢虫の多数寄生の場合は9割近くの特異抗体を検出することができたが、1個体寄生の場合、有鉤嚢虫液より精製した抗原分子を用いた診断では9割近くを陽性と判断できるのに対し、組換え蛋白質では7割前後までにその感度が減少した。抗原蛋白質をコードする遺伝子は多重遺伝子ファミリーを形成していることが明らかとなっているため、更なる遺伝子のクローニングの必要性が示唆された。また、本抗原蛋白質は高度に糖鎖修飾を受けている分子であることから、有鉤嚢虫特異的な糖鎖構造の抗原としての重要性も示唆された。
    2)分離株間の抗原遺伝子多型
    分離株(中国、インドネシア、エクアドル、ペルー)ゲノムDNAより抗原遺伝子をPCRにより増幅し、その遺伝子構造および遺伝子多型について解析した。その結果、抗原遺伝子は3つのエクソンと2つのイントロンを有していた。また、分離株間で極めて高い相同性(98%)を示した。これより、組換え蛋白質を用いた血清診断において熟慮しなければならない分離株間の抗原性の多様性を克服することが出来得ると示唆された。

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  • SERO-AND MOLECULAR-EPIDEMIOLOGICAL STUDY ON ECHINOCOCCOSIS AND CYSTICERCOSIS IN ASIA (2000)

    Grant number:11694259  1999 - 2000

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A).

    ITO Akira, OKAMOTO Munehiro, HORII Toshihiro, KANAZAWA Tamotsu, SAKO Yasuhito, NAKAO Minoru

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    Grant amount:\11,500,000 ( Direct Cost: \11,500,000 )

    Zoonotic larval cestode infections involving echinococcosis and cysticercosis are threatening human life and involved in Emerging/Re-emerging infectious diseases worldwide and the endemic areas are spreading year by year. Echinococcosis has been involved on the category 4 in the new Prevention of Infectious Diseases in Japan from April 1999. However, there is no reliable differential serodiagnosis without surgical confirmation. It is too behind of modern science and technology. My research group members at Asahikawa Medical College (AMC) has already established highly reliable serodiagnoses for differentiation of these three serious parasitic diseases. The serodiagnoses at AMC has been evaluated to be the top level (one of the top two) in the world. There is no false positive case for alveolar echinococcosis (AE) from other diseases at all and it is sound for neurocysticercosis (NCC) too. Therefore, many research groups in the world has contacted with AMC including WHO.Recombinant antigens for serodiagnosis of AE and NCC have been produced at AMC.AMC group has succeeded in the analysis of full length of mitochondrial DNA of Echinococcus multilocularis and Taenia solium, the causative pathogens for AE and NCC, respectively. Therefore, it is expected to establish DNA diagnosis for differentiation of any taeniid cestodes of human origin. AMC group members are now involved in many international collaboration projects on the control of echinococcosis and neurocysticercosis not only in Asia but also in the world. AMC group is expecting to establish the research and reference centers for serodiagnosis and molecular diagnosis for these zoonotic cestodiases in Asia.

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  • MOLECULAR- AND IMMUNO-DIAGNOSIS FOR EMERGING/RE-EMERGING INFECTIOUS DISEASES, ECHINOCOCCOSIS AND CYSTICERCOSIS (1999)

    Grant number:10557029  1998 - 1999

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ITO Akira, NAKAO Minoru, OKAMOTO Munehiro, HORII Toshihiro, SAKO Yasuhito

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    Grant amount:\12,300,000 ( Direct Cost: \12,300,000 )

    Echinococcosis and cysticercosis are most serious zoonotic cestode infections worldwide. The endemic areas are spreading year by year almost all over the world. As these diseases are threatening human life and immuno- and molecular-diagnosis for these diseases are not easy so far examined, we have started to establish better resolution for differential immuno- and molecular-diagnosis as international collaboration projects from 1994. The present research results are highly promising but they are joined good results from the international collaboration projects sponsored by the Ministry of Education, Science, Sports and Culture (11694259). We developed highly reliable serodiagnosis for differentiation of alveolar echinococcosis, cystic echinococcosis and neurocysticercosis using native antigens. Based on huge number of important patients' sera from almost all over the world through WHO informal echinococcosis working group members and others, our serodiagnosis is now evaluated to have the top quality in specificity and sensitivity in the world. The invited paper entitled "Differential serodiagnosis for larval cestode infections: cystic echinococcosis, alveolar echinococcosis and neurocysticercosis" presented by Akira Ito at the 33rd International Congress of Hydatidology held in Argentina September 1999 was nominated as the best paper on echinococcosis in 1999. We further have established recombinant antigens for neurocysticercosis and now are planning to produce recombinant antigens highly useful for alveolar echinococcosis and cystic echinococcosis from 2000 if we can get additional research grant money. We have also analyzed the full length of mitochondrial DNA of Echinococcus multilocularis and Taenia solium. As it is the first success in the world, we have been asked to collaborate for molecular epidemiology of these larval cestode infections in the world.

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  • SEVERE COMBINED IMMUNODEFICIENT (SCID) MICE AS ANIMAL MODELS FOR HUMAN CYSTICERCOSIS AND ECHINOCOCCOSIS (1999)

    Grant number:10480235  1998 - 1999

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ITO Akira, SAKO Yasuhito, NAKAO Minoru, ITO Mamoru, NAKAYA Kazuhiro

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    Grant amount:\10,500,000 ( Direct Cost: \10,500,000 )

    Zoonotic larval cestode infections involving cysticercosis and echinococcosis are involved in Emerging/Re-emerging infectious diseases worldwide. As human taeniid tapeworm infections, we recognize three species : Taenia solium, T. saginata and T. asiatica (= T. sagainata asiatica). As (1) these taeniid cestodes require such domestic animals as cattle and pigs and even humans as the intemediate host and (2) the definitive host is only humans, it is very difficult to analyze the mechanism of the host-parasite relationship. We tried to establish a net-work system for getting viable eggs from any countries in the world at first, and when we could get eggs, we used immunodeficient mice including severe combined inununodeficient (scid) mice, congenitally athymic nude mice, and knock-out mice for experimental infections of taeniid eggs. We found that nonobese diabetic (NOD)-scid mice of both sexes are supreme experimental animal models for cysticercosis of human taeniid cestode infections. It was concluded that four-month-old cysticerci of T. saginata, developed in a NOD-scid mouse were mature ones, since when a volunteer ingested three cysticerci, he got infection. Another topic of our research was that we found unexpected basic life cycle of cestodes in NOD-scid and NMRI-nude mice. Hymenolepis microstoma requires beetles as obligatory intermediate hosts. However, when NMRI-nude and NOD-scid mice were orally given 5 cysticercoids, they harbored many adult tapeworms over the five original ones. We confirmed that oncospheres of H. microstoma could invade the intestinal tissue of these immunodeficient mice and develop into cysticercoids within 11 days. Cysticercoids of H. microstoma remained tailed, beetle-derived ones in these mice, although H. nana, only exceptional cestode to have a direct life cycle in a mouse, develops tailless, mouse-derived one in a mouse. It is now easy for us to analyze these two very important basic researches on immunobiology of cestode infections using NOD-sicd mice.

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  • Development of Serodiagnosis of Parasite Infection

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    Grant type:Competitive

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  • エキノコックス症血清検査法の開発 International coauthorship

    (選択しない) 

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    難治性寄生虫症である多包虫および単包虫症の組換え抗原を用いた、感度の高い特異抗体検出法の開発

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  • 有鉤嚢虫症血清検査法の開発 International coauthorship

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    致死性寄生虫疾患である有鉤嚢虫症の、組換え抗原を用いた感度の高い特異抗体検出法の開発

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  • 条虫-宿主の分子間クロストークの解明

    (選択しない) 

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    条虫幼虫の宿主での生存戦略としての分子間クローストークの解明。特に、膜蛋白質および分泌蛋白質の活性についての解析。

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  • 多包虫蛋白質分解酵素の解析

    (選択しない) 

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    多包虫の分子標的治療薬開発のための、寄生虫蛋白質分解酵素の性状解析

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  • 寄生虫感染症の血清診断法の開発

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    Grant type:Competitive

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  • 条虫DNA検出に基づく鑑別検査法の開発 International coauthorship

    (選択しない) 

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    マルチプレックスPCR法ならびにLAMP法を用いた条虫DNA検出に基づく条虫種鑑別検査法の開発。特に、糞便を検体とした検出法の開発。

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  • JICA 地域保健担当官のための保健行政研修 脳嚢虫症・エキノコックス症

    2015.7

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    平成27年7月1日(水) 旭川医科大学 アフリカ地域9カ国

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  • JICA 地域保健担当官のための保健行政 講義 脳嚢虫症・エキノコックス症

    2014.7

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    平成26年7月7日(月) 旭川医科大学 アフリカ地域 8カ国

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  • 北海道感染症危機管理対策協議会 委員

    2014.1

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    平成29年9月8日 会議出席
    平成31年3月27日 会議出席
    令和2年9月 メール会議

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