Browsing by Author "Munehiro Okamoto"

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    Evidence of hybridization between Taenia saginata and Taenia asiatica
    (2010-03-01) Munehiro Okamoto; Minoru Nakao; David Blair; Malinee T. Anantaphruti; Jitra Waikagul; Akira Ito; Faculty of Agriculture; Asahikawa Medical University; James Cook University, Australia; Mahidol University
    There has long been a debate as to the specific status of the cestode Taenia asiatica, with some people regarding it as a distinct species and some preferring to recognize it as a strain of Taenia saginata. The balance of current opinion seems to be that T. asiatica is a distinct species. In this study we performed an allelic analysis to explore the possibility of gene exchange between these closely related taxa. In total, 38 taeniid tapeworms were collected from humans living in many localities including Kanchanaburi Province, Thailand where the two species are sympatric. A mitochondrial DNA (mtDNA)-based multiplex PCR tentatively identified those parasites as T. asiatica (n = 20) and T. saginata (n = 18). Phylogenetic analyses of a mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and two nuclear loci, for elongation factor-1 alpha (ef1) and ezrin-radixin-moesin (ERM)-like protein (elp), assigned all except two individual parasites to the species indicated by multiplex PCR. The two exceptional individuals, from Kanchanaburi Province, showed a discrepancy between the mtDNA and nuclear DNA phylogenies. In spite of their possession of sequences typical of the T. saginata cox1 gene, both were homozygous at the elp locus for one of the alleles found in T. asiatica. At the ef1 locus, one individual was homozygous for the allele found at high frequency in T. asiatica while the other was homozygous for the major allele in T. saginata. These findings are evidence of occasional hybridization between the two species, although the possibility of retention of ancestral polymorphism cannot be excluded. © 2009 Elsevier Ireland Ltd. All rights reserved.
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    The first workshop towards the control of cestode zoonoses in Asia and Africa
    (2011-06-23) 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; Asahikawa Medical University; Kyoto University; Sichuan Provincial CDC; Ministry of Health, Republic of Indonesia; Universitas Udayana; Mahidol University; Ministry of Health; Health Science University of Mongolia; Haramaya University; University of Helsinki Haartman Institute
    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. © 2011 Ito et al; licensee BioMed Central Ltd.
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    Genotypic relationships between taenia saginata, taenia asiatica and their hybrids
    (2013-11-01) Kanako Yamane; Tetsuya Yanagida; Tiaoying Li; Xingwang Chen; Paron Dekumyoy; Jitra Waikagul; Agathe Nkouawa; Minoru Nakao; Yasuhito Sako; Akira Ito; Hiroshi Sato; Munehiro Okamoto; Yamaguchi University; Asahikawa Medical University; Centers for Disease Control and Prevention; Mahidol University; Kyoto University
    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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    Molecular and serological survey on taeniasis and cysticercosis in Kanchanaburi Province, Thailand
    (2010-09-01) Malinee T. Anantaphruti; Munehiro Okamoto; Tippayarat Yoonuan; Surapol Saguankiat; Teera Kusolsuk; Megumi Sato; Marcello O. Sato; Yasuhito Sako; Jitra Waikagul; Akira Ito; Mahidol University; Asahikawa Medical University; Tottori University
    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 (<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 (>1 year) history of expelling proglottids in the stool. © 2010.
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    Risk factors and prevalence of taeniasis among the Karen people of Tha Song Yang District, Tak Province, Thailand
    (2021-01-01) Teera Kusolsuk; Kittipong Chaisiri; Akkarin Poodeepiyasawad; Surapol Sa-Nguankiat; Nirundorn Homsuwan; Tetsuya Yanagida; Munehiro Okamoto; Dorn Watthanakulpanich; Jitra Waikagul; Paron Dekumyoy; Chalit Komalamisra; Akira Ito; Faculty of Tropical Medicine, Mahidol University; Primate Research Institute; Asahikawa Medical University; Joint Faculty of Veterinary Medicine
    Taeniasis remains a prevalent public health problem in Thailand. National helminthiasis surveys report only the incidence of Taenia spp. eggs. The ability to differentiate Taenia species using morphological and molecular techniques is vital for epidemiological surveys. This study detected taeniasis carriers and other helminthic infections by Kato's thick smear technique and identified the Taenia species by multiplex PCR. The study subjects were the ethnic Karen people in Tha Song Yang District, Tak Province, Thailand, bordering Myanmar. In total, 983 faecal samples from villagers were examined for helminthiases. Interview-based questionnaires were used to gather information on possible risk factors for infection. The prevalence of helminth infections was 42.7% (420/983), including single (37.3%, 367/983) and mixed infections (5.4%, 53/983). The most common infection (19.23%, 189/983) was Ascaris lumbricoides, whereas taeniasis carriers comprised 2.8% (28/983). Multiplex PCR of Cox1 was used for species identification of Taenia tapeworms, eggs, or both in 22 taeniasis carriers. Most of the parasites (20 cases) were Taenia solium, with two cases of Taenia saginata. Taenia saginata asiatica was not found in the villagers examined. The analysis of 314 completed questionnaires showed that a statistically significant (p < 0.05) risk of taeniasis was correlated with being male, a history of being allowed to forage during childhood, a history of seeing tapeworm proglottids, and a history of raw or undercooked pork consumption. Health education programmes must seek to reduce and prevent reinfection in these communities.
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    Sympatric occurrence of Taenia solium, T. saginata, and T. asiatica, Thailand
    (2007-01-01) 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; Mahidol University; Asahikawa Medical University; Universidade Federal do Tocantins; Tottori University
    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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    Taenia solium, Taenia saginata, Taenia asiatica, their hybrids and other helminthic infections occurring in a neglected tropical diseases' highly endemic area in Lao PDR
    (2018-02-08) 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; Niigata University; Yamaguchi University; Mahidol University; Nagasaki University; Kyoto University; Asahikawa Medical University; Dokkyo Medical University; Station of Malariology; Ministry of Health
    © 2018 Sato et al. 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.
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    Taeniasis and cysticercosis in Asia: A review with emphasis on molecular approaches and local lifestyles
    (2019-10-01) Akira Ito; Tiaoying Li; Toni Wandra; Paron Dekumyoy; Tetsuya Yanagida; Munehiro Okamoto; Christine M. Budke; Texas A&M College of Veterinary Medicine & Biomedical Sciences; Center for Human Evolution Modeling Research; Universitas Sari Mutiara Indonesia; Centers for Disease Control and Prevention; Yamaguchi University; Mahidol University; Asahikawa Medical University
    © 2019 Elsevier B.V. Taeniasis is an important parasitic condition in Asia, especially since all three human-infecting Taenia spp., Taenia solium, Taenia saginata, and Taenia asiatica are found in this region. These three species are believed to be sympatrically distributed, with the largest disease burden found in remote and rural areas where people raise pigs and cattle in a traditional manner. Recent studies revealed that T. asiatica and T. saginata are genetically-related sister species that are not completely reproductively isolated from each other. Current evidence indicates that most T. asiatica adult worms are hybrid-derived descendants. Moving forward, nuclear DNA analysis will be critical in further assessing the species circulating locally. Lifestyle choices, such as the consumption of undercooked meat, are important in maintaining the life cycles of these parasites. In addition, poor hygiene and sanitation, in highly endemic areas, make disease control difficult, resulting in the need for sustainable education programs. An overview of the present situation of taeniasis and cysticercosis in Asia is provided, followed by a discussion of molecular approaches to species assessment and the impact of human lifestyles on parasite transmission.