Curriculum Vitaes

Toshihiro Tokiwa

  (常盤 俊大)

Profile Information

Affiliation
Associate Professor, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University
Degree
博士(医学)(東京医科歯科大学)

Contact information
tokiwanvlu.ac.jp
J-GLOBAL ID
201501020518472949
researchmap Member ID
B000247236

【寄生虫検査技術講習会】

自治体(動物愛護センター等)や獣医療施設にて、獣医療関係者を対象とした寄生虫検査技術講習会を実施しています。ご相談、ご依頼などは上記連絡先までお問合せください。

 

【寄生虫データベース】

・奄美大島・徳之島の野生動物の寄生虫リスト 【ここをクリック(googleに接続します)】 


Education

 1

Awards

 3

Papers

 53
  • Ayaka Kitajima, Toshihiro Tokiwa, Kandai Doi, Kaito Kotani, Hiroko Otsubo, Chinatsu Kamei, Hiromitsu Hitani, Toshiaki Yamamoto, Takuya Kato
    102 102913, Oct, 2024  Peer-reviewedLead authorCorresponding author
  • Toshihiro Tokiwa, Momo Fushimi, Shyun Chou, Akemi Yoshida, Kensei Kinoshita, Atsushi Hikima, Taisei Kikuchi, Kiyokazu Ozaki
    BMC Veterinary Research, 20 148, Apr, 2024  Peer-reviewedLead authorCorresponding author
  • Toshihiro Tokiwa, Kengo Ueda, Nagi Watanabe, Shyun Chou, Kiyokazu Ozaki
    International Journal for Parasitology: Parasites and Wildlife, 23 100920, Mar, 2024  Peer-reviewedLead authorCorresponding author
  • Masaki Murakami, Toshihiro Tokiwa, Hiromu Sugiyama, Mitsuko Shiroyama, Yasuyuki Morishima, Sota Watanabe, Takato Sasamori, Mami Kondo, Tsutomu Mano, Hifumi Tsuruga
    International Journal for Parasitology: Parasites and Wildlife, 21 264-268, Jul, 2023  Peer-reviewedLead authorCorresponding author
  • Shyun Chou, Takashi Mohri, Toshihiro Tokiwa
    Journal of Exotic Pet Medicine, 46 25-26, Apr, 2023  Peer-reviewedLast authorCorresponding author
  • Kandai Doi, Toshihiro Tokiwa, Miyu Imoto, Shyun Chou, Fumiaki Yamasaki, Takuya Kato, Shin-ichi Hayama
    Parasites & Vectors, 16(1) 116, Mar, 2023  Peer-reviewedLead authorCorresponding author
    Abstract Background The oriental eyeworm Thelazia callipaeda (Spirurida: Thelaziidae) is an emerging parasitic ocular nematode of carnivores and humans. In domestic animals and humans, the infection causes varying degrees of inflammation and lacrimation, and wild carnivores represent an important reservoir. In this study we examined the infection status and molecular characterization of T. callipaeda in two urban carnivores, raccoons Procyon lotor and wild Japanese raccoon dogs Nyctereutes viverrinus, in the Kanto region of Japan. Methods From January 2020 to December 2021, 193 carcasses including 178 raccoons and 15 raccoon dogs were examined for the presence of worms in the eye. The worms from infected animals (one worm per host) were morphologically identified as T. callipaeda. Worms (1–5 worms per host) were subjected to genetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences. Results The prevalence of T. callipaeda in raccoons and Japanese raccoon dogs was 20.2% (36/178) and 13.3% (2/15), respectively. The cox1 sequences from 56 worms from 38 animals revealed three haplotypes (h9, h10, and h12). Analysis of multiple worms for five raccoons showed co-infection of two different haplotypes (h9 and h10) in a single host. Comparing our data with published sequences, three sequences obtained from raccoons and raccoon dogs shared the same haplotypes as those reported in humans, dogs, and cats in Japan. Conclusions Our findings show a high prevalence of T. callipaeda in raccoons, suggesting that this invasive carnivore species serves as an important natural reservoir of T. callipaeda in the Kanto region of Japan, an area with the highest human population of the country. Graphical Abstract
  • Toshihiro Tokiwa, Chiho Kezuka, Shoto Yamada, Shyun Chou, Shinichi Nakamura
    Parasitology International, 90(102614) 102614-102614, Oct, 2022  Peer-reviewedLead authorCorresponding author
  • Toshihiro Tokiwa, Shyun Chou, Hina Kitazoe, Keiko Ito, Ryouta Torimoto, Yuki Shoshi, Chizu Sanjoba, Masami Yamamoto, Hisashi Yoshimura
    International Journal for Parasitology: Parasites and Wildlife, 18 194-200, Aug, 2022  Peer-reviewedLead authorCorresponding author
  • Shyun Chou, Shinichiro Hadano, Atsushi Kojima, Mario Yorisaki, Masaru Yasuda, Kazunori Ike, Toshihiro Tokiwa
    Journal of Microbiology, Immunology and Infection, 55 527-534, Jun, 2022  Peer-reviewedLast author
  • Toshihiro Tokiwa, Shyun Chou, Riona Morizane, Natsuhiko Yoshikawa
    International Journal for Parasitology: Parasites and Wildlife, 17 194-198, Apr, 2022  Peer-reviewedLead authorCorresponding author
  • Shyun Chou, Masato Ozawa, Katsuki Matsubara, Kenichi Tamukai, Toshihiro Tokiwa
    Parasitology International, 87 102524, Apr, 2022  Peer-reviewedLast authorCorresponding author
  • Fuyumi Yumoto, Toshihiro Tokiwa, Shyun Chou, Michihiro Ueda
    The Journal of Veterinary Medical Science, 83(11) 1760-1763, Nov, 2021  Peer-reviewedLead authorCorresponding author
  • Toshihiro Tokiwa, Shyun Chou, Yuki Tochigi, Kentaro Katayama, Donald W. Duszynski
    International Journal for Parasitology: Parasites and Wildlife, 15 199-207, Aug, 2021  Peer-reviewedLead authorCorresponding author
  • Rie Maruko, Toshihiro Tokiwa, Junji Nakai, Shin-ichi Nakamura
    Parasitology International, 102349, Aug, 2021  Peer-reviewedLead authorCorresponding author
  • Shyn Chou, Nobumoto Izawa, Kazunori Ike, Toshihiro Tokiwa*
    International Journal for Parasitology: Parasites and Wildlife, 14 75-83, Apr, 2021  Peer-reviewedLast authorCorresponding author
  • Fumiya Urushiyama, Katsuki Matsubara, Kandai Doi, Masakatsu Taira, Tomoyoshi Komiya, Toshihiro Tokiwa
    Parasitology International, 78 102157-102157, Oct, 2020  Peer-reviewedLast authorCorresponding author
    On December 11, 2018, a single unengorged adult tick was found on the body surface of the trunk of an imported wild-caught Linnaeus's two-toed sloth (Choloepus didactylus) during a routine health check in an animal clinic in Tokyo, Japan. The tick was identified as Amblyomma geayi based on the morphological and molecular characteristics. This is the first case of the introduction of an Amblyomma species to Japan via an imported pet sloth. The present study highlights the current loopholes in Japan's regulatory system for animal imports.
  • Shyun Chou, Toshihiro Tokiwa, Shinichiro Hadano, Nobumoto Izawa, Michihiro Ueda, Atsushi Kojima, Kazunori Ike
    Parasitology International, 77 102101, Aug, 2020  Peer-reviewedCorresponding author
  • Toshihiro Tokiwa, Hisashi Yoshimura, Keiko Ito, Shyun Chou, Masami Yamamoto
    76 102058, Jun, 2020  Peer-reviewedLead authorCorresponding author
  • Rie Kubota, Toshihiro Tokiwa, Katsuki Matsubara, Minoru Okamoto, Kazunori Ike
    International Journal for Parasitology: Parasites and Wildlife, 11 83-87, Apr, 2020  Peer-reviewedLead authorCorresponding author
    Uromastyx is a genus of the herbivorous agamid lizards, also known as spiny-tailed lizards or mastigures, which are found in parts of Africa and the Middle East. Currently, several species of this genus are available in the international pet trade in Japan. In this study, two imported wild-caught spiny-tailed lizards (Arabian blue mastigure, Uromastyx ornata philbyi, and Sudan mastigure, Uromastyx dispar flavifasciata) were diagnosed with a Cryptosporidium (Apicomplexa: Cryptosporidiidae) infection based on the presence of the oocysts in the rectal feces using sucrose flotation and light microscopy examination at a local animal hospital in Tokyo, Japan. One of the lizards had died, and histopathological examination revealed enteritis with the Cryptosporidium parasite. Sequence analyses using the small subunit ribosomal RNA, actin, and 70-kDa heat shock protein genes indicated that the lizards had contracted a novel variant of C. avium that commonly infects avian species.
  • Takuji Tanaka, Toshihiro Tokiwa, Hideo Hasegawa, Teruki Kadosaka, Makoto Itoh, Fumiaki Nagaoka, Haruhiko Maruyama, Yuki Mizuno, Naoki Shirai
    2 468-471, Mar, 2020  Peer-reviewed
  • Jian Xu, Rikito Hiramatsu, Hamizah Suhaimi, Tatsuya Kato, Akari Fujimoto, Toshihiro Tokiwa, Kazunori Ike, Enoch Y. Park
    Vaccine, 37 6426-6434, Oct, 2019  Peer-reviewed
  • Toshihiro Tokiwa, Hisashi Yoshimura, Sayoko Hiruma, Yukie Akahori, Ayami Suzuki, Keiko Ito, Masami Yamamoto, Kazunori Ike
    International Journal for Parasitology: Parasites and Wildlife, 9 244-247, Aug, 2019  Peer-reviewedLead authorCorresponding author
  • Rie Kubota, Matsubara Katsuki, Kenichi Tamukai, Kazunori Ike, Toshihiro Tokiwa
    Parasitology International, 68(1) 9-13, Feb, 2019  Peer-reviewedCorresponding author
    Long-tailed chinchillas Chinchilla lanigera are popular rodent species kept both in households, where they are hand-raised as pets, and in zoological facilities. From January 2016 to February 2017, 13 juvenile chinchillas from five facilities in Japan were diagnosed with cryptosporidiosis at the animal hospital. Eight of the cases were fatal. All of the animals were imported from the Czech Republic by the same vendor. Histopathological and multilocus sequence analyses using 18S ribosomal RNA, actin, 70-kDa heat shock protein, and 60-kDa glycoprotein genes confirmed Cryptosporidium ubiquitum of subtype XIId as the etiological agent. Multilocus analysis demonstrated the presence of two new sequence types closely related to the C. ubiquitum Xlld strain isolated from a human in the USA. This study indicated that potentially zoonotic Cryptosporidium is widespread and may have caused a high number of deaths among imported juvenile chinchillas.
  • Toshihiro Tokiwa*, Ai Ohnuki, Rie Kubota, Kenichi Tamukai, Kazunori Ike
    International Journal for Parasitology: Parasites and Wildlife, 7(3) 268-273, Dec, 2018  Peer-reviewedLead authorCorresponding author
    In this study, we provide the first description of Cystoisospora infection in Asian small-clawed otters (Aonyx cinereus). In July 2017, three juvenile otters recently imported from the Republic of Indonesia showed severe diarrhea and were diagnosed with coccidial infection; two of them eventually died. Fecal examination revealed the presence of numerous oocysts. Sporulated oocysts showed typical Cystoisospora features, measuring 24.6 ± 1.6 (22.0-27.0) × 21.8 ± 1.4 (19.0-25.0) μm, with an oocyst length/width ratio of 1.1 ± 0.1 (1.0-1.3). Each sporocyst contained four sporozoites in a head-to-tail arrangement. The Stieda body was absent, and the sporocyst residuum was present. These morphological characteristics differentiated this species from the other valid Cystoisospora species described from mustelids. Molecular analysis was conducted at two loci: the nuclear 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I genes. The 18S sequence showed high similarity with canine Cystoisispora ohioensis (1-bp difference, 1422/1423 [99.9%]). At the cytochrome c oxidase subunit I gene locus, the sequence from otters was identical to that of feline Cystoisospora rivolta (847/847 [100%]). Phylogenetic analyses using concatenated data demonstrated that Cystoisospora sp. from otters and C. rivolta grouped together in the same Cystoisospora clade. Based on these data, we concluded that Cystoisospora sp. detected from otters appeared to be highly similar to C. rivolta.
  • Akira Ito, Winnie Eckardt, Tara S. Stoinski, Thomas R. Gillespie, Toshihiro Tokiwa
    European Journal of Protistology, 65 42-56, May, 2018  Peer-reviewedLast author
  • Kensuke Taira, Shohei Nakamura, Toshihiro Tokiwa, Yumi Une
    Journal of Parasitology, 104 424-428, Apr, 2018  Peer-reviewed
  • Akira Ito, Toshihiro Tokiwa
    European Journal of Protistology, 62 1-10, Feb 1, 2018  Peer-reviewedLast author
    We described the infraciliature of Opisthotrichum janus, Epidinium ecaudatum, and Ophryoscolex purkynjei, belonging to the family Ophryoscolecidae, from pyridinated silver carbonate impregnated specimens. The adoral polybrachykinety is C-shaped in Opi. janus, whereas it is spiral-shaped in Epi. ecaudatum and Oph. purkynjei. The vestibular polybrachykinety is slender and short in Opi. janus, whereas slender and long in Epi. ecaudatum and Oph. purkynjei. The paralabial kineties are composed of several short kineties along the adoral polybrachykinety. The dorsal polybrachykinety is displaced posteriorly. This study provides information on the diagnostic features of the subfamily Ophryoscolecinae to which Opi. janus, Epi. ecaudatum, and Oph. purkynjei belong. A C-shaped or spiral-shaped adoral polybrachykinety and slender vestibular polybrachykinety are the diagnostic features of the subfamily Ophryoscolecinae in addition to their general features of a cylindrical body, tubular vestibulum, dorsal ciliary zone considerably displaced posteriorly, well developed skeletal plates, and macronucleus beneath the right body surface. Opi. janus, Epi. ecaudatum, and Oph. purkynjei show the basic form of morphogenesis of the ciliature, similar to that in the subfamily Diplodiniinae, with four primordia developing into the oral and dorsal ciliature.
  • Toshihiro Tokiwa, Yuya Kobayashi, Kazunori Ike, Yasuyuki Morishima, Hiromu Sugiyama
    Japanese Journal of Infectious Diseases, 71(1) 88-89, 2018  Peer-reviewed
  • Mizuki Yamamoto, Toshihiro Tokiwa, Miki Tobiume, Shigeru Akamatsu, Kayoko Matsuo, Junji Moribe, Kazunori Ike
    International Journal for Parasitology: Parasites and Wildlife, 6(3) 354-360, Dec 1, 2017  Peer-reviewedLead authorCorresponding author
    Hepatozoon apri n. sp. is described from Japanese wild boars Sus scrofa leucomystax in Japan. The gamonts in the peripheral blood leukocytes were 11.6 ± 1.4 × 6.7 ± 1.3 μm in size. The meronts in the muscle tissues were 35.0–47.5 μm in length and 26.5–30 μm in width. A high rate (53.0%) of infection was found by nested PCR using muscle specimens from 181 wild boars captured in Tokushima, Japan. A phylogenetic analysis based on 18S rRNA gene sequences revealed that H. apri n. sp. detected in wild boars is closely related to Hepatozoon spp. isolated from carnivores. This is the first description of a species belonging to the genus Hepatozoon detected in ungulates.
  • Akira Ito, Winnie Eckardt, Tara S. Stoinski, Thomas R. Gillespie, Toshihiro Tokiwa
    European Journal of Protistology, 60 68-75, Aug, 2017  Peer-reviewedLast author
    A new entodiniomorphid ciliate species, Gorilloflasca africana n.g., n. sp. was described from the Virunga mountain gorillas, Gorilla beringei beringei, in Rwanda. It is characterized by a flask-shaped body, a long tubular vestibulum, a round frontal lobe, a large posterior cavity, an ellipsoidal or peanut-shaped macronucleus and a single contractile vacuole. G. africana has the adoral and the vestibular ciliary zones in the buccal area. The adoral ciliary zone is non-retractable, encircling the vestibular opening. The vestibular ciliary zone extends posteriorly in the vestibulum. The somatic ciliary zones are the cavity ciliary zone in the posterior cavity along the ventral side of its opening and two longitudinal ciliary zones on the dorsal body surface. The buccal infraciliary bands of G. africana are a C-shaped adoral polybrachykinety, a stick-shaped vestibular kinety band, and paralabial kineties. The anterior region of the vestibular kinety band is composed of short kineties whereas, kineties in the remaining region are longitudinal. The somatic infraciliary bands are a cavity polybrachykinety and two longitudinal polybrachykineties. Gorilloflasca is a member of the family Blepharocorythidae based on the non-retractable adoral ciliary zone, the frontal lobe, the large posterior cavity and the vestibular longitudinal kineties. (C) 2017 Elsevier GmbH. All rights reserved.
  • Toshihiro Tokiwa, Atsushi Kojima, Shun Sasaki, Rie Kubota, Kazunori Ike
    Parasitology International, 66(2) 100-105, Apr, 2017  Peer-reviewedLead authorCorresponding author
    Five individuals of the domestic Java sparrows, Lonchura oryzivora (Ayes: Estrildidae), were examined for coccidian parasites. Sporulated oocysts had two sporocysts containing four sporozoites each. Sporulated oocysts (n = 30) were spherical, with a two splinter-like polar granules. Oocyst size was 22.1 x 20.7 (20.0-25.0 x 20.0-22.5) mu m. They had a thick wall that consisted of a pale yellow outer layer and a dark yellow inner layer, and lacked micropyle and residuum. Sporocysts (n = 60) were elongated ovoid 14.1 x 9.8 (12.5-15.0 x 7.5-10.0) mu m, smooth walled, and colorless, with crescent-shaped Stieda and indistinct substieda bodies. Sporocyst residuum was interspersed between sporozoites. Sporozoites were oriented transverse to the sporocyst longitudinal axis. On the basis of morphological data, the species isolated in the present study is a new species of Isospora and propose the name Isospora lunaris n. sp. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Kojiro Shibasaki, Toshihiro Tokiwa, Akihiro Sukegawa, Hirotaka Kondo, Kenichi Tamukai, Yumiko Haga, Kazunori Ike
    JMM Case Reports, 4 1-5, Feb, 2017  Peer-reviewedLead authorCorresponding author
  • Emi Sasaki, Toshihiro Tokiwa, Kosuke Tsugo, Yukiko Higashi, Hiroshi Hori, Yumi Une
    Journal of Comparative Pathology, 156(2-3) 281-285, Feb, 2017  Peer-reviewedLead author
    We describe the development of neurological signs in four juvenile black-and-white ruffed lemurs (Varecia variegate), housed at a petting zoo in Japan. The clinical course was severe, with three lemurs dying within 1 day of the appearance of clinical signs. The other lemur was treated and survived. Pathological analyses demonstrated meningitis and the presence of gram-negative bacilli in the cerebrum, cerebellum, palatine tonsil and liver. Klebsiella pneumoniae was isolated from the brain of all of the dead lemurs. Multilocus sequence typing analysis showed that all the isolates were sequence type 86 (ST86). To our knowledge, this is the first determination of K. pneumoniae infection in ruffed lemurs of this genus. K. pneumoniae infection may represent a risk to lemurs and people who come into contact with infected animals. (C) 2017 Elsevier Ltd. All rights reserved.
  • Akira Ito, Winnie Eckardt, Tara S. Stoinski, Thomas R. Gillespie, Toshihiro Tokiwa
    European Journal of Protistology, 54 47-58, Jun, 2016  Peer-reviewedLast author
    The morphology of Prototapirella fosseyi n. sp., P. rwanda n. sp. and P. gorillae Imai, Ikeda, Collet, and Bonhomme, 1991 in the Entodiniomorphida were described from the mountain gorillas, Gorilla beringei beringei, in Rwanda. The ciliates have a retractable adoral ciliary zone, four non-retractable ciliary tufts in four caudalia, and one broad skeletal plate beneath the body surface. P. rwanda has a dorsal lobe and ventral lobes in two rows whereas P. fosseyi has no lobes. These two new species have an elongated body, a flat tail flap leaning to the ventral, a macronucleus with a tapering anterior end, a round posterior end and a shallow depression on the dorsal side, a micronucleus lying near the anterior end of macronucleus, a thin left region of the skeletal plate, a distinct skeletal rod plate, and four contractile vacuoles. P. gorillae has some variations in the nuclei and the skeletal plate. The infraciliary bands of three Prototapirella species were the same as some Triplumaria species; a C-shaped adoral polybrachykinety, a slender perivestibular polybrachykinety, and paralabial kineties in their retractable adoral ciliary zone and short lateral polybrachykineties in their four caudalia. The perivestibular polybrachykinety is joined only to the right end of adoral polybrachykinety. (C) 2016 Elsevier GmbH. All rights reserved.
  • Toshihiro Tokiwa, Hiromu Sugiyama, Kensuke Taira, Yasuhiro Yoshikawa, Yumi Une
    Journal of Parasitology, 102(2) 293-294, Apr, 2016  Peer-reviewedLead author
    Baylisascaris potosis causes larva migrans in animals. The present study evaluated the prevalence of B. potosis in captive kinkajous (Potos flavus) and the ability of milbemycin to treat natural infections of B. potosis in 2 female wild-caught kinkajous. In 2012, fecal samples were collected from 16 kinkajous in 6 zoological gardens and 29 imported captive kinkajous from 4 pet traders in Japan. Although all samples from zoological gardens were negative, 8 kinkajous from traders were positive for Baylisascaris eggs, at least 4 of which were wild caught in the Republic of Guyana. No associated human illness was reported from any of the facilities. The 2 infected kinkajous received a single oral administration of Milbemycin (R) A Tablets, which delivers 0.69-0.89 mg/kg milbemycin oxime. Fecal examinations on days 14 and 30 were negative for Baylisascaris eggs. These results demonstrated that milbemycin oxime has possible anthelmintic efficacy against Baylisascaris roundworms in captive kinkajous. We conclude that Baylisascaris infections are highly prevalent in wild-caught kinkajous in Japan and that most of the infected kinkajous were imported from the Republic of Guyana.
  • Kenichi Tamukai, Toshihiro Tokiwa, Hideki Kobayashi, Yumi Une
    Veterinary Dermatology, 27(2) 99-E28, Apr, 2016  Peer-reviewed
    BackgroundVarious pathogens cause skin diseases in lizards. An outbreak of skin disease occurred in a population of 100 inland bearded dragons at a breeding facility in Japan; 50 developed skin lesions and 15 mortalities were reported. Hypothesis/ObjectivesTo identify the pathogens responsible for the skin lesions and to determine the cause of death. AnimalsEight specimens (three dead, two euthanized, three living) were randomly selected from a group of inland bearded dragons with skin lesions consisting of multifocal superficial dermatitis. MethodsBiopsy samples were taken from skin lesions and healthy skin of the live specimens. Postmortem examinations were performed on the dead and euthanized specimens. Skin samples were processed for microbiological culture, 16S ribosomal DNA (rDNA) sequencing for bacteria, ranavirus major capsid protein (MCP) gene sequencing and histopathological examination. Histopathological examinations were also performed on postmortem tissue samples. ResultsBoth Austwickia chelonae and ranavirus (DNA) were detected in the skin lesions. Pathological examination revealed no significant visceral lesions caused by A. chelonae or ranavirus infection in dead specimens. Conclusions and clinical importanceTo the best of the authors' knowledge this is the first report of dermatophilosis due to A. chelonae infection in lizards and the first description of a concurrent infection with a ranavirus. The combined infection associated with the skin lesions may have been the primary cause of death. Co-infection with a ranavirus should be considered as a possible factor in cases of reptilian dermatophilosis. Resume ContexteDes pathogenes varies sont responsables des dermatoses des lezards. Un foyer de dermatose s'est produit dans une population de 100 agames barbus d'elevage au Japon; 50 ont developpe des lesions cutanees et 15 morts ont ete rapportes. Hypotheses/ObjectifsIdentifier les pathogenes responsables des lesions cutanees et determiner la cause de la mort. SujetsHuit cas (trois morts et deux euthanasies, trois vivants) ont ete choisis au hasard d'un groupe d'agames barbus ayant des lesions consistants en une dermatite superficielle multifocale. MethodesDes echantillons de biopsies ont ete preleves des lesions cutanees et de la peau saine des cas vivants. Des examens post-mortem ont ete realises sur les cas euthanasies et morts. Des echantillons cutanes ont ete preleves pour culture microbiologique, sequencage d'ADN ribosomal 16S (rDNA) pour des bacteries, sequencage genetique de MCP (major capsid protein) de ranavirus et examens histopathologiques. Les examens histopathologiques etaient egalement realises sur des echantillons de tissus post mortem. ResultatsA la fois Austwickia chelonae et ranavirus (DNA) ont ete detectes dans les prelevements cutanes. L'examen pathologique n'a pas permis de mettre en evidence de lesions viscerales causees par une infection a A. chelonae ou ranavirus dans les cas morts. Conclusions et importance cliniqueA la connaissance des auteurs, ceci est le premier cas de dermatophilose due a A. chelonae chez les lezards et la premiere description d'une infection concomitante avec un ranavirus. L'infection combinee associee aux lesions cutanees pourrait etre la cause primaire de la mort. Une co-infection a ranavirus devrait etre consideree comme un facteur possible de dermatophilose reptilienne. Resumen Introduccionvarios patogenos causan enfermedades de la piel en lagartos. Se produjo una epizootia de enfermedad de la piel en una poblacion de unos 100 dragones barbudos en unas instalaciones de cria en cautividad de Japon; 50 desarrollaron lesiones de la piel y se produjeron 15 muertes. Hipotesis/Objetivosidentificar patogenos responsables de las lesiones de la piel y determinar la causa de mortalidad. Animalesocho especimenes (tres muertos, dos eutanasiados, y tres vivos (fueron seleccionados de forma aleatoria de un grupo de dragones barbudos con lesiones de la piel que consistieron en dermatitis superficial multifocal. Metodosse tomaron muestras de biopsia de lesiones de la piel y la piel sana de los animales vivos. Se realizo un examen postmortem en los animales muertos y eutanasiados. Las muestras de piel se procesaron para cultivo microbiologico, secuenciacion del DNA 16S ribosomal (rRNA), secuenciacion genica de la proteina mayor de la capside de ranavirus (MCP) y examen histopatologico. Tambien se desarrollo examen histopatologico de las muestras postmortem de otros tejidos Resultadosse detectaron Austwickia chelonae y ranavirus (DNA) en las lesiones de la piel. El examen patologico revelo ausencia de lesiones viscerales significativas causadas por A. chelonae o ranavirus en los animales muertos. Conclusion e importancia clinicaa nuestro entender esta es la primera descripcion de dermatofilosis causada por infeccion con A. chelonae en lagartos y la primera descripcion de infeccion concurrente con ranavirus. La infeccion combinada produciendo lesiones de la piel puede haber sido la causa primaria de mortalidad. La co-infeccion con ranavirus debe considerarse como un factor importante en casos de dermatofilosis en reptiles. Zusammenfassung HintergrundVerschiedene Pathogene verursachen Hauterkrankungen bei Echsen. In einer Zuchtungseinrichtung in Japan brach eine Hautkrankheit bei einer Population von 100 Binnenbartagamen aus; 50 Tiere entwickelten Hautveranderungen und 15 Tiere starben. Hypothese/ZieleEine Identifizierung der Pathogene, die fur die Hautveranderungen verantwortlich waren und eine Feststellung der Todesursache. TiereAcht Exemplare (drei tote, zwei euthanasierte, drei lebende) wurden zufallig aus einer Gruppe von Binnenbartagamen, die Hautveranderungen aufwiesen, die einer multifokalen oberflachlichen Dermatitis entsprachen, ausgewahlt. MethodenEs wurden Biopsien von Hautveranderungen und von gesunder Haut der lebenden Exemplare genommen. Es wurden post mortem Untersuchungen an den toten und euthanasierten Exemplaren durchgefuhrt. Aus den Hautproben wurden mikrobielle Kulturen angelegt, sowie 16S ribosomale DNA (rDNA) Sequenzierung fur Bakterien, Ranavirus Major Capsid Protein (MCP) Gensequenzierung und eine histopathologische Untersuchung durchgefuhrt. Histopathologische Untersuchungen wurden ebenfalls an post mortem Gewebe durchgefuhrt. ErgebnisseSowohl Austwickia chelonae als auch Ranavirus (DNA) wurden in den Hautveranderungen gefunden. Bei der pathologischen Untersuchung der toten Exemplare wurden keine signifikanten viszeralen Veranderungen durch A. chelonae oder Ranavirus festgestellt. Schlussfolgerungen und klinische BedeutungNach bestem Wissen der Autoren handelt es sich hierbei um den ersten Bericht einer Dermatophilose aufgrund einer A. chelonae Infektion bei Echsen und um die erste Beschreibung einer gleichzeitigen Ranavirus Infektion. Die kombinierte Infektion, zusammen mit den Hautveranderungen, konnte die Primarursache fur den Tod der Tiere gewesen sein. Eine Co-Infektion mit Ranavirus sollte als moglicher Faktor bei Fallen von Dermatophilose bei Reptilien bedacht werden.
  • Hisashi Yoshimura, Yoko Matsuda, Masami Yamamoto, Tomohiko Endo, Hiroshi Kajigaya, Toshihiro Tokiwa, Toshiyuki Ishiwata, Shinji Kamiya
    Journal of Nippon Medical School, 82(6) 264-265, Dec, 2015  Peer-reviewed
  • Toshihiro Tokiwa, Sho Kadekaru, Masao Ito, Makoto Yoshida, Yumi Une
    Diseases of Aquatic Organisms, 116(3) 199-203, Oct, 2015  Peer-reviewedLead author
    In February 2014, wild American bullfrog Lithobates catesbeianus tadpoles from an artificial pond in the Kyusyu region, Japan, presented with coelomic and subcutaneous edema and erythema within the skin. A pathological examination of 57 tadpoles of American bullfrogs in the region was conducted to evaluate the disease. Crystal deposition of varying degrees was found in the kidneys of 35 tadpoles (61.4%). The crystals were transparent, pleomorphic in shape, highly birefringent in polarized light, and arranged in a radial pattern within the renal tubular lumen. Using Alizarin Red S stain and liquid chromatography, these crystals were identified as calcium oxalate. Severe coelomic and subcutaneous edema was observed in 7 of these 35 tadpoles (20.0%). Ammonia levels in coelomic fluid were extremely elevated (> 1000 mu g dl(-1)) in 4 tadpoles examined. These findings suggest that oxalate deposition in kidneys causes metabolic disorder with renal nephropathy. The source of the oxalate could not be determined; however, the presence of calcium oxalates in pond sediments, as revealed by liquid chromatography, suggested that the deposition was most likely due to ingestion of oxalate materials from the environment. This is the first report of oxalate nephropathy in free-living amphibians.
  • Toshihiro Tokiwa, Kosuke Tsugo, Shohei Nakamura, Kensuke Taira, Yumi Une
    Parasitology International, 64(5) 284-287, Oct, 2015  Peer-reviewedLead author
    Roundworms of the genus Baylisascaris are natural parasites primarily of wild carnivores, and they can occasionally cause infection in humans and animals. Infection results in visceral larva migrans and/or neural larva migrans, which can be severe or fatal in some animals. Recently, Baylisascaris nematodes isolated from kinkajous (Potos flavus) and previously referred to as Baylisascaris procyonis were renamed as Baylisascaris potosis; however, data regarding the pathogenicity of B. potosis towards animals and humans are lacking. In the present study, we experimentally infected squirrel monkeys (Saimiri sciureus) with B. potosis to determine the suitability of the monkey as a primate model. We used embryonated eggs of B. potosis at two different doses (10,000 eggs and 100,000 eggs) and examined the animals at 30 days post-infection. Histopathological examination showed the presence of B. potosis larvae and infiltration of inflammatory cells around a central B. potosis larvae in the brain, intestines, and liver. Nevertheless, the monkeys showed no clinical signs associated with infection. Parasitological examination revealed the presence of B. potosis larvae in the intestines, liver, lung, muscles, brain, kidney, and diaphragm. Our findings extend the range of species that are susceptible to B. potosis and provide evidence for the zoonotic potential of larva migrans in high dose infections. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
  • Toshihiro Tokiwa, Kensuke Taira, Yumi Une
    Journal of Parasitology, 101(1) 114-115, Feb, 2015  Peer-reviewedLead author
    The present study evaluated the pathogenicity of Baylisascaris potosis, a newly described ascarid nematode, in Mongolian gerbils. Gerbils were infected with varying doses of either B. potosis or Baylisascaris transfuga embryonated eggs (100, 1,000, and 4,000) for 30 days postinfection (pi). Baylisascaris potosis-infected gerbils showed no clinical signs of disease; however, gerbils exposed to 1,000 and 4,000 B. transfuga eggs showed severe neurologic signs at 22-29 days and 14-15 days pi, respectively. Histopathologic examination revealed larvae and lesions in the intestine, lung, liver, and muscles of B. potosis-infected gerbils, but not in the brain, whereas B. transfuga larvae were found only in the brain and muscle. These results indicate that B. potosis larvae migrate through numerous organs and are associated with visceral larva migrans in gerbils, but less frequently migrate to the nervous system in gerbils than does B. transfuga.
  • Toshihiro Tokiwa, Kensuke Taira, Mutsumi Yamazaki, Akane Kashimura, Yumi Une
    Parasitology International, 63(5) 705-707, Oct, 2014  Peer-reviewedLead author
    This report describes a case of peritoneal larval cestodiasis caused by tetrathyridia of IVIesocestoides sp. in an adult female squirrel monkey. The monkey had lived in a zoological garden in Japan and had a clinical history of wasting. At necropsy, numerous whitish oval masses were found in the liver and peritoneal cavity. These masses contained larval cestodes. Morphological observation and molecular analyses of the mitochondrial 125 ribosomal RNA gene and cytochrome c oxidase subunit 1 gene sequences allowed us to identify the larva as the tetrathyridium of Mesocestoides sp. This is the first report of Mesocestoides larvae in a squirrel monkey in Japan. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
  • Shoichi Fuma, Yumi Une, Sadao Ihara, Kumi Matsui, Tomoo Kudo, Toshihiro Tokiwa, Yoshihisa Kubota, Haruhi Soeda, Takahiro Ishikawa, Kazutaka Doi, Yoshito Watanabe, Satoshi Yoshida
    Journal of Environmental Radioactivity, 135 84-92, Sep, 2014  Peer-reviewed
    The Tohoku hynobiid salamanders, Hynobius lichenatus, were chronically irradiated with gamma-rays from embryonic to juvenile stages for 450 days. At 490 mu Gy h(-1) or lower dose rates, growth and survival were not significantly affected by irradiation, and any morphological aberrations and histological damages were not observed. At 4600 mu Gy h(-1), growth was severely inhibited, and all the individuals died mostly at the juvenile stage. Chronic LD50 was 42 Gy as a total dose. In the liver, the number of hematopoietic cells was significantly reduced in the living juveniles, and these cells disappeared in the dead juveniles. In the spleen, mature lymphocytes were depleted in the living larvae, and almost all the heamtopoietic cells disappeared in the dead juveniles. These results suggest that this salamander died due to acute radiation syndrome, i.e., hematopoietic damage and subsequent sepsis caused by immune depression. The death would be also attributed to skin damage inducing infection. At 18,000 mu Gy h(-1), morphological aberrations and severe growth inhibition were observed. All the individuals died at the larval stage due to a multiple organ failure. Chronic LD50 was 28 Gy as a total dose. Assuming that chronic LD50 was 42 Gy at lower dose rates than 4600 mu Gy h(-1), a chronic median lethal dose rate could be estimated to be <340 mu Gy h(-1) for the whole life (>14 years). These results suggest that, among guidance dose rates, i.e., 4 -400 mu Gy h(-1), proposed by various organisations and research programmes for protection of amphibians and taxonomic groups or ecosystems including amphibians, most of them would protect this salamander but the highest value may not on the whole life scale. (C) 2014 Elsevier Ltd. All rights reserved.
  • Toshihiro Tokiwa, Shohei Nakamura, Kensuke Taira, Yumi Une
    Parasitology International, 63(4) 591-596, Aug, 2014  Peer-reviewedLead author
    We describe a new nematode species, Baylisascaris potosis n. sp., isolated from captive kinkajou, Potos flavus, from the Cooperative Republic of Guyana. The nematode was found in fecal specimens, identified morphologically, and confirmed genetically. The new species is similar to Baylisascaris procyonis, Baylisascaris columnar's, and other Baylisascaris species, but is distinguished by the position of the male phasmidial pole. Nuclear and mitochondrial DNA sequence analyses confirmed that the new species is phylogenetically distinct from all the members of the genus Baylisascaris, and groups with B. procyonis and B. columnar's. This nematode is the 10th species assigned to the genus Baylisascaris. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
  • Toshihiro Tokiwa, Wataru Ueda, Satoshi Takatsuka, Kiyotaka Okawa, Masayuki Onodera, Nobuo Ohta, Nobuaki Akao
    Parasitology International, 63(1) 143-147, Feb, 2014  Peer-reviewedLead author
    We describe a nematode larva in a subcutaneous nodule excised from a 44-year-old Chinese male who had been living in Japan for 15 years. Morphological features suggested that the worm was a dioctophimatid nematode. PCR amplification and sequencing of small subunit ribosomal DNA and mitochondrial cytochrome subunit c oxidase genes allowed us to identify the larva as the giant kidney worm, Dioctophyme renale (Goeze, 1972). This is the first molecularly confirmed human case of a dermal D. renale infection. (C) 2013 Elsevier Ireland Ltd. All rights reserved.
  • Toshio Arai, Nobuaki Akao, Takenori Seki, Takashi Kumagai, Hirofumi Ishikawa, Nobuo Ohta, Nobuto Hirata, So Nakaji, Kenji Yamauchi, Mitsuru Hirai, Toshiyasu Shiratori, Masayoshi Kobayashi, Hiroyuki Fujii, Eiji Ishii, Mikio Naito, Shin-ichi Saitoh, Toshikazu Yamaguchi, Nobumitsu Shibata, Masamune Shimo, Toshihiro Tokiwa
    PLOS ONE, 9(2) e89188, Feb, 2014  Peer-reviewed
    Background: Anisakiasis is a parasitic disease caused primarily by Anisakis spp. larvae in Asia and in Western countries. The aim of this study was to investigate the genotype of Anisakis larvae endoscopically removed from Middle Eastern Japanese patients and to determine whether mucosal atrophy affects the risk of penetration in gastric anisakiasis. Methods: In this study, 57 larvae collected from 44 patients with anisakiasis (42 gastric and 2 colonic anisakiasis) were analyzed retrospectively. Genotyping was confirmed by restriction fragment length polymorphism (RFLP) analysis of ITS regions and by sequencing the mitochondrial small subunit (SSU) region. In the cases of gastric anisakiasis, correlation analyses were conducted between the frequency of larval penetration in normal/atrophic area and the manifestation of clinical symptoms. Results: Nearly all larvae were A. simplex seusu stricto (s.s.) (99%), and one larva displayed a hybrid genotype. The A. simplex larvae penetrated normal mucosa more frequently than atrophic area (p = 0.005). Finally, patients with normal mucosa infection were more likely to exhibit clinical symptoms than those with atrophic mucosa infection (odds ratio, 6.96; 95% confidence interval, 1.52-31.8). Conclusions: In Japan, A. simplex s.s. is the main etiological agent of human anisakiasis and tends to penetrate normal gastric mucosa. Careful endoscopic examination of normal gastric mucosa, particularly in the greater curvature of the stomach will improve the detection of Anisakis larvae.
  • Toshihiro Tokiwa, Takuma Hashimoto, Tatsuo Yabe, Noriyuki Komatsu, Nobuaki Akao, Nobuo Ohta
    PLOS ONE, 8(8) e70729, Aug, 2013  Peer-reviewedLead author
    Background: Angiostrongylus cantonensis (Chen, 1935) is a parasite of murid rodents and causative agent of human neuro-angiostrongyliasis. In 2011, the Ogasawara Islands in the western North Pacific were assigned a World Natural Heritage site status. The occurrence of A. cantonensis is well documented in the Chichijima, Hahajima, and Anijima Islands. However, the occurrence of A. cantonensis in the other islands of the Ogasawara Islands has not been reported. Methodology/Principal Findings: Between March 2010 and July 2011, 57 Rattus norvegicus and 79 R. rattus were collected from 9 islands (the Hahajima group: Anejima, Imoutojima, Meijima, Mukohjima, and Hirajima; Chichijima group: Minamijima; Mukojima group: Nakoudojima and Yomejima; and Iwojima group: Iwojima). Adult nematodes were found in the pulmonary artery of 46 R. norvegicus collected in the 5 islands of the Hahajima group (Anejima, Meijima, Imoutojima, Hrajima, and Mukohjima Islands). These nematodes were identified by molecular analysis as A. cantonensis. Comparison of the mitochondrial DNA sequences confirmed that all the samples from the Ogasawara Islands shared only a single lineage of A. cantonensis, which has been previously detected in the Okinawa, Hawaii, and Brazil. Conclusions/Significance: We describe new endemic foci of rat angiostrongyliasis in the Hahajima group (Anejima, Meijima, Imoutojima, Hirajima, and Mukohjima Islands) of the Ogasawara Islands. These findings indicate that the endemic foci of A. cantonensis are widely distributed in the Ogasawara Islands. Although human cases have not yet been reported in the Ogasawara Islands, the widespread detection of A. cantonensis could be of importance from the perspective of public health.
  • Toshihiro Tokiwa, Tsunehito Harunari, Tsutomu Tanikawa, Noriyuki Komatsu, Nobuo Koizumi, Kwong-Chung Tung, Jun Suzuki, Teruki Kadosaka, Nobuhiro Takada, Takashi Kumagai, Nobuaki Akao, Nobuo Ohta
    Parasitology International, 61(3) 431-436, Sep, 2012  Peer-reviewedLead author
    We conducted a pilot survey of genetic variation of A. cantonensis using small subunit (SSU) ribosomal (r) RNA and mitochondrial cytochrome c oxidase subunit I (cox!) gene sequences. Two distinct SSU genotypes (Cl and G2) were identified among 17 individual A. cantonensis worms from 17 different geographical localities in Japan, Mainland China, Taiwan, and Thailand. The partial coxl sequences were determined for 83 worms from 18 different geographical localities from Japan, Mainland China, Taiwan, and Thailand. Phylogenetic analysis showed eight distinct coxl haplotypes (ad to ac8). In 16 out of 18 localities, only a single coxl haplotype was found. However, in two localities, two coxl haplotypes coexisted. The common haplotypes found were: haplotype ad l (Tokyo, Chiba, Kanagawa, Amamioshima Island, and Taichung), haplotype ac2 (Ishikawa, Shenzhen, and Lianjiang), haplotype ac5 (the Okinawa and the Ogasawara Islands), and haplotype ac7 (Miyagi, Aichi, and Kanagawa). Each of these regions is separated from the others by high mountain ranges or oceans. In addition, the lower genetic variation and particular geographical distribution of A. cantonensis in each location could indicate a founder effect, which may have resulted from multiple independent origins, and suggests that haplotypes migrated from endemic areas via human-related transportation. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
  • Nobuo Koizumi, Chie Nakajima, Tsunehito Harunari, Tsutomu Tanikawa, Toshihiro Tokiwa, Eriko Uchimura, Tokujiro Furuya, Claro Niegos Mingala, Marvin Ardeza Villanueva, Makoto Ohnishi, Yasuhiko Suzuki
    Journal of clinical microbiology, 50(6) 2072-2074, Jun, 2012  Peer-reviewed
    We developed a new loop-mediated isothermal amplification (LAMP) method to detect rrs, a 16S rRNA gene of pathogenic Leptospira spp. in urine. The method enables detection of two leptospiral cells per reaction mixture following boiling of urine specimens. The sensitivity of this method is higher than that of culture or of flaB nested PCR.
  • Toshihiro Tokiwa, Tsunehito Harunari, Tsutornu Tanikawa, Nobuaki Akao, Nobuo Ohta
    Parasitology International, 60(3) 324-326, Sep, 2011  Peer-reviewedLead authorCorresponding author
    We collected 24 brown rats, Rattus norvegicus. in Kanagawa Prefecture in Japan and found one rat harboring a dioctophymatid nematode. A single male and a female worm were recovered from the abdominal cavity and were identified as Dioctophyme renale based on morphologic features and a BLAST DNA sequence analysis. We describe the morphological features of the adult worms and eggs from this extremely rare case of D. renale infection in a brown rat. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

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