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Hayashi Naoki

Faculty of Veterinary Medicine　Veterinary Medicine　Disease ControlAssistant Professor
International Institute for Zoonosis ControlAssistant Professor

Researcher basic information

■ Degree
  • Bachelor of Veterinary Medicine, Hokkaido University, Mar. 2020
  • Doctor of Veterinary Medicine, Hokkaido University, Mar. 2024
■ URL
researchmap URLホームページURL■ Various IDs
ORCID IDJ-Global ID■ Research Keywords and Fields
Research Keyword
  • Echinococcus multilocularis
  • Taenia solium
  • Parasite
  • Next Generation Sequencing
  • Mitochondrial genome
  • Bioinformatics
  • Phylogenetic analysis
Research Field
  • Life Science, Veterinary medical science
  • Life Science, Parasitology
■ Educational Organization

Career

■ Career
Career
  • Apr. 2024 - Present
    Division of Parasitology, Veterinary Research Unit, International Institute for Zoonosis Control, Hokkaido University
  • Apr. 2024 - Present
    Assistant Professor, Laboratory of Parasitology, Graduate School of Infectious Diseases, Hokkaido University
  • Apr. 2022 - Mar. 2024
    JSPS Research Fellowship for Young Scientists (DC2)
Educational Background
  • Apr. 2020 - Mar. 2024, Hokkaido University, Graduate School of Infectious Diseases
  • Apr. 2014 - Mar. 2020, Hokkaido University, School of Veterinary Medicine, 共同獣医学課程
  • Apr. 2011 - Mar. 2014, Osaka Prefectural Kishiwada High School

Research activity information

■ Awards
■ Papers
  • Protoscolex Maturation in Echinococcus multilocularis Is Controlled by Host Genetic Factors Independent of Initial Development
    Moe Kogawa; Keisuke Sato; Teppei Nakamura; Naoki Hayashi; Hirokazu Kouguchi; Ryo Nakao; Masahito Hidaka; Hiroyuki Matsuyama; Nariaki Nonaka; Osamu Ichii; Takashi Agui; Masami Morimatsu
    Parasite Immunology, 48, 2, Wiley, 16 Feb. 2026, [Peer-reviewed]
    Japanese, Scientific journal, ABSTRACT

    Alveolar echinococcosis, caused by Echinococcus multilocularis , poses a serious public health concern. This parasite requires rodents as intermediate hosts for protoscolex maturation in the liver and subsequent transmission to definitive hosts. We aimed to identify the host genetic factors controlling protoscolex development and maturation in congenic mice carrying susceptible DBA/2 genomic segments on a resistant C57BL/6N background. We assessed the hepatic protoscoleces and immune‐related gene expression levels 16 weeks post‐oral infection. All congenic strains developed protoscoleces; however, the number and proportion of mature forms decreased as C57BL/6N‐derived genomic contribution on chromosome 1 increased. Differences in DBA/2‐derived segments revealed two loci, E. multilocularis protoscolex maturation 1 ( Empmat1 ) and 2 ( Empmat2 ), as regulators of protoscolex maturation, but not early development, where immune involvement was limited. T‐box transcription factor 21 expression was correlated with protoscolex maturation; however, it lay outside Empmat1 and Empmat2 and was unlikely to be the responsible gene. Therefore, protoscolex maturation is potentially regulated by multiple host genetic factors distinct from those involved in early development, with B6‐derived alleles exerting inhibitory effects, possibly via non‐immune host mechanisms. Elucidation of these genetic pathways can reveal novel targets to disrupt the life cycle and reduce the zoonotic transmission of E. multilocularis .
  • Effectiveness of eprinomectin, albendazole and their combination therapy against strongyle nematode in dairy goats: A clinical field study using nemabiome-integrated approach in Thailand
    Thanakorn Rompo; Naoki Hayashi; Takaya Hoketsu; Ernest Teo; Nariaki Nonaka; Boondarika Namboopha; Tawatchai Singhla; Songphon Buddhasiri; Naoaki Misawa; Ryo Nakao; Saruda Tiwananthagorn
    Current Research in Parasitology & Vector-Borne Diseases, 100345, Elsevier BV, Jan. 2026, [Peer-reviewed]
    English, Scientific journal
  • Introduction and distributional expansion of Echinococcus multilocularis in Japan: a review from genetic perspectives
    Naoki Hayashi; Ryo Nakao; Nariaki Nonaka
    Japanese Journal of Veterinary Parasitology, 24, 1, 2, 1, 12, Japanese Society of Veterinary Parasitologists, 31 Dec. 2025, [Lead author, Corresponding author]
    Japanese, Scientific journal, 50789974;47267510;51158900;47041003

    Download
  • Rewilded horses as a nature-based solution for wintertime tick control in Japan: help or hindrance?
    Mackenzie L. Kwak; Hazuki Echigo; Takaya Hoketsu; Yurie Taya; Hideka Numata; Yuto Shiraki; Samuel Kelava; Greg Markowsky; Daniel McInnes; Naoki Hayashi; Nariaki Nonaka; Masahito Kawai; Ryo Nakao
    Experimental and Applied Acarology, 95, 4, Springer Science and Business Media LLC, 02 Dec. 2025, [Peer-reviewed]
    Japanese, Scientific journal
  • Ten simple rules for implementing deep amplicon sequencing in parasitology
    Jan Šlapeta; Jürgen Krücken; Alicia Rojas; Alex Chambers; Lynsey A. Melville; María Martínez-Valladares; Candela Canton; Emily K. Francis; Osama Zahid; Ana Cláudia A. Albuquerque; Dave J. Bartley; Cesar C. Bassetto; Orla Byrne; Vito Colella; Livio M. Costa-Junior; Stephen R. Doyle; Mike Evans; Abdul Ghafar; Pablo Godoy; Naoki Hayashi; Mohamed A. Helal; Lucas G. Huggins; Abdul Jabbar; Rhys A. Jones; Benedict E. Karani; Juan Pedro Liron; Laura Maté; Amanda McEvoy; Khalid M. Mohammedsalih; Grace Mulcahy; Martin K. Nielsen; Barbora Pafčo; Laura E. Peachey; Joby Robleto-Quesada; Georg von Samson-Himmelstjerna; Lucas C. de Sousa-Paula; John S. Gilleard
    International Journal for Parasitology, Elsevier BV, Nov. 2025, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Mitogenomics of the tropical bont tick Amblyomma variegatum reveals vertical and horizontal transmission of Rickettsia africae
    Elisha Chatanga; Wessam Mohamed Ahmed Mohamed; Samuel Kelava; Naoki Hayashi; Yuma Ohari; Mohamed Abdallah Mohamed Moustafa; Joseph W. Magona; Kyoko Hayashida; Yongjin Qiu; Nariaki Nonaka; Ryo Nakao
    PLOS Neglected Tropical Diseases, 19, 10, e0013610, e0013610, Public Library of Science (PLoS), 21 Oct. 2025, [Peer-reviewed]
    English, Scientific journal, Background

    The tropical bont tick Amblyomma variegatum, which is widespread in Africa and the Caribbean islands, is of both medical and veterinary importance as the principal vector of intracellular bacterial pathogens Ehrlichia ruminantium , causing heartwater in animals, and Rickettsia africae , causing African tick bite fever (ATBF) in humans. This tick species is highly invasive and has been reported to expand its geographical distribution as well as host range. Rickettsia africae is also recognized as a common endosymbiont in A. variegatum , but its transmission dynamics within this tick population remain poorly understood.

    Methodology

    To investigate the co-phylogenetic patterns between A. variegatum and R. africae , we sequenced the complete mitogenomes of A. variegatum and performed multi-locus sequence typing (MLST) of six housekeeping genes of R. africae . The resulting sequence data were used to examine the hypothesis that R. africae is predominantly transmitted vertically within A. variegatum populations, which would lead to congruent phylogenies between vector and pathogen.

    Results

    There was geographical population sub-structing in the mitogenomes of A. variegatum . The prevalence of R. africae in the examined ticks was 100%. The tanglegram showed non-strict co-cladogenesis between A. variegatum and R. africae . Furthermore, the Procrustes Application to Cophylogenetic (PACo) analysis and residuals of vector-pathogen associations showed no statistically significant association between A. variegatum and R. africae genotypes.

    Conclusions

    This study was the first to examine the spread of pathogenic/endosymbiotic bacterium R. africae in the A. variegatum populations using a mitogenomic approach. The results support both vertical and horizontal transmission of R. africae within A. variegatum . These findings also highlight the potential of R. africae to adapt to multiple animal species, which may complicate efforts to control it as a human pathogen.
  • Molecular characterization of Rhipicephalus microplus and tick-borne pathogens in cattle in Nepal
    Gita Sadaula Pandey; Chet Raj Pathak; Amir Sadaula; Prajwol Manandhar; Rabin Bastakoti; Mackenzie L. Kwak; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    Veterinary Research Communications, 49, 6, Springer Science and Business Media LLC, 04 Oct. 2025, [Peer-reviewed]
    English, Scientific journal
  • Efferocytosis-Driven M2 Macrophage Impairs Fibrotic Encapsulation and Promotes Echinococcus multilocularis Growth in Cotton Rats (Sigmodon hispidus)
    Maru Manabe; Teppei Nakamura; Keisuke Sato; Naoki Hayashi; Hirokazu Kouguchi; Ryo Nakao; Masahito Hidaka; Hiroyuki Matsuyama; Nariaki Nonaka; Masami Morimatsu
    Microscopy and Microanalysis, 31, 5, Oxford University Press (OUP), 03 Sep. 2025, [Peer-reviewed]
    English, Scientific journal, Abstract

    Alveolar echinococcosis, caused by Echinococcus multilocularis, exhibits significant species-dependent susceptibility. This study compared the early hepatic tissue responses to E. multilocularis in highly susceptible cotton rats (Sigmodon hispidus) and laboratory mice (DBA/2 and AKR/N). Following oral administration of E. multilocularis eggs, cotton rats developed a greater number of hepatic lesions within 2 weeks, whereas mice required 4 weeks to develop smaller lesions. Histopathology revealed accelerated multilocular cyst formation in cotton rats. Unlike mice, which formed dense collagenous layers isolating cysts, cotton rats lacked adventitial layers despite similar fibrotic thickness. Immunohistochemistry revealed abundant CD206+ macrophages at cyst peripheries in cotton rats, engaging in efferocytosis of apoptotic neutrophils with expression of TGF-β, galectin-3, and VEGF. Efferocytic macrophages expressed collagen-degrading enzymes (cathepsin K and MMP9) and the growth factor FGF2. These findings suggest that efferocytosis by neutrophils drives macrophages toward an anti-inflammatory M2 phenotype, leading to immune evasion, ineffective fibrotic encapsulation, and parasitic growth. Given the wide distribution of cotton rats in the Americas and the expanding range of E. multilocularis, their hypersusceptibility raises significant public health concerns as rodents could serve as an intermediate host. These insights may inform new strategies for host–parasite interactions and the control of alveolar echinococcosis.
  • Investigation of potentially zoonotic Rickettsia species in dogs and their attached ticks in the lens of One Health
    Elisha Chatanga; Henson Kainga; John Kothowa; Michael Luwe; Richard Ssuna; Tinotenda Razemba; Laston Chimaliro; Naoki Hayashi; Yuki Ohsugi; Yongjin Qiu; Kyoko Hayashida; Nariaki Nonaka; Ryo Nakao
    Science in One Health, 100122, Elsevier BV, Sep. 2025, [Peer-reviewed]
    English, Scientific journal
  • What’s bugging Himalayan big cats: vector-borne pathogens of wild tigers and leopards in Nepal
    Gita Sadaula Pandey; Amir Sadaula; Abdelbaset Eweda Abdelbaset; Prajwol Manandhar; Pradeepa Silwal; Bijaya Kumar Shrestha; Yuki Ohsugi; Yongjin Qiu; Mackenzie L. Kwak; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    European Journal of Wildlife Research, 71, 5, 92, Springer Science and Business Media LLC, 07 Aug. 2025, [Peer-reviewed]
    English, Scientific journal
  • Phylogenetic characterization of the pork tapeworm Taenia solium in Japan: implications for the enigmatic evolutionary history
    Naoki Hayashi; Ryo Kuwamoto; Mitsuhiro Okada; Kenta Suzuki; Takaya Hoketsu; Samuel Kelava; Yuma Ohari; Munehiro Okamoto; Kinpei Yagi; Nariaki Nonaka; Ryo Nakao
    International Journal for Parasitology, Apr. 2025, [Peer-reviewed], [Lead author]
    English, Scientific journal, 49639990
  • Genetic diversity and population structure of Fasciola gigantica isolated from cattle in Malawi
    Lenson Mogha; Henson Kainga; Nathan Kamanga; Thoko Flav Kapalamula; Catherine Wood; Lian F. Thomas; Florence Mutua; Neil Sargison; Kyoko Hayashida; Taiga Tsutsumi; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao; Elisha Chatanga
    Veterinary Research Communications, 49, 157, Apr. 2025, [Peer-reviewed]
    English, Scientific journal
  • Strongyle nematode fauna in three ruminants in upper northern Thailand
    Thanakorn Rompo; Naoki Hayashi; Ernest Teo; Tawatchai Singhla; Chakorn Kunkaew; Duanghatai Sripakdee; Boondarika Nambooppha; Saruda Wanganurakkul; Kanthanis Limwibulpong; Kanyatip Sangarun; Napatsorn Suwongsaksri; Saravalee Suphakarn; Chanakan Chotiphutthikul; Yuto Matsui; Takao Irie; Ayako Yoshida; Lerdchai Chintapitaksakul; Naoaki Misawa; Nariaki Nonaka; Ryo Nakao; Saruda Tiwananthagorn
    Parasitology International, 103057, 103057, Elsevier BV, Mar. 2025, [Peer-reviewed]
    English, Scientific journal
  • Patterns of intestinal parasite prevalence in brown bears (Ursus arctos) revealed by a 3-year survey on the Shiretoko Peninsula, Hokkaido, Japan
    Mizuki Moriyoshi; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao; Masami Yamanaka; Toshio Tsubota; Michito Shimozuru
    International Journal for Parasitology: Parasites and Wildlife, 101048, 101048, Elsevier BV, Feb. 2025, [Peer-reviewed]
    English, Scientific journal
  • Exploring tick-borne pathogens in community dogs in Nepal
    Gita Sadaula Pandey; Chet Raj Pathak; Sunil Thapa; Amir Sadaula; Prajwol Manandhar; Abdelbaset Eweda Abdelbaset; Yongjin Qiu; Mackenzie L. Kwak; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    Parasitology International, 103003, 103003, Elsevier BV, Dec. 2024, [Peer-reviewed]
    English, Scientific journal
  • Synergistic Effects of Anti-echinococcosis Drug Candidates Combined With Atovaquone in Culture Assays and Mice With Primary Infections of Echinococcus multilocularis
    Hirokazu Kouguchi; Masahito Hidaka; Hiroyuki Matsuyama; Naoki Hayashi; Tomohito Koyano; Ryo Nakao; Nariaki Nonaka; Kinpei Yagi; Shigehiro Enkai
    Cureus, 16, 11, e74324, Springer Science and Business Media LLC, 23 Nov. 2024, [Peer-reviewed]
    Scientific journal
  • Detection and characterization of vector-borne parasites and Wolbachia endosymbionts in greater one-horned rhinoceros (Rhinoceros unicornis) in Nepal.
    Gita Pandey Sadaula; Prajwol Manandhar; Bijaya Kumar Shrestha; Amir Sadaula; Naoki Hayashi; Abdelbaset Eweda Abdelbaset; Pradeepa Silwal; Toshio Tsubota; Mackenzie L Kwak; Nariaki Nonaka; Ryo Nakao
    Acta tropica, 107344, 107344, 01 Aug. 2024, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Vector-borne parasite infections affect both domestic and wild animals. They are often asymptomatic but can result in fatal outcomes under natural and human-induced stressors. Given the limited availability of molecular data on vector-borne parasites in Rhinoceros unicornis (greater one-horned rhinoceros), this study employed molecular tools to detect and characterize the vector-borne parasites in rescued rhinoceros in Chitwan National Park, Nepal. Whole blood samples were collected from thirty-six R. unicornis during rescue and treatment operations. Piroplasmida infections were first screened using nested polymerase chain reaction (PCR) targeting 18S ribosomal RNA gene. Wolbachia was detected by amplifying 16S rRNA gene, while filarial nematodes were detected through amplification of 28S rRNA, COI, myoHC and hsp70 genes. Our results confirmed the presence of Theileria bicornis with a prevalence of 75% (27/36) having two previously unreported haplotypes (H8 and H9). Wolbachia endosymbionts were detected in 25% (9/36) of tested samples and belonged to either supergroup C or F. Filarial nematodes of the genera Mansonella and Onchocerca were also detected. There were no significant association between T. bicornis infections and the age, sex, or location from which the animals were rescued. The high prevalence of Theileria with novel haplotypes along with filarial parasites has important ecological and conservational implications and highlights the need to implement parasite surveillance programs for wildlife in Nepal. Further studies monitoring vector-borne pathogens and interspecies transmission among wild animals, livestock and human are required.
  • Case report: Echinococcus multilocularis infection in a dog showing gastrointestinal signs in Hokkaido, Japan
    Izumi Kida; Naoki Hayashi; Nozomu Yokoyama; Noriyuki Nagata; Kazuyoshi Sasaoka; Noboru Sasaki; Keitaro Morishita; Kensuke Nakamura; Hirokazu Kouguchi; Kinpei Yagi; Ryo Nakao; Mitsuyoshi Takiguchi; Nariaki Nonaka
    Frontiers in Veterinary Science, 11, Jun. 2024, [Peer-reviewed]
    English, Scientific journal
  • A survey of gastrointestinal helminth infestation in smallholder backyard pigs and the first molecular identification of the two zoonotic helminths Ascaris suum and Trichuris suis in Myanmar
    Saw Bawm; Lat Lat Htun; Hla Myet Chel; Yadanar Khaing; Myint Myint Hmoon; Su Su Thein; Shwe Yee Win; Nyein Chan Soe; Yu Nandi Thaw; Naoki Hayashi; Mar Mar Win; Nariaki Nonaka; Ken Katakura; Ryo Nakao
    BMC Veterinary Research, 20, 1, Springer Science and Business Media LLC, 06 Apr. 2024, [Peer-reviewed]
    Scientific journal, Abstract

    Background

    Parasitic infestations have a substantial economic impact on pig production. This study aimed to investigate the gastrointestinal (GI) helminths in pigs and to molecularly characterise two important nematodes, Ascaris and Trichuris species.

    Materials and methods

    A total of 500 pig faecal samples were collected from small holder backyard pig farms in five townships within Nay Pyi Taw, Myanmar. Microscopic examination was conducted to estimate the prevalence of GI helminth infestation in the pigs. DNA extraction and PCR were performed on faecal samples that were morphologically positive for Ascaris and Trichuris eggs. Molecular analysis was then conducted to characterise A. suum and T. suis, the most common and zoonotic helminths.

    Results

    According to microscopic examination, 69.2% (346/500) were positive for GI helminth eggs. The GI helminth species observed were A. suum, Strongyle, Strongyloides spp., T. suis, Metastrongylus spp., Hyostrongylus spp., Fasciolopsis spp., Paragonimus spp., and Schistosoma spp., with occurrences of 34.8%, 29.6%, 21.4%, 20.0%, 4.0%, 1.6%, 1.0%, 1.0%, and 0.4%, respectively. Mixed infections of GI helminths were noted in 31.0% of the samples. Overall, sampled pigs excreted mostly low levels (< 100 EPG) or moderate levels (> 100–500 EPG) of GI helminth eggs. The highest mean EPG for each parasite species was noted in A. suum. The presence of A. suum and T. suis was confirmed molecularly. The sequences of the internal transcribed spacer 1 (ITS1) region of A. suum showed high similarity with previously reported sequences. Likewise, the sequences of T. suis exhibited high similarity with the sequences reported from humans and pigs. Age was noted as an associated factor (P < 0.05) for GI helminth infection status.

    Conclusions

    In this report, A. suum and T. suis were molecularly identified for the first time in Myanmar. It is important to extend the information among the farmers to be aware of the necessity of preventing zoonotic parasites by practicing regular deworming, proper use of anthelmintics and maintaining hygienic conditions in their pig farms.
  • A filarial parasite potentially associated with the health burden on domestic chickens in Japan
    Naoki Hayashi#; Kumiko Hosokawa#; Yu Yamamoto; Sachiko Kodama; Aoi Kurokawa; Ryo Nakao; Nariaki Nonaka; (#:equal contribution)
    Scientific Reports, 14, 1, Springer Science and Business Media LLC, 15 Mar. 2024, [Peer-reviewed], [Lead author]
    English, Scientific journal, Abstract

    Chickens in free-range environments are at risk of exposure to various pathogens, such as filarioids transmitted via hematophagous vectors. However, the study of filarioids in poultry has been largely neglected compared to the extensive studies focused on viruses, bacteria, and protozoa. Here, we performed histological and molecular investigations of the filarioids detected in domestic chickens from two different flocks in Hiroshima Prefecture, Japan. In the first case, adult worms were present in the pulmonary artery and right ventricle, and microfilariae were present in multiple organs of deceased chickens. In the second case, similar filarioids were detected in the organs and blood of one necropsied layer. Phylogenetic analysis using 18S rRNA gene fragments positioned the filarioid in the same clade as that of Onchocercidae sp., previously identified in a deceased chicken from Chiba Prefecture, Japan, that is located 500 km away from Hiroshima Prefecture. Based on 28S rRNA and mitochondrial COI gene fragments, the filarioid was positioned distinctly from previously reported genera of avian filarioids. These results suggest that the filarioids are potentially associated with the health burden on domestic chickens and belong to the genus Paronchocerca. Furthermore, we developed a nested PCR assay targeting mitochondrial COI and detected the parasite DNA from the biting midge Culicoides arakawae captured near the flock, suggesting that it serves as a vector. Our findings fill the knowledge gap regarding avian filarioids, laying the groundwork for future studies examining the epidemiology, life cycle, and species diversity of this neglected parasite group.
  • Experimental demonstration of the transmission of Spiroplasma between different arthropod taxa
    Shohei Ogata; Naoki Hayashi; Yuki Eshita; Yasuha Nagasawa; Nariaki Nonaka; Ryo Nakao
    Journal of Medical Entomology, Oxford University Press (OUP), 21 Feb. 2024, [Peer-reviewed]
    English, Scientific journal, Abstract

    Spiroplasma (Mycoplasmatales: Spiroplasmataceae) is one of the most widely distributed symbionts of arthropods. Spiroplasma species can infect their hosts via vertical or horizontal transmission. However, the mode of transmission of Spiroplasma between different arthropod taxa has not been elucidated. In this study, we investigated the potential for the transmission of Spiroplasma to non-native arthropod species, using 2 Spiroplasma spp. isolated from ticks, namely Spiroplasma ixodetis and Spiroplasma mirum, and 3 species of mosquito laboratory colonies, namely Aedes albopictus, Aedes aegypti, and Culex pipiens pallens (Diptera: Culicidae). After feeding the adult mosquitoes with Spiroplasma-containing artificial meals, they were kept at 25 °C for 10 days. Homogenates prepared from Spiroplasma-fed mosquitoes were used to re-isolate Spiroplasma using the in vitro culture method. Nine weeks after culture initiation, the presence of Spiroplasma was tested using the polymerase chain reaction (PCR). The results revealed that only S. ixodetis was detected from all 3 species of mosquitoes and re-isolated from 2 of them. The differences in the infection ability of different Spirolasma species could be attributed to several factors, including environmental effects. Nevertheless, this is the first experimental demonstration of Spiroplasma transmission among different arthropod taxa. Further studies are needed to elucidate the evolutionary mechanism that supports the survival of Spiroplasma in nature.
  • Investigation of vertical and horizontal transmission of Spiroplasma in ticks under laboratory conditions
    Shohei Ogata; Rika Umemiya-Shirafuji; Kodai Kusakisako; Keita Kakisaka; Elisha Chatanga; Naoki Hayashi; Yurie Taya; Yuma Ohari; Gita Sadaula Pandey; Abdelbaset Eweda Abdelbaset; Yongjin Qiu; Keita Matsuno; Nariaki Nonaka; Ryo Nakao
    Scientific Reports, 13, 1, Springer Science and Business Media LLC, 15 Aug. 2023, [Peer-reviewed]
    English, Scientific journal, Abstract

    Many arthropods harbour bacterial symbionts, which are maintained by vertical and/or horizontal transmission. Spiroplasma is one of the most well-known symbionts of ticks and other arthropods. It is still unclear how Spiroplasma infections have spread in tick populations despite its high prevalence in some tick species. In this study, Ixodes ovatus, which has been reported to harbour Spiroplasma ixodetis at high frequencies, was examined for its vertical transmission potential under experimental conditions. Next, two isolates of tick-derived Spiroplasma, S. ixodetis and Spiroplasma mirum, were experimentally inoculated into Spiroplasma-free Haemaphysalis longicornis colonies and the presence of Spiroplasma in their eggs and larvae was tested. Our experimental data confirmed that S. ixodetis was transmitted to eggs and larvae in a vertical manner in the original host I. ovatus. In the second experiment, there was no significant difference in engorged weight, egg weight, and hatching rate between Spiroplasma-inoculated and control H. longicornis groups. This suggested that Spiroplasma infection does not affect tick reproduction. Spiroplasma DNA was only detected in the eggs and larvae derived from some individuals of S. ixodetis-inoculated groups. This has demonstrated the potential of horizontal transmission between different tick species. These findings may help understand the transmission dynamics of Spiroplasma in nature and its adaptation mechanism to host arthropod species.
  • Mitogenomic exploration supports the historical hypothesis of anthropogenic diffusion of a zoonotic parasite Echinococcus multilocularis
    Naoki Hayashi; Ryo Nakao; Yuma Ohari; Takao Irie; Hirokazu Kouguchi; Elisha Chatanga; Wessam Mohamed Ahmed Mohamed; Mohamed Abdallah Mohamed Moustafa; Gohta Kinoshita; Munehiro Okamoto; Kinpei Yagi; Nariaki Nonaka
    iScience, 107741, 107741, Elsevier BV, Aug. 2023, [Peer-reviewed], [Lead author]
    English, Scientific journal
  • Comparative mitogenomics elucidates the population genetic structure of Amblyomma testudinarium in Japan and a closely related Amblyomma species in Myanmar
    Wessam Mohamed Ahmed Mohamed; Mohamed Abdallah Mohamed Moustafa; May June Thu; Keita Kakisaka; Elisha Chatanga; Shohei Ogata; Naoki Hayashi; Yurie Taya; Yuma Ohari; Doaa Naguib; Yongjin Qiu; Keita Matsuno; Saw Bawm; Lat Lat Htun; Stephen C. Barker; Ken Katakura; Kimihito Ito; Nariaki Nonaka; Ryo Nakao
    Evolutionary Applications, 15, 7, 1062, 1078, Wiley, 23 Jun. 2022, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Ticks are the second most important vector capable of transmitting diseases affecting the health of both humans and animals. Amblyomma testudinarium Koch 1844 (Acari: Ixodidae), is a hard tick species having a wide geographic distribution in Asia. In this study, we analyzed the composition of A. testudinarium whole mitogenomes from various geographical regions in Japan and investigated the population structure, demographic patterns, and phylogeographic relationship with other ixodid species. In addition, we characterized a potentially novel tick species closely related to A. testudinarium from Myanmar. Phylogeographic inference and evolutionary dynamics based on the 15 mitochondrial coding genes supported that A. testudinarium population in Japan is resolved into a star-like haplogroup and suggested a distinct population structure of A. testudinarium from Amami island in Kyushu region. Correlation analysis using Mantel test statistics showed that no significant correlation was observed between the genetic and geographic distances calculated between the A. testudinarium population from different localities in Japan. Finally, demographic analyses, including mismatch analysis and Tajima's D test, suggested a possibility of recent population expansion occurred within Japanese haplogroup after a bottleneck event. Although A. testudinarium has been considered widespread and common in East and Southeast Asia, the current study suggested that potentially several cryptic Amblyomma spp. closely related to A. testudinarium are present in Asia.
  • Morphological and molecular identification of trematode cercariae related with humans and animal health in freshwater snails from a lake and a dam in Myanmar.
    Saw Bawm; Nang Hnin Ei Khaing; Shwe Yee Win; Su Su Thein; Yadanar Khaing; Yu Nandi Thaw; Nyein Chan Soe; Hla Myet Chel; Myint Myint Hmoon; Naoki Hayashi; Lat Lat Htun; Ken Katakura; Nariaki Nonaka; Ryo Nakao
    Parasitology research, 121, 2, 653, 665, Feb. 2022, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Freshwater snails play an essential role in the transmission of trematode parasitic flatworms that can infect wild and domestic animals, as well as humans. This study aimed to investigate the rate of cercarial infections in freshwater snails collected from two study areas, Inlay Lake and Yezin Dam, in Myanmar. A total of 4,740 snail samples were collected from Inlay Lake (n = 3,837) and Yezin Dam (n = 903), and infection rate by cercarial emergence was examined. Cercarial DNA samples were analysed by PCR. Based on morphological characteristics, eleven snail species and eight cercarial types were identified. Snails of Melanoides tuberculata in the family Thiaridae were found as the most abundant, followed by Indoplanorbis exustus of the family Planorbidae, in both study areas. The infection rate by cercarial emergence in snails in Inlay Lake and Yezin Dam was 5.8% (224/3,837) and 48.6% (439/903), respectively. Echinostome cercariae showed the highest infection rate in both study areas. Phylogenetic analysis of cercarial internal transcribed spacer 2 (ITS2) sequences revealed that at least seven cercaria types belonged to five digenean trematode families, two of which were zoonotic trematodes in the families of Opisthorchiidae/Heterophyidae and Schistosomatidae. Furthermore, cercarial 28S ribosomal RNA gene analysis showed that the furcocercous cercariae in Yezin Dam were identified as Schistosoma spindale, a causative agent of ruminant schistosomiasis. This is the first report on zoonotic trematode cercariae in snails in Myanmar. The findings indicate that various snail species act as intermediate host for trematode species that infect aquatic animals, mammals and humans in the country.
  • The strong influence of management factors on coccidian infections in smallholder pig farms and the first molecular identification of Cystoisospora suis in Myanmar.
    Saw Bawm; Hla Myet Chel; Yadanar Khaing; Myint Myint Hmoon; Su Su Thein; Shwe Yee Win; Nyein Chan Soe; Yu Nandi Thaw; Naoki Hayashi; Mar Mar Win; Lat Lat Htun; Nariaki Nonaka; Ken Katakura; Ryo Nakao
    Parasite (Paris, France), 29, 1, 1, 2022, [Peer-reviewed], [International Magazine]
    English, Scientific journal, A cross-sectional study was conducted to investigate coccidian infection and associated factors in smallholder pigs, and to identify Cystoisospora oocysts by PCR. A total of 500 pig faecal samples from 330 smallholder farms were collected in Nay Pyi Taw, Myanmar. The faecal flotation method was used to identify Eimeria and Cystoisospora species, and oocyst counts per gram (OPG) of faeces were recorded. Oocysts were differentiated after sporulation. Oocyst DNA was subjected to ITS1-targeted Cystoisospora-specific PCR. The overall coccidian oocyst detection rate by microscopic was 89.0% (445/500). Among the studied samples, 74.0% (370/500) and 70.6% (353/500), were found to be positive with Eimeria spp. and Cystoisospora suis oocysts, respectively. The sequences of C. suis detected were 100% identical to those of C. suis reported from Japan, and had 99.5% resemblance to sequences from Australia and China. Weaner pigs showed the significantly highest (p < 0.05) OPG when compared to other age groups. The highest intensity of coccidian infection (p < 0.05) was found in pigs fed local feed, pigs raised on earthen floors and pigs under poor hygienic conditions. Factors such as age, breed, feed type, and housing floors were found to be significantly associated with coccidian infection (p < 0.05). Age, as well as management factors including floor type, feed type, and hygiene practices on the farm, had a strong influence on the occurrence of coccidian infection in pigs. This is the first study in Myanmar on coccidian infection in pigs and molecular detection of C. suis.
  • Novel symbionts and potential human pathogens excavated from argasid tick microbiomes that are shaped by dual or single symbiosis.
    Mohamed Abdallah Mohamed Moustafa; Wessam Mohamed Ahmed Mohamed; Alice C C Lau; Elisha Chatanga; Yongjin Qiu; Naoki Hayashi; Doaa Naguib; Kozue Sato; Ai Takano; Keita Matsuno; Nariaki Nonaka; DeMar Taylor; Hiroki Kawabata; Ryo Nakao
    Computational and structural Biotechnology Journal, 20, 1979, 1992, 2022, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Research on vector-associated microbiomes has been expanding due to increasing emergence of vector-borne pathogens and awareness of the importance of symbionts in the vector physiology. However, little is known about microbiomes of argasid (or soft-bodied) ticks due to limited access to specimens. We collected four argasid species (Argas japonicus, Carios vespertilionis, Ornithodoros capensis, and Ornithodoros sawaii) from the nests or burrows of their vertebrate hosts. One laboratory-reared argasid species (Ornithodoros moubata) was also included. Attempts were then made to isolate and characterize potential symbionts/pathogens using arthropod cell lines. Microbial community structure was distinct for each tick species. Coxiella was detected as the predominant symbiont in four tick species where dual symbiosis between Coxiella and Rickettsia or Coxiella and Francisella was observed in C. vespertilionis and O. moubata, respectively. Of note, A. japonicus lacked Coxiella and instead had Occidentia massiliensis and Thiotrichales as alternative symbionts. Our study found strong correlation between tick species and life stage. We successfully isolated Oc. massiliensis and characterized potential pathogens of genera Ehrlichia and Borrelia. The results suggest that there is no consistent trend of microbiomes in relation to tick life stage that fit all tick species and that the final interpretation should be related to the balance between environmental bacterial exposure and endosymbiont ecology. Nevertheless, our findings provide insights on the ecology of tick microbiomes and basis for future investigations on the capacity of argasid ticks to carry novel pathogens with public health importance.
  • Early-phase migration dynamics of Echinococcus multilocularis in two mouse strains showing different infection susceptibilities.
    Naoki Hayashi; Hirokazu Kouguchi; Yuhei Imasato; Takao Irie; Kinpei Yagi; Nariaki Nonaka; Ryo Nakao
    International Journal for Parasitology, 51, 11, 893, 898, Oct. 2021, [Peer-reviewed], [Lead author], [International Magazine]
    English, Scientific journal, The early-phase migration dynamics of Echinococcus multilocularis in the intermediate hosts remain largely unknown. We compared the parasite burden in the intestine, liver and faeces of DBA/2 and C57BL/6 mouse strains using parasite-specific quantitative PCR. Our results indicated that the parasites invaded mainly from the middle segments of the small intestine and completed migration to the liver within 24 h p.i. C57BL/6 mice had lower parasite DNA burdens in the intestine and liver but higher in the faeces than DBA/2 mice, suggesting that parasite invasion of the intestine may be a critical stage regulating susceptibility to E. multilocularis infection in mice.
■ Other Activities and Achievements
  • Echinococcus multilocularis Genetic Analysis
    Naoki Hayashi, Mendeley Data, Jan. 2026
    This dataset contains DNA analysis methods for Echinococcus multilocularis, including DNA extraction protocols and procedures for constructing haplotype networks, associated with the review:
    Hayashi, N., Nakao, R., and Nonaka, N. 2026. Introduction and distributional expansion of Echinococcus multilocularis in Japan: a review from genetic perspectives. Japanese Journal of Veterinary Parasitology. 24:1-12., English, Introduction other
■ Lectures, oral presentations, etc.
  • マダニ共生細菌Rickettsiellaの宿主域推定と吸血生理への影響
    金子ちひろ; Jiménez PAJ; 大杉祐生; 田谷友里恵; 御子柴碧; 室谷晴彦; 邱永晋; 林直樹; 野中成晃; 中尾亮
    第70回日本応用動物昆虫学会大会, 30 Mar. 2026, Oral presentation
    28 Mar. 2026 - 30 Mar. 2026
  • Phylogenetic analysis of the pork tapeworm Taenia solium in wild boars in Nagano Prefecture, Japan: reconsideration of the “Out of Africa" hypothesis
    Naoki HAYASHI; Ryo KUWAMOTO; Mituhiro OKADA; Kenta SUZUKI; Takaya HOKETSU; Samuel KELAVA; Yuma OHARI; Munehiro OKAMOTO; Kinpei YAGI; Nariaki NONAKA; Ryo NAKAO
    73rd Annual Meeting of Ecological Society of Japan, 15 Mar. 2026, Japanese, Poster presentation
    11 Mar. 2026 - 15 Mar. 2026, 49639990;51913382
  • Genetic diversity and population structure of Echinococcus granulosus sensu lato in Kenya
    Erastus Mulinge; Ryo Nakao; Naoki Hayashi; Taiga Tsutsumi; Samuel Kevala; Eberhard Zeyhle; Cecilia Mbae; Marion Wassermann; Nariaki Nonaka
    16th KEMRI Annual Scientific and Health Conference (KASH), 11 Feb. 2026, English, Oral presentation
    10 Feb. 2026 - 13 Feb. 2026
  • Integrating nemabiome metabarcoding with fecal egg count reduction test for species-specific anthelminthic efficacy against strongylids nematodes in goats
    Thanakorn Rompo; Namboopha Boondarika; Singhla Tawatchai; Hayashi Naoki.; Nonaka Nariaki; Nakao Ryo; Saruda Tiwananthagorn
    The 1st Asia Pacific Veterinary Parasitology Congress, 06 Nov. 2025, English
    06 Nov. 2025 - 07 Nov. 2025
  • キツネ捕獲調査の代替としての糞便に基づく多包条⾍感染状況調査法の構築
    鈴木なお; 浦口宏二; 八木欣平; 林 直樹; 中尾 亮; 野中成晃
    第71回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 25 Oct. 2025, Japanese, Oral presentation
    25 Oct. 2025 - 25 Oct. 2025, 50789974
  • 北海道札幌市近郊の繁殖期における⿃類へのマダニ寄⽣動態とその影響要因の推定
    大杉祐生; 松井 晋; 原山法大; Ernest Teo; 伊藤萌林; 林 直樹; 野中成晃; 中尾 亮
    第71回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 25 Oct. 2025, Japanese, Oral presentation
    25 Oct. 2025 - 25 Oct. 2025
  • Helminthic Neglected Tropical Diseases in Japan
    Naoki Hayashi
    JSPS Core-to-Core Symposium “Establishment of a One-Health research network for controlling neglected tropical diseases (NTDs) in Sub-Saharan Africa.”, 09 Oct. 2025, English, Others
    09 Oct. 2025 - 09 Oct. 2025, 49639990
  • Genetic diversity and population structure of Echinococcus granulosus sensu lato in Kenya
    Erastus MULINGE; Ryo NAKAO; Naoki HAYASHI; Taiga TSUTSUMI; Eberhard ZEYHLE; Cecilia MBAE; Nariaki NONAKA
    XXX World Congress Echinococcosis, English, Oral presentation
    30 Sep. 2025 - 02 Oct. 2025
  • A high-throughput genotyping assay based on multiplex PCR followed by deep amplicon sequencing: a robust and non-invasive approach for assessing the genetic diversity of Echinococcus multilocularis in field samples
    Naoki HAYASHI; Sangarun KANYATIP; Yuki MIZUTANI; Hirokazu KOUGUCHI; Hiroyuki MATSUYAMA; Masahito HIDAKA; Kinpei YAGI; Nariaki NONAKA; Ryo NAKAO
    XXX World Congress Echinococcosis 2025, English, Oral presentation
    30 Sep. 2025 - 02 Oct. 2025, 50789974;47267510
  • Genetic investigation of the historical hypothesis on the anthropogenic introduction of Echinococcus multilocularis into Hokkaido, Japan
    Naoki HAYASHI; Ryo NAKAO; Yuma OHARI; Takao IRIE; Hirokazu KOUGUCHI; Elisha CHATANGA; Wessam MOHAMED; Mohamed MOUSTAFA; Gohta KINOSHITA; Munehiro OKAMOTO; Kinpei YAGI; Nariaki NONAKA
    XXX World Congress Echinococcosis 2025, English, Oral presentation
    30 Sep. 2025 - 02 Oct. 2025, 50789974;51158900;47267510
  • Temperature-Driven phenology of Amblyomma testudinarium associated with human tick bites in Hyogo, Japan
    Paula Andrea Jimenez Jimenez; Masaru Natsuaki; Mackenzie Kwak; Ernest Teo; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    The 13th Sapporo Summer Symposium for One Health (SaSSOH), English, Poster presentation
    25 Sep. 2025 - 26 Sep. 2025
  • Genetic characterization of equine strongyles in Hokkaido, Japan
    Takaya Hoketsu; Harutaka Murase; Akihiro Ochi; Takanori Ueno; Kazuhiro Kunii; Daiki Kishi; Hidekazu Niwa; Ryusei Onishi; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    The 13th Sapporo Summer Symposium for One Health (SaSSOH), English, Poster presentation
    25 Sep. 2025 - 26 Sep. 2025
  • Prevalence of tick-borne pathogens in ticks on Tobishima Island, Yamagata, Japan
    Yuki Ohsugi; Hirotaka Komine; Yongjin Qiu; Naoki Hayashi; Ryo Nakao; Nariaki Nonaka
    The 13th Sapporo Summer Symposium for One Health (SaSSOH), English, Poster presentation
    25 Sep. 2025 - 26 Sep. 2025
  • Pilot study on the persistence of Echinococcus multilocularis in red foxes (Vulpes vulpes) following anthelmintic baiting in Taiki town, Hokkaido: Microscopy and coproDNA surveillance
    Laston Chimaliro; Kanyatip Sangarun; Naoki Hayashi; Nao Suzuki; Tomihito Koyano; Tsusumi Taiga; Michihiko Saito; Fumio Kobayashi; Ryo Nakao; Nariaki Nonaka
    The 13th Sapporo Summer Symposium for One Health (SaSSOH), English, Poster presentation
    25 Sep. 2025 - 26 Sep. 2025, 47041003;47267510
  • Assessing the infectivity of Echinococcus multilocularis eggs from field-defecated fox feces across seasons
    Kanyatip Sangarun; Naoki Hayashi; Hirokazu Kouguchi; Takaya Hoketsu; Tomohito Koyano; Taiga Tsutsumi; Kohji Uraguchi; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    The 13th Sapporo Summer Symposium for One Health (SaSSOH), English, Oral presentation
    25 Sep. 2025 - 26 Sep. 2025, 47041003;47267510
  • 駆虫薬耐性獲得が疑われる馬の円虫種の分子学的同定
    法華津 孝哉; 村瀬 晴崇; 多田 健一郎; 越智 章仁; 国井 博和; 上野 孝範; 岸 大貴; 大村 一; 丹羽 秀和; 林 直樹; 野中 成晃; 中尾 亮
    The 168th meeting of the Japanese Society of Veterinary Science, 04 Sep. 2025, Japanese, Oral presentation
    03 Sep. 2025 - 04 Sep. 2025
  • Genetic revision of the African origin hypothesis for the pork tapeworm Taenia solium
    林 直樹; 桑本 亮; 岡田 充弘; 鈴木 健太; 法華津 孝哉; Samuel Kelava; 尾針 由真; 岡本 宗裕; 八木 欣平; 野中 成晃; 中尾 亮
    The 168th meeting of the Japanese Society of Veterinary Science, 04 Sep. 2025, Japanese, Oral presentation
    03 Sep. 2025 - 04 Sep. 2025, 49639990
  • Seasonal variation in the infectivity of Echinococcus multilocularis eggs in field-defecated fox feces and haplotype isolation via experimental infection in mice
    Kanyatip Sangarun; Naoki Hayashi; Hirokazu Kouguchi; Takaya Hoketsu; Tomohito Koyano; Taiga Tsutsumi; Kohji Uraguchi; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    The 168th meeting of the Japanese Society of Veterinary Science, 03 Sep. 2025, English, Oral presentation
    03 Sep. 2025 - 04 Sep. 2025, 47041003;47267510
  • Tick-associated rash illness (TARI): addressing a public health puzzle with lessons from Japan
    Paula Andrea Jiménez; Masaru Natsuaki; Ernest Teo; Mackenzie L. Kwak; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    The 2nd Southeast Asia Ticks and Tick-borne Diseases Symposium, 29 Aug. 2025, English, Oral presentation
    28 Aug. 2025 - 29 Aug. 2025
  • 道内で確定診断された乳頭糞線虫によるホルスタイン種育成牛の連続突然死
    池田哲平; 牧野康太郎; 丹治雅輝; 法華津孝哉; 金子ちひろ; 室谷晴彦; 林 直樹; 中尾 亮; 野中成晃
    令和７年度獣医学術学会北海道地区学会, 29 Aug. 2025, Japanese, Oral presentation
    28 Aug. 2025 - 29 Aug. 2025
  • 道内牧場における馬の葉状条虫に対するプラジカンテル耐性の疑い例
    法華津孝哉; 多田健一; 丹羽秀和; 大村一; 櫻井健太朗; 堤泰我; 大西龍生; 御子柴碧; 林直樹; 野中成晃; 中尾 亮
    令和７年度獣医学術学会北海道地区学会, 29 Aug. 2025, Japanese, Oral presentation
    28 Aug. 2025 - 29 Aug. 2025
  • Metagenomics of the tropical bont tick Amblyomma variegatum and co-evolution implications of its endosymbiont Rickettsia africae
    ELISHA CHATANGA; Wessam Mohamed; Ahmed Mohamed; Samuel Kelava; Naoki Hayashi; Yuma Ohari; Mohamed Abdallah Mohamed Moustafa; Joseph W Magonal; Kyoko Hayashida; Yongjin Qiu; Nariaki Nonaka; Ryo Nakao
    30th Conference of the World Association for the Advancement of Veterinary Parasitology, 20 Aug. 2025, English, Poster presentation
    17 Aug. 2025 - 21 Aug. 2025
  • A novel genotype of Taenia solium in Japan: public health implications and evolutionary insights
    Naoki Hayashi; Ryo Kuwamoto; Mitsuhiro Okada; Kenta Suzuki; Takaya Hoketsu; Samuel Kelava; Yuma Ohari; Okamoto Munehiro; Kinpei Yagi; Nariaki Nonaka; Ryo Nakao
    30th Conference of the World Association for the Advancement of Veterinary Parasitology, 19 Aug. 2025, English, Poster presentation
    17 Aug. 2025 - 21 Aug. 2025, 49639990
  • 日本産マダニにおけるRickettsiella共生細菌の保有状況調査と分離菌株のマダニへの移植試験
    金子ちひろ; Jiménez PAJ; 大杉祐生; 田谷友里恵; 御子柴碧; 室谷晴彦; 邱永晋; 林直樹; 野中成晃; 中尾亮
    第 32 回ダニと疾患のインターフェイスに関するセミナー 奥豊後竹田 岡城の里 SADI, 13 Jun. 2025, Japanese, Oral presentation
    13 Jun. 2025 - 15 Jun. 2025
  • Genetic diversity of Echinococcus multilocularis in Hokkaido, Japan: implications for the control
    Naoki Hayashi; Ryo Nakao; Nariaki Nonaka
    The 36th meeting of Clinical Parasitology, 14 Jun. 2025, Japanese, Oral presentation
    14 Jun. 2025 - 14 Jun. 2025, 51158900;47267510;47041003, [Invited]
  • Studies on the transmission dynamics of Spiroplasma in tick population
    Shohei Ogata, Rika Shirafuji-Umemiya, Kodai Kusakisako, Keita Kakisaka, Elisha Chatanga, Naoki Hayashi, Yurie Taya, Yuma Ohari, Gita Sadaula Pandy, Abdelbaset Eweda Abdelbaset, Yongjin Qiu, Keita Matsuno, Nariaki Nonaka, Ryo Nakao
    The 52nd Meeting of The Japanese Society of Mycoplasmology, 23 May 2025, Japanese, Oral presentation
    23 May 2025 - 24 May 2025
  • 多包条虫感染初期の肝組織応答におけるコトンラットと実験用マウスの種差
    Teppei Nakamura; Maru Manabe; Keisuke Sato; Naoki Hayashi; Hirokazu Kouguchi; Masahito Hidaka; Hiroyuki Matsuyama; Nariaki Nonaka; Masami Morimatsu
    The 72nd Annual Meeting of the Japanese Association for the Laboratory Animal Science, 23 May 2025, Japanese, Oral presentation
    21 May 2025 - 23 May 2025
  • Did the pork tapeworm Taenia solium disperse "out of Africa"? : revisiting the African origin hypothesis
    Naoki Hayashi, Ryo Kuwamoto2, Mitsuhiro Okada3, Kenta Suzuki2, Takaya Hoketsu1, Samuel Kelava1, Ohari Yuma4, Munehiro Okamoto5, Kinpei Yagi1, Nariaki Nonaka1, Ryo Nakao1
    The 94th annual meeting of the Japanese society of Parasitology, 18 Mar. 2025, Japanese, Oral presentation
    17 Mar. 2025 - 19 Mar. 2025, 49639990
  • Ecology, invasion, and dispersal of the zoonotic tapeworm Echinococcus multilocularis in Hokkaido, Japan
    Naoki Hayashi
    The 72 th Annual Meeting of the Ecological Society of Japan, 17 Mar. 2025, Japanese, Nominated symposium
    15 Mar. 2025 - 18 Mar. 2025, 51158900;47267510;47041003
  • 鳥類によるマダニ・T B Pの分散拡大および維持機構の解明
    大杉祐生; 林直樹; 野中成晃; 中尾亮
    北海道鳥学セミナー, 15 Feb. 2025, Japanese
    15 Feb. 2025 - 15 Feb. 2025
  • 馬における消化管寄生虫診断法の現状と今後の課題
    中尾亮; 法華津孝哉; 林直樹; 野中成晃
    生産地における軽種馬の疾病に関するシンポジウム講演抄録(Web), 2025
    2025 - 2025
  • Comparison of four fecal egg counting techniques for equine strongyles
    法華津孝哉; 村瀬晴崇; 国井博和; 林 直樹; 越智章仁; 岸 大貴; Mackenzie Kwak; 河合正人; 大村 一; 上野孝範; 野中成晃; 中尾 亮
    The 37th annual meeting of the Japanese society of Equine Science, 26 Nov. 2024, Japanese, Oral presentation
    25 Nov. 2024 - 26 Nov. 2024
  • 北海道大学におけるキツネへの駆虫薬散布によるエキノコックス 症感染源対策―省力化/効率化の検討―
    斎藤通彦; 林直樹; 浦口宏二; 中尾亮; 野中成晃
    Proceedings of the 68th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 26 Sep. 2024, Japanese, Oral presentation
    25 Sep. 2024 - 26 Sep. 2024
  • Molecular detection and characterization of piroplasm species in wild felids in Nepal
    Gita Sadaula Pandey; Amir Sadaula; Abdelbaset Eweda Abdelbase; Pradeepa Silwal; Bijaya Kumar Shrestha; Prajwol Manandhar; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao
    Proceedings of the 70th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 24 Sep. 2024, Japanese, Oral presentation
    24 Sep. 2024 - 25 Sep. 2024
  • チマダニ属若ダニの実験室内吸⾎試験：吸⾎源宿主DNAの測定と寄⽣蜂の検出
    白木雄翔; 田谷友里恵; 林直樹; 野中成晃; 中尾亮
    Proceedings of the 70th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 24 Sep. 2024, Japanese, Oral presentation
    24 Sep. 2024 - 25 Sep. 2024
  • 本邦におけるマダニ科９種の集団遺伝学的解析
    沼田栄花; 尾針由真; 邱永晋; 篠塚千恵子; 佐藤梢; 川端寛樹; 高野愛; 安藤秀二; 林直樹; 野中成晃; 中尾亮
    Proceedings of the 70th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 24 Sep. 2024, Japanese, Oral presentation
    24 Sep. 2024 - 25 Sep. 2024
  • Evaluation of infectivity of Echinococcus multilocularis eggs in the fox feces using DBA/2 mice
    Kanyatip Sangaru; Naoki Hayashi; Hirokazu Kouguchi; Takaya Hoketsu; Taiga Tsutsumi; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    The 167th meeting of the Japanese Society of Veterinary Science, 10 Sep. 2024, English, Oral presentation
    10 Sep. 2024 - 11 Sep. 2024, 47041003;47267510
  • Mitochondrial genomes of equine nematodes in Japan
    法華津 孝哉; 村瀬 晴崇; 越智 章仁; 上野 孝範; 岸 大貴; 林 直樹; 野中 成晃; 中尾 亮
    The 167th meeting of the Japanese Society of Veterinary Science, 10 Sep. 2024, Japanese, Oral presentation
  • Population genetic structure of Echinococcus multilocularis in Hokkaido
    林 直樹; 中尾 亮; 尾針 由真; 水谷 雄基; Kanyatip Sangarun; 入江 隆夫; 孝口 裕一; 日高 正人; 松山 紘之; 木下 豪太; 岡本 宗裕; 八木 欣平; 野中 成晃
    The 167th meeting of the Japanese Society of Veterinary Science, 10 Sep. 2024, Japanese, Oral presentation
  • Intestinal parasites in wild brown bears (Ursus arctos yesoensis) in Hokkaido
    森好 水希; 林 直樹; 野中 成晃; 中尾 亮; 山中 正実; 坪田 敏男; 下鶴 倫人
    The 167th meeting of the Japanese Society of Veterinary Science, 10 Sep. 2024, Japanese, Oral presentation
  • Assessment of Echinococcus multilocularis eggs infectivity in the fox feces collected from the roadside in Nakashibetsu, Hokkaido
    Kanyatip Sangarun; Naoki Hayashi; Kouguchi Hirokazu; Takaya Hoketsu; Tsutsumi Taiga; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    The 12th Sapporo Summer Symposium for One Health, 04 Sep. 2024, English, Poster presentation
    04 Sep. 2024 - 05 Sep. 2024
  • Phylogenetic analysis of Taenia solium detected from wild boars in Nagano, Japan
    Naoki Hayashi; Ryo Kuwamoto; Mitsuhiro Okada; Kenta Suzuki; Munehiro Okamoto; Kinpei Yagi; Nariaki Nonaka; Ryo Nakao
    The 15th helminth research meeting, 20 Aug. 2024, Japanese, Oral presentation
    19 Aug. 2024 - 20 Aug. 2024
  • Phylogenetic analysis of Taenia solium detected from wild boars in Nagano, Japan
    林直樹; 桑本亮; 岡田充弘; 鈴木健太; 八木欣平; 中尾亮; 野中成晃
    The 93rd annual meeting of the Japanese society of Parasitology, 09 Mar. 2024, Japanese, Oral presentation
    08 Mar. 2024 - 10 Mar. 2024
  • Genomic investigations on Echinococcus multilocularis in Japan: Advancing alveolar echinococcosis control through population genetics
    林直樹; 中尾亮; 尾針由真; 水谷雄基; Sangarun Kanyatip; 入江隆夫; 孝口裕一; 日高正人; 松山紘之; 木下豪太; 岡本宗裕; 八木欣平; 野中成晃
    The 93rd annual meeting of the Japanese society of Parasitology, 09 Mar. 2024, Japanese, Oral presentation
    08 Mar. 2024 - 10 Mar. 2024
  • Molecular detection and characterization of tick-borne hemoparasites in Rhinoceros unicornis (Greater One Horned Rhinoceros) of Nepal
    Gita Pandey Sadaula; Prajwol Manandhar; Amir Sadaula; Naoki Hayashi; Bijaya Kumar Shrestha; Pradeepa Silwal; Nariaki Nonaka; Ryo Nakao
    第69回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 14 Oct. 2023, English, Oral presentation
  • Tracing the origins of Echinococcus multilocularis in Hokkaido, Japan: Anthropogenic impacts on the diffusion
    林 直樹, 中尾 亮,尾針由真,入江隆夫,孝口裕一, 木下豪太,岡本 宗裕,八木 欣平, 野中 成晃
    第69回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 14 Oct. 2023, Japanese, Oral presentation
  • 長野県木曽地域の野生イノシシより検出された有鉤条虫Taenia solium： 本邦における生活環維持の可能性
    林 直樹; 桑本 亮; 岡田充弘; 鈴木健太; 八木欣平; 中尾 亮; 野中成晃
    The 166th meeting of the Japanese Society of Veterinary Science, 05 Sep. 2023, Japanese
    05 Sep. 2023 - 09 Sep. 2023
  • Tracing the origins of Echinococcus multilocularis in Hokkaido, Japan:  genetic validation of a historical hypothesis
    Naoki Hayashi; Ryo Nakao; Yuma Ohari; Takao Irie; Hirokazu Kouguchi; Elisha Chatanga; Wessam Mohamed; Mohamed Moustafa; Gohta Kinoshita; Munehiro Okamoto; Kinpei Yagi; Nariaki Nonaka
    29th International Conference of the World Association for the Advancement of Veterinary Parasitology, 23 Aug. 2023, English, Oral presentation
    20 Aug. 2023 - 24 Aug. 2023
  • 慢性消化器症状を主訴に2次診療施設に来院したエキノコックス症の犬の1例
    紀田 泉; 横山 望; 林 直樹; 中尾 亮; 野中 成晃; 笹岡 一慶; 永田 矩之; 佐々木 東; 森下 啓太郎; 中村 健介; 滝口 満喜
    Japanese College of Veterinary Internal Medicine, 26 Feb. 2023, Oral presentation
  • 共培養細胞種による多包条虫原頭節の発育比較と長期培養による成虫化
    Yasuha Nagasawa; Naoki Hayashi; Kouguchi Hirokazu; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    Proceedings of the 68th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 15 Oct. 2022
    15 Oct. 2022 - 15 Oct. 2022
  • マウス2 系統における多包条虫Echinococcus multilocularis 感染初期動態の比較
    Naoki Hayashi; Kouguchi Hirokazu; Yuhei Imasato; Takao Irie; Kinpei Yagi; Nariaki Nonaka; Ryo Nakao
    Proceedings of the 68th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 15 Oct. 2022
    15 Oct. 2022 - 15 Oct. 2022
  • Monitoring of strongyle nematode infection in a sheep farm in Hokkaido with assessment on drug resistance
    Thanakorn Rompo; Naoki Hayashi; Ryo Nakao; Nariaki Nonaka
    Proceedings of the 68th Joint Annual Meeting of Northern Branch of the Japanese Society of Parasitology and the Japan Society of Medical Entomology and Zoology, 15 Oct. 2022, English, Oral presentation
    15 Oct. 2022 - 15 Oct. 2022
  • 愛玩鶏（碁石チャボ）より検出された糸状虫の系統分類および生活環について
    林 直樹; 細川 久美子; 山本 佑; 児玉 幸子; 黒川 葵; 中尾 亮; 野中 成晃
    第165回日本獣医学会学術集会, 07 Sep. 2022
    06 Sep. 2022 - 08 Sep. 2022
  • Prevalence of gastrointestinal parasites in cattle and buffalos in Upper Northern Thailand
    Sripakdee Duanghatai; Kunkaew Chakorn; Singhla Tawatchai; Yuto Matsui; Naoki Hayashi; Nariaki Nonaka; Ryo Nakao; Yuma Ohari; Ayako Yoshida; Takao Irie; Wanganurakkul Saruda; Sangarun Kanyatip; Limwibulpong Kanthanis; Tiwananthagorn Saruda
    The 2nd SATREPs International Symposium, 26 Aug. 2022, English, Nominated symposium
    26 Aug. 2022 - 26 Aug. 2022
  • a
    林直樹; 入江隆夫; 尾針由真; 孝口裕一; Elisha Chatanga; 木下豪太; 八木欣平; 中尾亮; 野中成晃
    The 91th Annual Meeting of the Japanese Society of Parasitology, 29 May 2022
    28 May 2022 - 29 May 2022
  • マダニから分離したリケッチエラ共生菌が保有するビタミンB群代謝関連遺伝子群の特定
    大前日希; May June Thu; 林直樹; 今里裕平; 野中成晃; 中尾亮
    第67回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 02 Oct. 2021
    02 Oct. 2021 - 02 Oct. 2021
  • 北海道に分布する多包条虫Echinococcus multilocularisのミトゲノムにおける遺伝的多様性およびその北海道への移入、拡散に関する考察
    林 直樹; 入江 隆夫; 尾針 由真; 孝口 裕一; 木下 豪太; 八木 欣平; 中尾亮; 野中 成晃
    第67回日本寄生虫学会・日本衛生動物学会北日本支部合同大会, 02 Oct. 2021
    02 Oct. 2021 - 02 Oct. 2021
  • Genetic diversity of Echinococcus multilocularis in Hokkaido, Japan based on mitogenome sequences.
    Naoki Hayashi; Takao Irie; Yuma Ohari; Gohta Kinoshita; Hirokazu Kouguchi; Kinpei Yagi; Ryo Nakao; Nariaki Nonaka
    The 9th Sapporo Summer Symposium for One Health, Sep. 2021
    15 Sep. 2021 - 16 Sep. 2021
  • a
    林直樹; 入江隆夫; 尾針由真; 木下豪太; 孝口裕一; 八木欣平; 中尾亮; 野中成晃
    The 164th meeting of the Japanese Society of Veterinary Science, Sep. 2021
    07 Sep. 2021 - 13 Sep. 2021
  • Comparative analysis on the migration dynamics of Echinococcus multilocularis at the early stage of infection in two mouse strains.
    Naoki Hayashi; Ryo Nakao; Hirokazu Kouguchi; Yuhei Imasato; Takao Irie; Kinpei Yagi; Nariaki Nonaka
    8th Sapporo Summer Symposium for One Health, Sep. 2020
    16 Sep. 2020 - 17 Sep. 2020
  • Investigation of the intermediate host sites that block the invasion of Echinococcus multiocularis by analyzing the movement dynamics of oncospheres at the initial phase of infection
    Naoki Hayashi; Ryo Nakao; Hirokazu Kouguchi; Yuhei Imasato; Irie Takao; Kinpei Yagi; Nariaki Nonaka
    The 89th Annual Meeting of the Japanese Society of Parasitology, May 2020, Oral presentation
    30 May 2020 - 31 May 2020
■ Syllabus
  • 原虫病学・寄生虫病学実習, 2024年, 学士課程, 獣医学部
■ Research Themes
■ Academic and Social Contribution Activities/Other
Industrial Property RightsSocial Contribution ActivitiesMedia CoverageOthers
  • Apr. 2025 - Present
    Adviser, Hokkaido Universität Wandervogel Verein
    Hokkaido Universität Wandervogel Verein official website https://huwv.org/
  • Jun. 2025
    The 31st Ito Foundation Travel Grant for International Conference Participation
    https://ito-zaidan.jp/subsidy/
  • Apr. 2020 - Mar. 2024
    Hokkaido University WISE Program for One Health Frontier
    https://onehealth.vetmed.hokudai.ac.jp/
  • Mar. 2023
    Zoonosis Control Expert (ZCE)
    https://www.vetmed.hokudai.ac.jp/project/leading/en/program/course.html
  • Apr. 2021 - Mar. 2022
    北海道大学アンビシャス博士人材フェローシップ（SDGs）
    https://sites.google.com/elms.hokudai.ac.jp/ambitious-phd-fellow/home/list-of-program-students?authuser=0