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Volume 32, Number 12—December 2026

Dispatch

Wild Mice and Shrews as Natural Reservoirs of Emerging Tickborne Yezo Virus, Hokkaido, Japan, 2023–2025

Mebuki Ito, Yuma Ohari, Isshu Kojima1, Yume Mimura, Keita Mizuma2, Jingshu Li, Hayato Torisu, Shumpei Kamiyama, Tomoki Sakiyama3, Hironori Mieda, Naoya Matsumoto, Natsumi Iijima, Eri Fujii, Yasuko Orba, Kuniko Kawai, Satoshi D. Ohdachi, and Keita MatsunoComments to Author 
Author affiliation: Hokkaido University International Institute for Zoonosis Control, Sapporo, Japan (M. Ito, Y. Ohari, I. Kojima, Y. Mimura, K. Mizuma, J. Li, E. Fujii, Y. Orba, K. Matsuno); Hokkaido University Graduate School of Environmental Science, Sapporo (H. Torisu, T. Sakiyama, H. Mieda); Tokai University Graduate School of Biology, Sapporo (S. Kamiyama, K. Kawai); Sapporo Maruyama Zoo, Sapporo (N. Matsumoto, N. Iijima); Hokkaido University Institute of Low Temperature Science, Sapporo (S.D. Ohdachi)

Main Article

Figure 2

Phylogenetic tree of Yezo virus from study of wild mice and shrews as natural reservoirs of emerging tickborne Yezo virus, Hokkaido, Japan, 2023–2025. Tree was constructed based on the nucleotide sequence of the open reading frame of each segment. A) Small segment; B) medium segment; C) large segment. Sequences were aligned using the MUSCLE algorithm in Geneious Prime (https://www.geneious.com). Maximum-likelihood trees were constructed using the RAxML method with the general time-reversible with gamma rate categories and invariable sites. Bootstrap support value was calculated with 1,000 replicates. Yezo virus isolate T30T31, which was reported from western Russia (15), was used as the outgroup to determine the root but is not shown. Orange bold text indicates isolates obtained in this study, which are labeled by host species icons, collection site identification, and collection year. Green shading indicates the isolates from Japan from previous studies (1,4,9). Blue circles indicate nodes with >70% bootstrap values. Scale bars indicate nucleotide substitutions per site.

Figure 2. Phylogenetic tree of Yezo virus from study of wild mice and shrews as natural reservoirs of emerging tickborne Yezo virus, Hokkaido, Japan, 2023–2025. Tree was constructed based on the nucleotide sequence of the open reading frame of each segment. A) Small segment; B) medium segment; C) large segment. Sequences were aligned using the MUSCLE algorithm in Geneious Prime (https://www.geneious.com). Maximum-likelihood trees were constructed using the RAxML method with the general time-reversible with gamma rate categories and invariable sites. Bootstrap support value was calculated with 1,000 replicates. Yezo virus isolate T30T31, which was reported from western Russia (15), was used as the outgroup to determine the root but is not shown. Orange bold text indicates isolates obtained in this study, which are labeled by host species icons, collection site identification, and collection year. Green shading indicates the isolates from Japan from previous studies (1,4,9). Blue circles indicate nodes with >70% bootstrap values. Scale bars indicate nucleotide substitutions per site.

Main Article

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Main Article

1Current affiliation: Okayama University of Science Faculty of Veterinary Medicine, Imabari, Japan.

2Current affiliation: Tokyo University, Tokyo, Japan.

3Current affiliation: Umeå University, Umeå, Sweden.

Page created: September 05, 2026
Page updated: October 27, 2026
Page reviewed: October 27, 2026
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