%0 Journal Article %A Tanaka, Yasuhito %A Takahashi, Kazuaki %A Orito, Etsuro %A Karino, Yoshiyasu %A Kang, Jong-Hon %A Suzuki, Kazuyuki %A Matsui, Atsushi %A Hori, Akiko %A Matsuda, Hiroyuki %A Sakugawa, Hiroshi %A Asahina, Yasuhiro %A Kitamura, Tsuneo %A Mizokami, Masashi %A Mishiro, Shunji %T Molecular tracing of Japan-indigenous hepatitis E viruses %D 2006 %J Journal of General Virology, %V 87 %N 4 %P 949-954 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.81661-0 %I Microbiology Society, %X The ancestor(s) of apparently Japan-indigenous strains of Hepatitis E virus (HEV) was probably of foreign origin, but it remains unclear when and from where it made inroads. In this study, 24 genotype 3 and 24 genotype 4 HEV strains recovered in Japan each showed a significant cluster, clearly distinct from those of foreign strains, in the phylogenetic tree constructed from an 821 nt RNA polymerase gene fragment. The evolutionary rate, approximately 0·8×10−3 nucleotide substitutions per site per year, enabled tracing of the demographic history of HEV and suggested that the ancestors of Japan-indigenous HEV had made inroads around 1900, when several kinds of Yorkshire pig were imported from the UK to Japan. Interestingly, the evolutionary growth of genotype 3 in Japan has been slow since the 1920s, whereas genotype 4 has spread rapidly since the 1980s. In conclusion, these data suggest that the indigenization and spread of HEV in Japan were associated with the popularization of eating pork. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.81661-0