RT Journal Article SR Electronic(1) A1 Tanaka, Yasuhito A1 Takahashi, Kazuaki A1 Orito, Etsuro A1 Karino, Yoshiyasu A1 Kang, Jong-Hon A1 Suzuki, Kazuyuki A1 Matsui, Atsushi A1 Hori, Akiko A1 Matsuda, Hiroyuki A1 Sakugawa, Hiroshi A1 Asahina, Yasuhiro A1 Kitamura, Tsuneo A1 Mizokami, Masashi A1 Mishiro, ShunjiYR 2006 T1 Molecular tracing of Japan-indigenous hepatitis E viruses JF Journal of General Virology, VO 87 IS 4 SP 949 OP 954 DO https://doi.org/10.1099/vir.0.81661-0 PB Microbiology Society, SN 1465-2099, AB 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., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.81661-0