Six cases of acute hepatitis E occurred within 18 months around Gifu city in Japan, infected with mutually-independent hepatitis E virus strains

We experienced six cases of hepatitis E within 18 months around Gifu city. The phylogenetic analysis indicated that the 6 hepatitis E virus (HEV) strains were included in different lineages, respectively. One case showed marked symptoms of hepatitis and was infected with a genotype 4 Aichi/Shizuoka strain which is ordinary isolated from wild animal. The case had history of consuming raw pig liver. The fact may indicate that Aichi/Shizuoka strains are confined not only to wild animal but also to pig bred around Gifu city. Other 5 cases had no clear risk factor of acquiring HEV and did not show obvious symptoms of hepatitis. HEV infection may occur more commonly than we think by various HEV lineages from unknown reservoirs.