Full-length sequences of two hepatitis E virus isolates representing an Eastern China-indigenous subgroup of genotype 4.

Although the majority of hepatitis E virus (HEV) infections in Japan are 'domestic' due to the presence of indigenous strains, there are still 'imported' cases as well. Among 83 patients with non-A, non-B and non-C acute liver diseases admitted to Saitama Medical University Hospital, 7 (8.4%) were positive for serum HEV-RNA, of whom 2 had a recent history of traveling to China, one to Xian and another to Shanghai. We determined the full-genome sequences of HEV from these 2 patients (isolate names are JKO-ChiSai98c and JYI-ChiSai01c, genotype 4 in both) for phylogenetic analyses. Initially, when compared only to the 13 full-genome sequences of genotype 4 so far reported, our 2 isolates were thought to be novel strains because they showed a significant genetic difference from the sequences known to date. However, when we included a set of short sequences (150 nt) recently reported from China in the comparison, we found that our 2 isolates represent a subgroup of genotype 4, which seems to be restricted to eastern China. In conclusion, the 2 HEV isolates reported here could serve as full-genome prototypes for an eastern China-indigenous subgroup of the genotype 4 HEV.