We found a lineage of hepatitis E virus (HEV) within genotype IV, members of which were JSF-Tot03C, JSN-Sap-FH02C, JYN-Sap 01C, HE-JK4, JYN-Nii 02L, HE-JF3, HE-JA1, HE-JI4 from humans and swJ13-1 from swine, all from Japan. Interestingly, of 9 patients infected with the HEV of this lineage, 3 were with fulminant hepatitis, and another 3 were with considerably prolonged prothrombin time (17%, 40% and 44%). In addition, at least 6 patients showed bilirubin levels greater than 10 mg/dl. Although host factors (pregnancy for example) may contribute much to clinical phenotypes of HEV infections, our present results suggest that a viral factor may also play an important role therein.
