FIG.1.

Phylogenetic tree constructed by the neighbor-joining method based on the partial nucleotide sequence (326 nt; nt 123 to 448 of the HE-JA10 genome, accession no. AB089824) of the ORF1 region of 52 human and swine HEV isolates using an avian HEV (AY535004) as an outgroup. In addition to 26 reported human and swine HEV isolates of genotypes 1 to 3 whose entire or nearly entire sequence is known, 26 reported isolates of genotype 4 whose common 326-nt sequence is available, as well as the HE-JVN1 isolate obtained in the present study, were included for comparison, with accession numbers in parentheses. The HE-JVN1 isolate is indicated by boldface type for visual clarity. The HEV strains of Vietnamese origin are shown by a vertical bar. The previously reported HEV sequences of genotype 1 are indicated with abbreviations in accordance with the recent review article by Schlauder and Mushahwar (16): B1 and B2 from Burma; C1, C2, C3, C4, C5, and C6 from China; I1, I2, I3, and I4 from India; Ne1 from Nepal; and P1 and P2 from Pakistan. Asterisks denote swine HEV strains. Bootstrap values are indicated for the major nodes as a percentage of the data obtained from 1,000 resamplings (4).