Genotyping of hepatitis E virus from Vietnam.

To identify the genotype of Vietnamese isolates of human hepatitis E virus (HEV), phylogenetic analysis was performed for the open reading frame (ORF) 1 and ORF2 nucleotide sequences of the viral genome. HEV was detected by RT-PCR in 9 out of 141 sera collected from patients with a diagnosis of acute sporadic hepatitis in Hanoi, Vietnam. All of them had sequences related most closely to genotype 4. In addition, the Vietnamese isolate had a single nucleotide insertion in the ORF 3 region, a characteristic reported for genotype 4 with the possible change of initiation of ORF 3 and ORF 2.