Short report: phylogenetically distinct hepatitis E viruses in Pakistan.

Hepatitis E, which is enterically transmitted, is the most common cause of acute hepatitis in much of Asia. Phylogenetic analysis of several isolates of hepatitis E virus (HEV) from Asia suggests that transmission of this virus is geographically restricted. In Sarghoda, Pakistan, HEV Sar-55 was isolated from a 1987 outbreak. It belongs to the Central-Asian cluster of the Asian sub-genotype. We now report the complete sequence of a second Pakistan HEV from a 1988 outbreak in Abbottabad. The Abbottabad nucleotide sequence was compared with 15 other complete HEV sequences using statistical methods of phylogenetic analysis. The analysis showed that Abbottabad HEV belongs to the South Asia cluster of the Asian sub-genotype. The sequence differences of the 2 Pakistan isolates recovered only one year apart suggest that HEV of 2 distinct origins circulate in Pakistan.