HEPATITIS-E VIRUS IN NEPAL - SIMILARITIES WITH THE BURMESE AND INDIANVARIANTS

Hepatitis E has been the predominant type of acute hepatitis in Nepal both in adults and children, in sporadic and epidemic forms. We examin ed six hepatitis E Virus (HEV) isolates obtained during an 8-year peri od, from 1987 to 1995, in the Kathmandu valley of Nepal. Analysis of p ortions of the putative helicase, polymerase and capsid genes demonstr ated close genetic relatedness among themselves (> 96.4% identity) and with the Burmese (> 95.5%) and Indian (> 95.3%) isolates, and less so with the African (> 94.4%) and the Chinese (> 91%) isolates within th e Asian genotype. Phylogenetic analysis placed the Nepali isolates in the Burma-India evolutionary branch and showed that the oldest isolate , TK78/87 was more similar to the Burmese isolates whereas the most re cent isolates were closer to the Indian ones. Assuming no frameshifts, the Nepali isolates showed high amino acid conservation, but also uni que changes when compared to other HEV isolates. Amino acid residue 61 4 of the capsid protein was identified as a possible marker to disting uish the Burma-Nepal-India from the China-Central Asian Republics subg enotype, and the Mexico genotype. (C) 1997 Published by Elsevier Scien ce B.V.