MOLECULAR EPIDEMIOLOGY OF SOUTH-AFRICAN STRAINS OF HEPATITIS-A VIRUS - 1982-1996

Isolates of hepatitis A virus (HAV) are of a single serotype, with hum an isolates being categorised within four genotypes. In addition, ther e are three genotypes exclusively associated with Old World monkeys. I n some geographical regions, related isolates cluster suggesting endem ic spread of the virus, while in other regions several genotypes circu late. Virtually no data are available with regard to the genetic relat edness of South African (SA) strains of HAV. A 177 base segment within the VP1 region and a 168 base segment encompassing the putative VP1/P 2A junction of 20 clinical and one environmental wild-type isolate(s) of HAV from SA were amplified by reverse transcriptase-polymerase chai n reaction. The nucleotide sequences from the SA isolates showed >85% nucleic acid sequence identity with published sequences for HAV strain s from genotype I, with the majority of strains (81%) clustering withi n subgenotype IB and the remainder in subgenotype IA. A high degree of conservation was noted between the predicted amino acid sequences fro m SA clinical isolates and isolates from the rest of the world. Data p resented indicate that in SA there is a circulating population of ende mic HAVs from two distinct subgenotypes. This study provides valuable new data on the genetic relatedness of HAVs from southern Africa and t he distribution of subgenotype IB. (C) 1997 Wiley-Liss, Inc.