Genetic heterogeneity of HIV type 1 subtypes in Kimpese, rural Democratic Republic of Congo

A relatively low and stable seroprevalence of HIV-1 was previously reported among pregnant women attending for antenatal care between 1988 and 1993 in Kimpese, a rural town in the Democratic Republic of Congo (DRC, formerly Z aire). To characterize the HIV-1 subtypes circulating in this area, we have examined a 330-bp fragment of the p17 region of the gag gene of HIV-1 stra ins obtained from 70 patients (55 mothers, 15 children), of whom 61 were ep idemiologically unlinked. Phylogenetic analyses revealed the existence of a t least seven HIV-1 subtypes within the Kimpese region. Among the 61 epidem iologically unlinked patients, subtype A was predominant and found in 29 (4 7.5%) individuals. Other subtypes cocirculating in this rural part of DRC i nclude subtypes C (1.6%), D (9.8%), F (3.2%), G (6.5%), H (21.3%), and J (4 .9%), Sequences from four patients did not duster with any of the currently documented HIV-1 subtypes, in analyses of fragments of both the gag (247 t o 330 bp, 197 bp, and 310 bp) and env (340 bp) genes. Overall, comparisons of the gag(p17) gene regions revealed high pairwise divergences (mean, 19.9 %; range, 1 to 46%), This level of gag(p17) gene variation in the DRC is co nsiderably greater than previously appreciated. These results are relevant for the molecular epidemiology of HIV-1 in Africa and for the design of a f uture vaccine against HIV-1 in this region.