HIV type 1 subtype C in Addis Ababa, Ethiopia

HIV-1 variants in different geographic regions have been phylogenetically classified into the genetic subtypes A-I and O on the basis of sequence differences in the V3 regions of their gp120 envelope genes. The existence of all HIV-1 subtypes except subtype I has been confirmed in Africa. This paper describes the distribution of HIV-1 subtypes in Ethiopia. The first Ethiopian AIDS case was reported in 1986 and the AIDS epidemic has now become a rapidly growing problem in Addis Ababa, the capital city. HIV-1 seroprevalence in the city is estimated to be 10-27% among pregnant women, 47-59% among prostitutes, and 7% among blood donors. Preliminary sequence data on a limited number of samples indicated the presence of subtype C in Addis Ababa in 1988. 94 sera collected from prostitutes, pregnant women, and blood donors during 1989-95 were analyzed to assess the distribution of HIV-1 subtypes in Addis Ababa. HIV-1 subtype C was identified in 93 of 94 cases. One case of subtype A virus was identified. Subtype C was also highly abundant also before the 1995 sera collection. Finally, the authors discuss how the Ethiopian subtype C sequences differ slightly from the consensus C sequence.