Prevalence of HIV-1 subtype O infection in Cameroon: preliminary results.

Reported here are the results of a serum study to determine the prevalence of HIV-1 subtype O infections in select individuals in Cameroon. Also evaluated were some rapid screening assays used to detect HIV-1 subtype O antibodies. Participants were recruited from many locations; serum samples were from pregnant women patients at hospitals commercial sex workers cluster sampling of the general populace army recruits and individuals attending a sexually transmitted disease (STD) clinic. Sera were tested for HIV-1 and HIV-2 using the enzyme immunoassay (EIA) 1 + 2 a second generation enzyme-linked immunosorbent assay (ELISA) and EIA 5180 an indirect ELISA. All positives were retested and then discriminated using the Clonatec HIV 1 + 2 antibody EIA. HIV-1 subtype O infections were suspected if EIA 1 + 2 was positive and/or EIA 5180 was positive and the Clonatec EIA 1 + 2 was negative or weakly positive. Of the 21 patients surveyed all tested positive using EIA 5180; 20 of 21 were positive using EIA 1 + 2; 15 of 20 were Clonatec EIA negative while 6 were weakly positive using Clonatec EIA. This study found that the prevalence of HIV-1 subtype O infection in Cameroon is 2.0% or less. This accounts for less than 10% of all HIV-1 cases in Cameroon. HIV-2 was not found in this study of 2868 people; prevalence of HIV-1 subtype O among the same sample was 0.6% (16/2868). Risk factors associated with HIV-1 subtype O appear to be similar to those of classic HIV infections and include tuberculosis and sexual promiscuity. The issue of vertical transmission of HIV-1 subtype O in pregnant women was raised by the author.