Search for HIV-1 group O infection in Nigeria [letter]

The immunologically and genetically divergent group O strain of HIV-1 is thought to represent a separate introduction of HIV-1 infection into the human population. HIV-1 group O was first isolated in 1989 with most group O strain infections having been reported from people in Cameroon and Gabon. The proximity of Nigeria to Cameroon and the strategic location of Lagos make the city a useful sentinel for HIV-1 group O detection. 248 serum samples were selected from 2000 prostitutes and patients seen at sexually transmitted disease clinics between 1990-91 and 1994. Of 182 reactive specimens 61 were HIV Western blot positive 73 were indeterminate and 48 were negative. The remaining 66 samples were enzyme-linked immunoassay (EIA)-negative but had varying numbers of reactive bands. Further testing of all 248 samples at Abbott Laboratories with the Clonatech HIV (1+2) EIA and at the US Centers for Disease Control with the Genetic Systems HIV 1/2 EIA found no sample with group O reactivity.