| identification of hiv-1 group o infection--los angeles county, california, 1996. | the strains of hiv-1 that have caused the worldwide pandemic of acquired immunodeficiency syndrome (aids) have been designated as group m viruses. a group of hiv-1 viruses that also cause aids but that are characterized by extensive genetic divergence from group m strains have been identified recently and classified as group o viruses. group o viruses or serologic evidence of group o infection have been reported in patients from west and central africa (cameroon, gabon, niger, nigeria, senegal, ... | 1996 | 9132574 |