Sequence Analysis of HIV-1 Group O from Norwegian Patients Infected in the 1960s1

Abstract Three Norwegians, a couple and their daughter, died from AIDS in 1976 after up to 10 years of clinical manifestations of HIV infection (Lindboe et al., 1986, Acta Pathol. Microbiol. Immunol. Scand. 94, 117–123; Froland et al., 1988, Lancet i, 1344–1345). We here demonstrate the presence of HIV DNA in autopsy materials from the father and the daughter. In phylogenetic analysis, the obtained sequences of the HIV pol and vif genes clustered with the HIV-1 group O clade. The genotyping was confirmed by detection of antibodies against HIV-1 group O in blood samples from the father and the mother. That these and other early isolates of HIV-1 are very similar to the presently circulating viruses and not intermediates between the present subtypes, verifies that the latest common ancestor of HIV-1 existed long before the emergence of the present epidemic. The presence of HIV-1 group O 30 years ago suggests that the limited spread of these viruses, compared to HIV-1 group M viruses, is not due to a later emergence of the group O viruses.