Independent introduction of transmissible F/D recombinant HIV-1 from Africa into Belgium and the Netherlands

Most HIV-1 subtype F viruses described so far have been isolated from indiv iduals originating in South America, Romania, or Central Africa. Previous s tudies have shown that subtype F viruses from these three areas can be dist inguished by phylogenetic tree analysis of various parts of the HIV genome. Subtype F strains circulating in Central Africa and classified as subgroup F2 and F3 have relatively large nucleotide distances from strains of subgr oup F1, which includes some African strains, along with strains from Romani a and South America. Subtype F strains have now appeared in Europe. In this study, we analyzed the complete gag gene and a large fragment of the pol g ene of seven strains of African origin that represent the three F subgroups . At least five of the seven strains appear to be intersubtype recombinants . Of four strains circulating in Belgium and the Netherlands, three were F/ D mosaics and the fourth harboured a G(gag)/GH(pol)/F-anv recombinant struc ture. Two of the three F/D mosaics showed identical breakpoints and were in dependently introduced in Belgium and the Netherlands. At least two of the mosaics were further transmitted. The remaining three strains of the seven we studied were isolated from individuals in Cameroon. Two included large o r smaller F1 fragments in gag and pol. The third strain was subtype D along the entire gag. and pol fragment. A parental African subtype F that showed no evidence for recombination was not found. (C) 2000 Academic Press.