Session 113Poster Presentations Molecular Epidemiology Session Day and Time: Tuesday 1:30 - 3:30 pm Room: Hall B
894 Biologic Features of HIV-1 Subtype A in West Africa: Emergence of a Novel Sub Subtype A3 P. Kanki*1, S. Thakore1, J. - L. Sankalé1, O. Obsasanjo1, D. Hamel1, S. M. Boup2 1Harvard Sch of Public Hlth, Boston, MA and 2Cheikh Anta Diop Univ, Dakar, Senegal
Background: A 17-yr prospective study (1985-2002) of high risk and HIV-infected women in Senegal, West Africa, have demonstrated the dynamics of HIV-1 CRF 02 A/G (Ibng) as the predominant HIV-1 infection. In studies of HIV-2 protection, we first observed a novel HIV-1 subtype A variant that was seen in dually infected individuals, significantly more frequently than the more common HIV-1 CRF 02 A/G virus. This seemed to indicate that HIV-2 protection was sensitive to viral characteristics of the infecting HIV-1 subtype.
Methods: Further genetic characterization of the gp120 and gag sequences of these women have allowed the identification of a novel subcluster of HIV-1 subtype A; termed sub subtype A3.
Results: This novel virus variant arose in the early 1990s and has been transmitted within the cohort in concert with the CRF A/G (Ibng) virus. Thirty-seven (37) sub subtype A3 viruses (9%) have been detected in the 17-yr study period. In addition, we have found novel recombinant viruses demonstrating A/G sequences with A3 sequences in the V3 region of the envelope indicative of a fitness advantage for this novel subtype cluster. Demographic, behavioral, and clinical features have been analyzed to determine if biological differences between these viruses can be further demonstrated.
Conclusions: Our data suggests that small genetic changes in HIV-1 viruses may be responsible for distinct and clinically relevant biologic differences. The emergence of these new viral variants in this high-risk population suggests that evolution towards biologically distinct and new HIV viruses is rapid and ongoing.
