Discrepancies in HIV RNA viral load, using the AMPLICOR HIV Monitor Assay (version 1.0) and the Branched DNA Signal Amplification Assay, prompted us to analyze viral genetic sequences among 55 HIV-infected individuals residing in the suburban Maryland counties of Washington, DC. All study participants were either short-term visitors or recent immigrants to the United States (US) from Cameroon (2), Central African Republic (1), Congo (3), Ethiopia (17), Gabon (1), Gambia (1), Ghana (3), Guinea (1), Ivory Coast (4), Kenya (4), Nigeria (2), Sierra Leone (3), Tanzania (1), Togo (3), Uganda (5), Zambia (2), and Zimbabwe (2). RNA or DNA, extracted from plasma or PBMC collected in 1997-98, were analyzed for a 273-nucleotide region spanning the V3 loop of the gp120-encoding HIV env gene by nested PCR. Sequence and phylogenetic analyses were facilitated by DNASTAR, CLUSTAL V and SeqPup genetic sequence analyses programs. Of the 55 individuals, HIV env gene sequences were successfully amplified from 37 (67%). Subtype A was the predominant subtype (22/37 or 59%), while subtypes C (22%) and B (16%) were found less frequently. Recombinant env gene sequences (subtype A/G) were detected in an individual from Nigeria. The mean nucleotide sequence divergence among seven subtype B strains from Cameroon, Ethiopia, Ghana, Kenya, Nigeria and Sierra Leone, compared to the cosmopolitan HXB2 sequence in the US, was 24.3%. Phylogenetic analyses segregated subtypes A, B and C with high bootstrap values. We and others have previously demonstrated non-B HIV subtypes, including subtypes A through F, among US military personnel deployed overseas, as well as among recent immigrants and inner-city US residents with no international travel history. Jet-age travel has enormously accelerated the dissemination of HIV infection, such that multiple divergent HIV subtypes have been introduced and are spreading rapidly in developed and developing countries. Although all non-B HIV subtype-infected individuals in our cohort were detected using commercially available HIV tests, the presence of non-B HIV subtypes justifies the development of multi-subtype HIV vaccines. Additionally, research on the efficacy of currently available HAART on non-B HIV subtypes needs urgent attention. To our knowledge this is the first large cohort of non-B HIV-infected individuals found in a growing metropolitan area in the US and further underscores the importance of HIV subtype surveillance in key entry points in the US, as well as other major metropolitan areas worldwide.

Myers, R.A., Nerurkar, V.R., Woodward, C.L., Tongson, J., and Alexander, S.S.: HIV-1 subtypes A, B, C and recombinant HIV-1 (A/G) among HIV-1-infected individuals in the Baltimore-Washington metropolitan area. AIDS Research and Human Retroviruses (in preparation).