Diversity of Human Immunodeficiency Virus Type-1 Subtypes in Western Kenya

Background: HIV/AIDS is the principal pandemic in the world today. Two viral types (HIV-1 and HIV-2), with numerous groups (M, N and O for HIV-1 and A through H for HIV-2) have emerged. These have further proliferated into numerous subtypes, sub-subtypes and circulating recombinant forms (CRF) over the last 30 years. HIV-1 variants circulate together within a geographical region providing an opportunity for recombination of viral strains within infected individuals. In Kenya, at least nine different genetic HIV-1 subtypes and several recombinant forms have been defined within group M, which accounts for the majority of cases in the AIDS pandemic. Objective: To determine the genetic diversity of HIV-1 in the western region of Kenya bordering Uganda. Methodology: A cross sectional study was carried out at Busia District Hospital between 2007 and 2009. A total of 75 patients were sampled randomly from a cohort of 1000 clients on antiretroviral therapy. Blood samples were analysed at the HIV Laboratory, Kenya Medical Research Institute, Nairobi, Kenya. PCR was carried out on the Pol region of HIV, sequenced and analysed by BLAST for subtypes. Results: BLAST analysis revealed the following circulating subtypes: 40/75 (53.30%) were HIV-1 group M subtype A1; 21/75 (28.0%) were subtype D; 5/75 (6.7%) were subtype G; 4/75 (5.30%) were subtype C; and 2/75 (2.70%) were subtype A2. Only one isolate was identified for the other subtypes viz: 1/75 (1.30%) resembled subtype B; 1/75 (1.30%) was A1/C, and 1/75 (1.30%) was A1/D. Conclusion: The study showed increasing HIV-1 diversity along the Kenya-Uganda border with the emergence of A1/C and A1/D recombinants. Such HIV-1 diversityvis a vis the recent expanded access to antiretroviral therapy in resource limited settings calls for continuous evaluation of anti-HIV regimens. There is need therefore, for regular surveillance and monitoring for mutations that are likely to lead to drug resistance if we have to achieve successful treatment outcomes.