Molecular epidemiology of HIV

The acquired immunodeficiency syndrome (AIDS) continues to spread unchecked since its first documentation in 1981. Two decades later, nearly 50 million individuals are living with HIV/AIDS world wide, according to figures released by the Joint United Nations Program on HIV/AIDS (UNAIDS) and the World Health Organization (WHO)1. There are two types of human immunodeficiency virus (HIV) responsible for this infection/disease. A major proportion of the infection worldwide is caused by the HIV-1 virus, which was identified in 19832,3. The type 2 (HIV-2) virus was first detected in West Africa and is significantly prevalent in those regions, Portugal and India with rare cases reported from western countries, Korea and Philippines4-10. Since, the commencement of the AIDS epidemic two decades ago, HIV-1 has evolved, differing from one geographical location to another11. This variability at the genomic level can be attributed to high mismatch error rate of the HIV reverse transcriptase (RT) enzyme coupled with the absence of proof reading capacity, diploid genome, the rapid turnover of the virus in vivo, viral fitness, immune response o