Human Immunodeficiency Virus (HIV) is a retrovirus which uses its RNA and the DNA of infected host cells to replicate viral DNA. Infection occurs by the transfer of blood, semen, vaginal fluid or breast milk. There are two known strains of HIV: HIV-1 and HIV-2. HIV-1 is the virus that was initially discovered and is more virulent, easily transmitted, and causes the majority of HIV infections globally. HIV-2 is less easily transmitted and is largely found in West Africa.
Infection with the HIV virus results in the progressive deterioration of the immune system leading to immunodeficiency at which point the body can no longer fulfill its role of fighting off infections and diseases. Acquired Immune Deficiency Syndrome (AIDS) applies to the most advanced stages of HIV infection, defined by the occurrence of any of more than 20 opportunistic infections or HIV-related cancers.1
According to the latest Joint United Nations Programme on HIV/AIDS (UNAIDS) AIDS epidemic update, HIV affects 33.4 million people worldwide, 2.1 million of whom are children under 15 years of age. An estimated 2.7 million people were newly infected with HIV in 2008, while 2 million succumbed to AIDS2.
The epidemic proportions of HIV and AIDS is particularly noticeable in developing countries. Even though the HIV prevalence, the number of new infections and the annual HIV-related mortality decreased in 2008 compared to the beginning of the 21st century, Sub-Saharan Africa remains the region most heavily affected by HIV. The region accounted for 67% of HIV infections worldwide, 68% of new HIV infections among adults and 91% of new HIV infections among children and for 72% of the world’s AIDS-related deaths in 2008. More than 14.1 million children in sub-Saharan Africa were estimated to have lost one or both parents to AIDS this year.2