Acquired Immune Deficiency Syndrome (AIDS) is caused by one of two viruses: HIV-1 or HIV-2.
HIV-1 is the predominant virus in most parts of the world, including South Africa, while HIV-2 is most commonly found in West Africa.
The two HI viruses are retroviruses that insert their genetic material into the DNA of the cells of the person they’ve infected. In this way, they can infect you for the rest of your life, while decreasing your resistance to infections and certain cancers.
The HI virus, which is circular in shape, does something that no other virus does: it attacks your CD4 cells (the most important immune cells in your body), uses them to reproduce, and then destroys them.
The immune system weakens as more CD4 cells are killed, eventually progressing to AIDS.
The choice of antiretroviral treatment (ART) for HIV-2 differs from that for HIV-1, which is why it’s important to get tested properly. ART is designed to interfere with the virus’s ability to reproduce, slowing down the progression of HIV to AIDS.
Reviewed by Dr Pooja Balani, MBBS (UK). Medical Technical Advisor at the Southern African HIV Clinicians Society. March 2018.