Like all viruses, HIV depends on the cells of its ‘host’ to multiply. HIV uses CD4 cells: a type of white blood cells, which are part of the host’s immune system. The HIV virus first penetrates into the CD4 cell. Inside the cell, the genetic material of the virus is inserted into the DNA of the CD4 cell. When the DNA of the host cell is copied, the viral material is copied simultaneously. In this step, HIV needs a specific enzyme, reverse transcriptase. These HIV proteins are secreted as long-chain-molecules, which are then cut to pieces by another enzyme, protease. The resulting small protein particles are reassembled to form new, virulent copies of the original virus; they spread out to infect new host cells and repeat this multiplication cycle over and over again.
HIV TransmissionHIV is transmitted through body fluids, in particular blood, semen, vaginal secretions and breast milk. There are 3 different ways of transmitting HIV:
- Unprotected sexual contact with an infected partner
- Blood contact through infected blood transfusions, sharing contaminated injection needles (drug addicts)
- From infected mother to child during pregnancy, birth or breastfeeding