HIV virus is transmitted through sexual contact, exposure to blood or blood products or perinatally from mother to foetus. Antenatal screening and screening of blood products for HIV has significantly reduced the risk of transmission in blood transfusion and pregnancy. The incubation period is an average of two to four weeks but may be up to several months. A variety of non-specific symptoms including fever, myalgia, sore throat, rash, lymphadenopathy, weight loss, mucocutaneous ulcers and diarrhoea, are associated with acute infection however up to 60% of early infection may be asymptomatic. Antiretroviral therapies are very effective at controlling virus replication and preventing onward transmission of infection and progression to AIDS for those infected.