The first reported cases of AIDS were back in 1981 in the USA. Doctors had come across a rare set of symptoms which included: pneumonia (caused by a parasite called Pneumocystis carinni), cytomegalovirus infections, thrush and Karposi’s sarcoma (a rare form of skin cancer). The patients that were suffering with these symptoms were all young homosexual men with limited immune systems.
Soon after this over in central Africa doctors were treating patients with a new disease that also undermined the immune system and caused diarrhoea and weight loss, namely “slims disease”, however these patients were all heterosexual. The causes and modes of transmission were not yet known. In 1983 it was discovered that this disease was caused by a virus, known to be LAV (lymphadenopathy – associated virus) and HTLV – III (human T cell lymphotropic virus type III). In May 1986 the virus was renamed HIV (human immunodeficiency virus).
Two viruses are now associated with AIDS: HIV – 1 and HIV -2.
HIV-1 is associated with infections in Central, East and southern Africa, North and South America, Europe and the rest of the world.
HIV-2 was discovered in West Africa (Cape Verde Islands, Guinea-Bissau and Senegal) in 1986 and it is mostly restricted to West Africa.
HIV-2 is similar to HIV-1, but HIV-2 is less pathogenic than HIV-1, and HIV-2 infections have a longer latency period with slower progression to disease, lower viral counts and lower rates of transmission.
