Cause	Virus - Human immunodeficiency virus (HIV).
Distribution	Worldwide.
Transmission	Sexual - Higher risk with anal intercourse. Blood contact - For example, in people who receive contaminated blood transfusions and in drug abusers who use contaminated needles and syringes. Mother to child transmission
Incubation	3 - 10 years.
	Destruction of the bodys immune system (natural defense) leaves the body susceptible to diseases which the normal person can resist.
Symptoms	In the early stages of HIV infections, there may be a mild illness (acute HIV infection) associated with: - Fever. - Headache. - Generalised swelling of the lymph glands. - Rash. These symptoms pass off, often unnoticed and the person may feel completely well afterwards. Over the years, he begins to develop other signs of chronic HIV  infection such as: - Persistent generalised lymphadenopathy or PGL (a persistent swelling of the lymph glands). - AIDS related complex (ARC) which includes symptoms of ill health such as fever, weight loss, severe tiredness and diarrhoea plus PGL. Finally, when the immune system is near collapse, the person develops full blown AIDS which is characterised by the symptoms of the diseases to which the person  lacks resistance such as:Pneumonia (commonly caused by pneumocystis carinii).Severe diarrhoea caused by unusual organisms.Brain infections.Kaposis sarcoma, a rare skin cancer.
Diagnosis	Physical examination. Special diagnostic tests for diseases known to be associated with AIDS.
Treatment	No known cure. Antiviral drugs may prolong life and alleviate symptoms but death is inevitable.
Complications	Death. Danger also of pregnant women transmitting infection to the baby.
Comments	AIDS started in the male homosexual community but has spread to intravenous drug abusers, heterosexual men and women and children. The number of heterosexual  cases now exceed the homosexual cases, dispelling the myth  that AIDS is primarily a homosexual disease. A vaccine is not yet available. AIDs has a long  incubation period when symptoms are absent, yet the person is fully capable of spreading infection to others. In other  words, he is a carrier.