Brief History - Began as a new disease in West Africa, spread to Europe and USA in the 70's where it began to be evident in the early 80's. Blood test to make the diagnosis was developed in 1983. Virus infects the DNA of the host, and uses host DNA to reproduce. Viral particles infect and kill cells important to our immune function, among others - Helper T cells and macrophages. Symptoms may take years to develop, and relate to diminished immune function, e.g. thrush, herpes, warts, certain cancers, opportunistic infections.
All people are at risk.
Sexual transmission is most common, then IVDU, but accidental needle sticks can occur, and maternal-fetal transmission is common. Gays and IVDU's remain a high risk group, and minority women are another emerging risk group. How to prevent - safe or no sex. Antivirals for pregnant women. Breast feeding is a risk.