HIV infection continues to be a global health crisis. Since 1985 the blood supply has been screened for HIV with an effective test. The main way the virus is transmitted by blood products now is through the sharing of needles by persons abusing drugs. The virus can be passed in body fluids including sperm.
Oral sex can also result in transmission.
The infection can be passed from men to women, women to men, men to men, and women to women. Treating pregnant mothers with anti-HIV drugs is very effective in limiting transmission to infants, but some transmission still occurs. The risk of transmission is further diminished by Cesarean section. HIV is an infection of the immune system so it destroys the body's ability to fight off infections. It is caused by a virus, which is a microscopic organism that can only reproduce itself by entering human cells and using these to make the building blocks for new viruses.