Understanding HIV/AIDS -- the Basics
What Causes HIV/AIDS?
HIV lives in human blood and sexual fluids (semen and vaginal secretions). The infection is spread from person to person when these body fluids are shared, usually during vaginal or anal sexual contact or when sharing injectable drugs. It can also be passed from dirty needles used for tattoos and body piercing. HIV does not live in saliva, tears, urine, or perspiration -- so HIV cannot be spread by casual contact with these body fluids. It can be spread through oral sex, although the risk is small.
HIV cannot survive for long outside the human body and dies quickly when the body fluid in which it is contained dries up. It is not spread by animals or insects and is not found on public surfaces. It's actually not as easy to get as other infectious diseases.
A mother can pass HIV to her child during birth when the child is exposed to the mother's infected blood. Breastfeeding does carry a risk for HIV infection, though in some areas of the developing world, breastfeeding is considered safer than feeding a newborn contaminated water.
There are two main types of HIV, called HIV-1 and HIV-2. HIV-2 is rarely found outside Africa and parts of Asia, so there is no need to test for it specifically -- unless a person has had contact with someone from an area of the world where HIV-2 is common.
Blood transfusions were once a concern, but all blood products used in the United States today are tested for several infectious diseases, including HIV. If signs of disease or other problems are found in donated blood, the person who donated the blood is notified to be re-tested by their health care provider and is not permitted to continue donating blood. Any donated blood that tests positive for HIV is disposed of and never makes it into the public blood supply.