HIV, the human immunodeficiency virus, causes the final symptoms of the disease process of AIDS, acquired immunodeficiency disease syndrome. HIV and AIDS are two of the most difficult disease processes to treat, because the disease infects and breaks down a person's immunity, causing problems within every system of the body, according to the U.S. Centers of Disease Control and Prevention. The HIV virus causes the end-stage disease, AIDS, of the virus.
Body Fluids
Transmission of the HIV virus, which causes AIDS, can infect a person who participates in unprotected sexual intercourse or other sexual activities, the U.S. Centers of Disease Control and Prevention says. The virus is transmitted within female vaginal fluids and male semen. Breast milk from an infected mother also contains the virus.
Needle Sharing
Sharing needles during illicit drug use can also transmit the HIV virus, according to the U.S. Centers of Disease Control and Prevention. The virus remains on the needle and transmits the virus via the blood on the needle. The person may not notice tiny amounts of blood on the needle.
Blood Transfusions
Blood transfusions prior to 1985 in the United States were not tested as thoroughly as today. If a person received blood prior to 1985, or while in another country without stringent screening practices, he may have received infected blood. Because AIDS does not appear for many years after exposure to the virus, the person may not know he has it for a long time. According to MayoClinic.com, careful blood screening practices at hospitals now make transmission via transfusion very unlikely.
Birth
The HIV virus passes through the placenta to the fetus during pregnancy, and the baby may become infected. There is no sure way to protect the fetus from a mother infected with HIV, according to the U.S. Centers of Disease Control and Prevention.
Multiple Sex Partners
Having multiple sex partners places a person at risk for HIV. Using condoms can reduce the risk but cannot assure 100 percent protection against the HIV virus that causes AIDS. Birth control pills offer no protection against AIDS.
