AIDS is an acronym for acquired immune deficiency syndrome, a disease caused by the human immunodeficiency virus (HIV). This virus attacks the immune system, the body’s line of defense against disease and infections. When the immune system breaks down, one become susceptible to serious, often deadly infections and cancers called opportunistic infections, so named because they take advantage of the body’s weakened defenses.
Soon after infection, some people develop short-term flu-like symptoms. But infected people usually show no other symptoms until the disease progresses. Patients with advancing disease can develop swollen lymph nodes, weight loss, fatigue, diarrhea, anemia and thrush, as well as various opportunistic infections, such as Pneumocystis pneumonia.
HIV is spread by sexual contact with an infected person, by needle-sharing among injection drug users or through transfusions with infected blood. HIV-infected women can transmit the virus to their newborns before or during birth, or through breast-feeding after birth. Health-care workers can become infected with HIV after being stuck with HIV-tainted needles.
People can protect themselves by not engaging in unprotected sex with those who have HIV or whose HIV status is unknown. The gold standard in sexual protection is abstinence, or the male latex condom. When used correctly and consistently, male condoms are 98 to 100 percent effective against infection, studies show. Protection is also important during oral sex, either with a male condom or dental dam, which covers the vagina. People who use injection drugs should use a clean needle each time they inject drugs. Anti-HIV therapy for pregnant women infected with the virus can reduce the risk of mother-to-infant transmission substantially.