Acquired immunodeficiency syndrome (AIDS) is a disease in which the body's natural defense system is disabled, allowing organisms that are normally fought off to become deadly.

Causes

AIDS, discovered in 1979, is caused by a microorganism called the human immunodeficiency virus (HIV). This virus is carried and transmitted in bodily fluids (mainly blood, semen, and vaginal secretions). Sexual intercourse (heterosexual or homosexual), use of nonsterile hypodermic needles (a common practice among drug addicts), and infected blood transfusions have all been implicated as a means of transmission.

Transmission from a pregnant woman to her infant or from a mother to her nursing infant may also occur. An infected physician or dentist can infect a patient if proper precautions aren't taken.

Prostitutes, people who inject drugs, and hemophiliacs who receive multiple blood transfusions for their disorder are all at high risk of developing AIDS. Heterosexual intercourse is also a common route of transmission. Having unprotected sex, whether homosexual or heterosexual, with multiple partners also puts one at high risk of being infected with HIV.

A widespread misconception has been that AIDS can be contracted by giving blood -- this is not true. In addition, since the introduction of a blood screening test for use in blood banks and hospital laboratories, acquisition of HIV by receiving blood transfusions is now extremely unlikely.

Symptoms

Clinical illness from AIDS can have its onset as long as ten years after initial infection with the virus. Initial symptoms include low-grade fever, swollen lymph nodes, weight loss, fatigue, night sweats, and persistent diarrhea. (It is important to note that these symptoms can also be present in a large number of less serious illnesses.)

Because of impairment of the immune system, people with AIDS easily fall prey to many diseases, including various types of cancer, skin infections, fungal infections, and tuberculosis. Some people with AIDS develop a previously rare cancer known as Kaposi sarcoma, which often appears as purplish bumps on the skin. Many suffer Pneumocystis carinii pneumonia (a serious and often fatal lung infection).

Diagnosis and Treatment

The blood of people with AIDS contains an abnormally small number of specialized white blood cells called lymphocytes. Lymphocytes play an important role in combating infectious diseases and may also be instrumental in destroying malignant growths in their early stages.

There are two types of lymphocytes actively engaged in coping with infection: T cells, which directly kill invaders, and B cells, which are involved in the production of infection-fighting antibodies. The finding that people with AIDS have decreased numbers of T cells, particularly a subtype called helper T cells, has proved useful in diagnosis.

A person may be a carrier of the virus without being aware of the fact and without having any of the symptoms. For this reason, blood tests for the detection of antibodies to HIV have been developed. HIV "viral load" can also be measured directly in the blood.

Newborns whose mothers are infected with the virus will initially test positive for the antibody to HIV. However, in only about half of those infants will this positive test persist after 15 to 18 months of age, and these are the infants who may eventually develop the disease.

No cure for AIDS has yet been found, but research to find one continues. "HAART" therapy (Highly Active Anti-Retroviral Therapy), a regimen of a combination of antiviral drugs, has been shown to improve quality of life and outcome in people with AIDS. In addition, infections related to AIDS can be prevented and treated with appropriate therapy.

Prevention









Since there is no cure for AIDS, prevention is critical. Limiting the number of one's sexual partners and using condoms decrease the risk of sexual exposure to the AIDS virus. Avoiding contact with potentially contaminated hypodermic needles and with blood and blood products is also important.

If a person has tested positive for the presence of the HIV antibody, there are a number of precautions that should be taken to promote the effectiveness of the immune system and to prevent the possible spread of infection.

Substances that will burden the immune system should be avoided. These include live-virus vaccines, such as those against measles, mumps, rubella, and polio; alcohol, tobacco products, and illicit drugs, such as marijuana and heroin; and possible sources of salmonella and other food-borne infections, such as unpasteurized milk and inadequately cooked meats. A physician may also recommend avoidance of immunosuppressive drugs, such as corticosteroids, some antibiotics, and certain anticancer drugs.

Among the activities that may increase risk of infections in a person with HIV infection are changing cat litter (cats transmit toxoplasmosis), cleaning bird cages (birds transmit histoplasmosis and psittacosis), sharing razor blades and toothbrushes, and engaging in sexual activity without a condom or with a partner who might transmit cytomegalovirus, Epstein-Barr virus, or syphilis. It is important that the immune system be bolstered by maintaining general health -- the person should choose a balanced diet, get regular exercise and adequate rest, and avoid stress as much as possible.

It's crucial that the infected person should inform all sex partners and medical and dental personnel with whom he or she comes into contact and should not donate blood, sperm, organs, or body tissues.