AIDS

AIDS -- acquired immunodeficiency syndrome -- is caused by the human immunodeficiency virus (HIV). By killing or damaging cells of the body's immune system, HIV destroys the body's ability to fight infections and certain cancers. People diagnosed with AIDS may get life-threatening diseases called opportunistic infections, which are caused by microbes such as viruses or bacteria that usually do not make healthy people sick.

How HIV Spreads
HIV is spread most commonly by having sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.

HIV also is spread through contact with infected blood. Today, because of blood screening and heat treatment, the risk of getting HIV from such transfusions is extremely small.

HIV frequently is spread among injection drug users by the sharing of needles or syringes.

Women can transmit HIV to their babies during pregnancy, birth, or breast feeding.

Although researchers have detected HIV in the saliva of infected individuals, no evidence exists that the virus is spread by contact with saliva. Scientists also have found no evidence that HIV is spread through sweat, tears, urine, or feces.

Studies of families of HIV-infected people have shown clearly that HIV is not spread through casual contact such as the sharing of food utensils, swimming pools, or toilet seats.

HIV can infect anyone who practices risky behaviors such as:

• sharing drug needles or syringes, or
• having sexual contact with an infected person without using a condom or with someone whose HIV status is unknown.

Having a sexually transmitted disease such as syphilis, genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis appears to make people more susceptible to acquiring HIV infection during sex with infected partners.

Early Symptoms
Many people do not develop any symptoms when they first become infected with HIV. Some people, however, have a flu-like illness within a month or two after exposure to the virus. This illness may include fever, headache, tiredness, and enlarged lymph nodes (organs of the immune system easily felt in the neck and groin). These symptoms usually disappear within a week to a month and are often mistaken for those of another viral infection. During this period, people are very infectious, and HIV is present in large quantities in genital fluids.

More persistent or severe symptoms may not surface for a decade or more after HIV first enters the body in adults, or within two years in children born with HIV infection. Some people may begin to have symptoms as soon as a few months, while others may be symptom-free for more than 10 years. During this time, however, the virus is actively multiplying, infecting, and killing cells of the immune system.

As the immune system is attacked, complications start to take over. Symptoms often experienced months to years before the onset of AIDS include:

• large lymph nodes or "swollen glands,"
• lack of energy,
• weight loss,
• frequent fevers and sweats,
• persistent or frequent yeast infections (oral or vaginal),
• persistent skin rashes or flaky skin,
• pelvic inflammatory disease in women that does not respond to treatment, or
• short-term memory loss.

Some people develop frequent and severe herpes infections that cause mouth, genital, or anal sores, or a painful nerve disease called shingles. Children may grow slowly or be sick a lot.

AIDS
When the number of infection fighting cells (called CD4+ T cells or T4 cells) in an HIV-infected person reach a very low level, the disease is called AIDS. People with AIDS have a greater risk of opportunistic infections, which rarely cause harm in healthy people. These infections may cause symptoms such as coughing and shortness of breath, seizures and lack of coordination, difficult or painful swallowing, mental symptoms such as confusion and forgetfulnesss, severe and persistent diarrhea, fever, vision loss, nausea, abdominal cramps, and vomiting, weight loss and extreme fatigue, severe headaches, and coma.

People with AIDS can also develop various cancers, especially those caused by viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune system known as lymphomas.

Last Updated: December 03, 2007