In general, AIDS symptoms develop over time, although some people may experience a flu-like illness within a month or so of being infected. As the level of CD4+ T cells in the body decreases and the immune system is weakened, symptoms progressively get worse. Opportunistic infections can cause signs and symptoms of AIDS such as shortness of breath, weight loss, and diarrhea.
The term AIDS (autoimmune deficiency syndrome) applies to the most advanced stages of HIV (human immunodeficiency virus) infection. The definition of AIDS includes all HIV-infected people who have fewer than 200 CD4+ T cells per cubic millimeter of blood. (Healthy adults usually have CD4+ T cell counts of 1,000 or more.)
The definition of AIDS also includes 26 clinical conditions that affect people with advanced HIV disease. Most of these conditions are opportunistic infections that generally do not affect healthy people. In people with AIDS, these infections are often severe, and sometimes fatal, because the immune system is so ravaged by HIV that the body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes. Common AIDS symptoms that stem from these opportunistic infections include:
- Coughing and shortness of breath
- Seizures and lack of coordination
- Difficult or painful swallowing
- Mental symptoms, such as confusion and forgetfulness
- Severe and persistent diarrhea
- Vision loss
- Nausea, abdominal (stomach) cramps, and vomiting
- Weight loss and extreme fatigue
- Severe headaches
Children with AIDS may get the same opportunistic infections as adults with the disease. In addition, they have severe forms of the typically common childhood bacterial infections, such as conjunctivitis (pink eye), ear infections, and tonsillitis.