The signs and symptoms of HIV infection and AIDS vary depending on the genetic background and age of the individual, and whether he or she has access to medical treatment.

Most HIV-positive individuals experience a sharp reduction in immune system responses, which increases vulnerability to an array of bacteria, viruses, parasites, and fungi. This vulnerability can result in “opportunistic” infections, or infections that do not normally occur in individuals with healthy immune systems.

The early stages of HIV infection are sometimes symptom-free, but most patients experience flu-like symptoms such as fevers, rashes, and sore throats as early as two weeks after contracting the virus. Since these symptoms are shared by many other viral infections, HIV infection must be diagnosed using an HIV test (see “Diagnosis“).

After the initial “acute” stage of infection, there are often no symptoms for many years. Eventually, however, development of the disease causes gradual loss of immune function as the virus kills CD4 cells (“helper T-cells”), which play a vital role in a healthy immune system. This leads to an increase in infections, with symptoms such as mucocutaneous (mucous and skin-related) lesions, upper respiratory and severe bacterial infections, chronic diarrhea, and tuberculosis.

In the advanced stages of AIDS, individuals no longer have a functioning immune system and often develop opportunistic infections and cancers that would be kept in check by a normal immune system. Symptoms of these diseases can include ulcers and small blisters from a variety of viruses, oral or vaginal yeast infections, shingles, pneumonia, non-Hodgkin’s lymphoma (cancer of the lymph glands), and Kaposi’s sarcoma (cancerous lesions on the skin, lungs, and bowel region).

The following are common illnesses in advanced AIDS patients:

• Pneumocystis carinii pneumonia (PCP pneumonia) or Pneumocystis jiroveci pneumonia (a form of pneumonia caused by a yeast-like fungus)
• Cryptococcal meningitis (an infection of the lining of the spinal cord and brain)
• AIDS dementia complex (causes the enlargement of the brain and affects cognitive functions)
• Toxoplasmosis encephalitis (causes lesions and hemorrhaging of the brain)
• Progressive multifocal leukoencephalopathy (a viral disease that causes inflammation of the brain)
• Mycobacterium avium complex (includes bacterial infections that have similar symptoms to tuberculosis)
• Cytomegalovirus infection (viruses with infections similar to herpes)

These infections and disorders affect virtually all organs in the body, including the brain and digestive organs. Extreme diarrhea and “wasting syndrome,” or severe weight loss, make it harder to absorb nutrients and perform daily functions, eventually leading to death.

Although there is no cure for AIDS or HIV infection, progression of the disease can be slowed greatly by treatment (see “Treatment Overview“), which can extend lifetimes by decades and significantly improve quality of life.

Also, while rare, some people do not experience HIV or AIDS symptoms and do not fall ill or die from the virus. Scientists have discovered that a particular mutation that affects the function of T cells, CCR5-Δ32, allows HIV-positive individuals to carry the virus without the symptoms or illness associated with AIDS.

Researchers continue to study the CCR5-Δ32 mutation in an effort to limit the symptoms and form treatments for the disease.

Diagnosis »