Clinical stages of HIV infection

The American health authority CDC (Center for Disease Control and Prevention) defines 3 clinical stages of the disease and 3 immunological categories. According to the CDC definition HIV can only be diagnosed with a confirmed HIV positive test.

Stage A covers both the acute HIV illness and the subsequent clinical latency.The acute HIV illness arises 3-6 weeks after infection for 50-70% with flu type symptoms: fever, skin eruptions, throat inflammation, muscular pains, lymph node swelling, headache, and nausea.
During clinical latency there are no further complaints although some people have continuous Lymphadenopathie in the shoulders, back or neck. The clinical latency can last for many years.

Stage B consists of disease symptoms prior to stage C (AIDS), which further weakens the immune system. Usually these symptoms accompany a general worsening of health. In addition to long lasting (a month plus) symptoms such as fever, night sweats and weight loss, many other infections such as candida infections of the mouth and throat or viral illnesses like belt rose occur.

Stage C is the final phase of the HIV infection, the actual AIDS illness. It is the collapse of the immune system. The pattern of the AIDS illness is unmistakable although individual symptoms may vary. Diverse infections and cancers are common, as are fungal infections of the esophagus and special forms of pneumonia (Pneumocystis carinii Pneumonia), also common are virus illnesses (i.e. retinal inflammation CMV-Retinitis), parasite infection (i.e. Toxoplasmosis that causes brain abscesses), rare cancer forms (e.g. Kaposisarkom, Lymphdrüsensarkom, brain tumors) as well as neurological illnesses (among other things HIV dementia) and strong weight loss (Wasting syndrome).



The defense system defends against the HIV infection (blue curve). But the HIVs (red curve) attack, infiltrate, and destroy them. During the first weeks the human defense system wins the first battle (decrease of the viruses), but eventually the HIVs overwhelm the immune system and the infected person dies. The concentration of the CD4+ helper cells is a good indicator of the condition of the human defense system, and is used nowadays as a measure of HIV infections.