AIDS is actually the fourth stage of HIV infection, and occurs when T cell levels in someone with HIV fall below 200. The other stages of HIV infection, in order, are: the incubation period, acute infection, and the latency period. Symptoms during each stage are different, and are used in conjunction with T cell counts to identify the separate stages of infection.

Symptoms during some stages of HIV infection can be easily mistaken for other diseases, like the flu or common cold. At some points, the infection does not have any symptoms. These two factors, and the prolonged progression of HIV infection, contribute significantly to the lethality of HIV, because people can go a long time without knowing that they have HIV. During this time, they may put others at risk of contracting the disease and do not benefit themselves from early treatment.

Incubation period symptoms

HIV does not show symptoms during the incubation period, which typically lasts between two weeks and one month.

Acute infection symptoms

This stage is typically around one month in duration and is characterized by symptoms such as:

  • high fever
  • sore throat
  • profuse sweating
  • swollen lymph nodes
  • headache
  • persistent, unexplained fatigue and lethargy
  • muscle pain
  • rashes
  • mouth sores

As noted above, the HIV infection during this stage can be mistaken for some other less serious disease because the symptoms can be similar in their outward appearance to the flu or a severe cold.

Latency period symptoms

The latency period of HIV infection begins as the acute infection symptoms subside, and can last anywhere from a couple of weeks to a couple of decades (before the onset of full-blown AIDS). While the length of the latency period and whether any symptoms appear during this state varies widely between individuals, it is not unusual for no apparent symptoms to arise during the latency period. Symptoms that do appear during this stage of HIV infection are those associated with opportunistic infections, listed below.

AIDS infection symptoms

AIDS is the fourth and final stage of HIV infection and can be less than a year to several years in length depending on whether a person receives anti-retroviral treatment and other lifestyle factors. The symptoms of AIDS are a CD4+ T cell count of less than 200 and/or the appearance of symptoms of opportunistic infections.

AIDS is characterized by opportunistic infections: it is the point in HIV infection at which the immune system is so thoroughly compromised that it cannot fight off other diseases (including those which would not be so problematic to a healthy immune system). As HIV infection progress to AIDS, more generalized symptoms often associated with opportunistic infections may appear, such as:

  • high and frequent fever, chills
  • profuse sweating, soaking night sweats
  • severe and persistent headaches
  • nausea
  • chronic diarrhea
  • extreme lethargy and fatigue
  • memory and other neurological problems, including seizures
  • blurred and distorted vision and/or vision loss
  • drastic weight loss
  • dry cough
  • shortness of breath
  • pneumonia
  • difficulty with chewing and swallowing
  • discoloration of skin and mucous membranes
  • rashes and dry flaky skin
  • mouth and throat sores
  • recurring oral and vaginal yeast infections
  • in women, untreatable pelvic inflammatory disease

People with HIV/AIDS are particularly susceptible to several types of cancer. Combined with the severity of opportunistic infections, people with HIV/AIDS can be debilitated to the point where they are unable to perform basic daily life activities.