While some people experience a mild flulike illness within two to four weeks of exposure to the virus, it generally takes at least two to five years before any symptoms of HIV infection appear. In many cases, the first symptoms are nonspecific and variable. One of the most common is a tongue that is coated with white bumps. This is oral thrush, or candidiasis. Candidiasis indicates a compromised immune system.
Intestinal parasites are another common problem.
The medical criteria for a diagnosis of full-blown AIDS are quite specific, requiring the presence of one or more opportunistic infections or cancers known to be associated with HIV infection. Rather, it means that one has been exposed to HIV, as demonstrated by the presence in the blood of antibodies to the virus. Some authorities believe that, although strongly linked to HIV, AIDS must be considered a disease caused by many factors. Conversely, some people with signs of full-blown generalized immune deficiency, consistent with a diagnosis of AIDS, actually test negative for HIV antibodies. This is probably due in part to the dis-ease's long incubation period, but there are some people who have tested positive for HIV for many years and have never developed any symptoms of immune deficiency.