What Are Opportunistic Diseases?

Opportunistic diseases are actually an entire group of diseases. By definition, an opportunistic disease is a disease that will most often make you sick given the "opportunity" of a damaged or weakened immune system (weakened because of AIDS, various forms of cancer or other causes). Because these illnesses most often appear when the immune system is damaged, they are NOT usually associated with recent HIV infection but usually occur years after infection.

Generally speaking, if you are exposed to an opportunistic disease, and you have a fully-functioning immune system, these illnesses will cause few, if any symptoms. If any symptoms are seen at all, they tend to be mild and of short duration. This is because a healthy immune system is able to successfully fight off the disease, or keep it under control.

Some diseases (like tuberculosis) can occur in anyone, regardless of their immune status, but are much more likely to cause illness and complications in persons with damaged/weakened immune systems.

Let me take this opportunity to list for you the diseases that meet the U.S. Centers for Disease Control and Prevention (CDC) surveillance definition of AIDS, when seen with documented HIV infection. You probably have never heard of most of these (let alone, are able to even pronounce them!). This is because when most people are infected with these diseases, their bodies are able to fight off the illness, often without any symptoms. Many of these are diseases that you are exposed to all of the time. If your immune system is functioning properly, the illness is fought off, or is put under control. However, if a person has a damaged/weakened immune system (from various causes), these diseases can cause symptoms or serious disease.

The following are AIDS-defining diseases (in persons with documented HIV infection):

The following are other AIDS-defining conditions, in persons with documented HIV infection:

  • CD4 cell count less than 200
  • CD4 cell count less than 14%

The following are some medical conditions that MAY indicate a problem with the immune system, but are NOT AIDS defining:

  • Candidiasis in the mouth (thrush)
  • Oral Hairy Leukoplakia
  • Microspordium in the intestines lasting for more than one month
  • Other illnesses of unusual severity or duration.

Remember, ALL of these illnesses and conditions can also be found in people with other problems of the immune system, unrelated to HIV or AIDS. Therefore being diagnosed with any of these illnesses or conditions, by themselves, does NOT specifically indicate HIV infection or AIDS. ONLY a doctor can diagnose these illnesses and conditions. None of these diseases or conditions can be diagnosed by symptoms alone. All of these must be diagnosed by laboratory tests. If a person has one of these illnesses, but does not have HIV, they do not meet the CDC surveillance definition of AIDS. Remember, there are many other medical conditions that can also cause immune system problems.

Do you want more information on HIV, AIDS, other sexually transmitted diseases or safer sex? Contact the U.S. Centers for Disease Control Health Line, open 24 hours a day, seven days a week, at 1-800-232-4636. Or visit The Body's Safe Sex and Prevention Forum.

Until next time . . . Work hard, play hard, play safe, stay sober!