In our bodies, we carry many germs. They ooccur in many varieties, including. bacteria, protozoa, fungi, and viruses. When our immune system is working, it controls these germs. But, when the immune system is weakened by HIV disease, cancer, serious illness or by some medications, these germs can get out of control and cause health problems. Infections that take advantage of weakness in the immune defenses are called "opportunistic". You can be infected with an OI, and "test positive" for it, even though you don't have the disease. You may be asymptomatic. For example, almost everyone with HIV tests positive for Cytomegalovirus (CMV). But it is very rare for CMV disease to develop unless the T-cell count drops below 50, a sign of serious damage to the immune system. To see if you're infected with an OI, your blood might be tested for antigens (pieces of the germ that causes the OI) or for antibodies (proteins made by the immune system to fight the antigens). If either the antigens or the antibodies are found, it means you're infected. If you are infected with a germ that causes an OI, and if your T-cells are low enough to allow that OI to develop, your doctor will look for signs of active disease. These are different for the different OIs.
Causes of Opportunistic Infection
People who aren't HIV-infected can develop OIs if their immune systems are damaged. For example, many drugs used to treat cancer suppress the immune system. Some people who get cancer treatments can develop OIs. HIV weakens the immune system so that opportunistic infections can develop. If you are HIV-infected and develop opportunistic infections, you might have AIDS. In the US, the Center for Disease Control (CDC) is responsible for deciding who has AIDS. The CDC has developed a list of about 24 opportunistic infections. If you have HIV and one or more of these "official" OIs, then you have AIDS. In the early years of the AIDS epidemic, OIs caused a lot of sickness and deaths. Once people started taking combination antiviral therapy, however, a lot fewer people got OIs. It's not clear how many people with HIV will get a specific OI. The most common OIs are listed here along with the disease they usually cause: 1. Candidiasis (Thrush) is a fungal infection of the mouth, throat, or vagina. 2. Cytomegalovirus (CMV)is a viral infection that causes eye disease that can lead to blindness.
3. Herpes simplex viruses can cause oral herpes (cold sores) or genital herpes. These are fairly common infections, but if you have HIV, the outbreaks can be much more frequent and more severe. 4. Mycobacterium avium complex (MAC or MAI)is a bacterial infection that can cause recurring fevers, general sick feelings, problems with digestion, and serious weight loss. 5. Pneumocystis carinii pneumonia (PCP)is a protozoal infection that can cause a fatal pneumonia.
6. Toxoplasmosis (Toxo)is a protozoal infection of the brain.
7. Tuberculosis (TB)is a bacterial infection that attacks the lungs, and can cause meningitis. Everyone with HIV who tests positive for exposure to TB should be treated.
Signs and Symptoms of Opportunistic Infection
Find more information
Medical Content Last Updated on 07/12/2008
The information contained on this site is for the sole purpose of
being informative. This information is not and should not be used or relied upon as medical
advice. Always seek the advice of your physician, nurse
Or other qualified health care provider before you undergo any treatment or
for answers to any questions you may have regarding a medical condition.
If you believe you have a medical emergency, please discontinue use
of MyElectronicMD and call 911 now.
Nothing contained on or provided through the service is intended to be or is
to be used for medical diagnosis or treatment.
Your use of this site is subject to certain terms and conditions.