As HIV weakens the immune system it loses its ability to protect the body. Common germs that a healthy immune system can easily deal with can become serious illnesses for a person with HIV.
These illnesses are called opportunistic infections or OIs because it’s as if these germs are “taking advantage” of a run-down immune system the way a thief might take advantage of a police strike or a blackout.
There are many different opportunistic infections caused by a variety of viruses and other germs. AIDS was first noticed in the early 1980s because people were getting sick from two opportunistic infections, Pneumocystis carinii pneumonia (PCP), a lung infection, and Kaposi’s sarcoma (KS), a kind of cancer. These days, KS is less common and PCP can be prevented.
The most common opportunistic infection worldwide is tuberculosis or TB, a disease that usually infects the lungs. While TB is a serious disease, it can usually be treated. A person may have to take four or more drugs for up to a year to control the TB.
Cytomegalovirus, or CMV, is the name of a virus many people catch at some point. A healthy immune system will usually prevent CMV from causing disease, but for people with AIDS, CMV can cause serious problems, including blindness. CMV can be treated with drugs.
This is the end of the section, HIV in people. In the next section, What we can do about HIV, you’ll read about testing for HIV, anti-HIV drugs, and HIV vaccines.
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