opportunistic infection

opportunistic infection An infection that is not typically seen in healthy people, but occurs because a person’s immune system is weakened. Opportunistic infections are a particular danger for people with immunodeficiency, such as AIDS, or for those receiving immunosuppressive drugs such as chemotherapy for cancer. The HIV virus itself does not cause death, but the opportunistic infections that occur because of the effect of the virus on the immune system can be lethal. See also opportunistic condition; opportunistic microorganism.