Symptoms caused by opportunistic infections

Opportunistic infections are caused by germs that are around us all the time but which can normally be fought off by a healthy immune system. Once the immune system is sufficiently weakened, such infections will develop and produce any of a wide range of symptoms. Some of these symptoms can be very severe. Certain cancers also become more common when the immune system is weakened.

Such symptoms, however, cannot themselves be interpreted as definite signs of HIV infection or AIDS. A diagnosis of AIDS requires signs of severe immune deficiency, which cannot be explained by any factor except HIV. This generally requires an HIV test.