Fever is a higher than normal body temperature.
Usually your body temperature is controlled within a narrow range near 37 degrees Centigrade or 98.6 degrees Fahrenheit by adjusting mechanisms that produce and release heat. Fever occurs in response to infections caused by viruses, bacteria, fungi, and parasites. Certain tumors, such as lymphoma , may cause fever. Rarely, HIV infection itself may produce fever, but other conditions should be excluded before this is concluded. A fever is cause for concern because it could indicate a serious infection if not identified and treated rapidly.