Acute HIV infection: The body's initial reaction to infection by the HIV virus. Acute HIV infection is a flu-like syndrome that occurs immediately after a person contracts HIV (the human immunodeficiency virus 1, the agent that causes AIDS). The syndrome is characterized by fever, sore throat, headache, skin rash and swollen glands (lymphadenopathy).
This syndrome precedes seroconversion -- the development of detectable antibodies to HIV in the blood as a result of the infection. It normally takes several weeks to several months for antibodies to the virus to develop after HIV transmission. When antibodies to HIV appear in the blood, a person will test positive in the standard ELISA test for HIV.