Stage 1 primary infection
Entry of HIV-1 or HIV-2 through a mucosal surface after sexual contact, direct inoculation into the bloodstream by contaminated blood products, or IV drug abuse can be followed by a transient febrile illness up to 6 weeks later associated with oral ulceration, pharyngitis, and lym-phadenopathy. Photophobia, meningism, myalgia, prostration, encephalopathy and meningitis may also occur. FBC may show lym-phopenia or lymphocytosis often with atypical lymphocytes, neutropenia, thrombocytopenia or pancytopenia. Major differential diagnoses are acute viral meningitis and infectious mononucleosis. False +ve IM serology may occur. Specific IgM then IgG antibody to HIV appears 4-12 weeks after infection and routine tests for HIV may be -ve for up to 3 months. However, the virus is detectable in plasma and CSF from infected individuals during this period and the patient is highly infectious.