Signs and symptoms of Primary HIV infection generally occur days to weeks after infection, during which there are high levels of replicating virus and an attempt by the host immune system to control virus. Primary infection is often under diagnosed. The patient typically presents with a flu-like illness of non-specific signs and symptoms. Common symptoms include fever, fatigue, pharyngitis, myalgia, rash and lymphadenopathy. Some other symptoms may include headache, gastrointestinal symptoms, night sweats, weight loss, oral ulcers, oral thrush and aseptic meningitis.