The average incubation period for people with HIV without treatment is about 9 years. During the incubation period the patient has no obvious symptoms, but the virus is already replicating in the patient’s body during the incubation period. As the virus continues to replicate and the immune system is compromised, the patient’s CD4+ T-lymphocytes will continue to decline. After entering the AIDS phase, the patient will develop various opportunistic infections secondary to the extremely low immune function. This can be manifested as fever, night sweats, diarrhea, weight loss of 10% or more for more than one month, and some patients may also develop neuropsychiatric symptoms, such as memory loss and mental apathy. In addition, generalized lymph node enlargement, pneumocystis pneumonia, cryptococcal meningitis, Candida albicans esophagitis, giant cell retinitis, etc. can occur, and eventually death can result from opportunistic infections. The average survival period of the AIDS stage is about 12-18 months.