Clinical features

AIDS infection has Four stages in the natural history.Please refer to Appendix B for details of the WHO clinical staging system.Progression of AIDS disease can be summarized as follows：

acute/primary HIV infection（or seroconversion illness）：up to 50% of patients have an apparent non-specific viral illness syndrome within 2～4 weeks post infection.

（1）WHO Clinical Stage 1：no symptoms，persistent generalized lymphadenopathy（PGL），there is a variable duration for 2～10 years.(https://www.daowen.com)

（2）WHO Clinical Stage 2：mild immune-suppression，constitutional symptoms such as weight loss，fevers and muco-cutaneous infection.

（3）WHO Clinical Stage 3：advanced immune-suppression，frequent or severe bacterial infections，chronic fever or diarrhea，significant weight loss，oral thrush.

（4）WHO Clinical Stage 4：severe immune-suppression，the stage of AIDS with opportunistic infections，malignancies and late direct effects of HIV such as encephalopathy and nephropathy.