AIDS mainly attacks the body’s T-lymphocytes, which are important immune cells that protect against a variety of pathogens. As the AIDS virus continues to replicate in the body, it continues to attack the body’s T-lymphocytes, causing damage to the immune system. When the CD4 lymphocyte count drops to less than 200/mm^3, the patient is susceptible to a variety of infections, and often enters the AIDS stage, where the patient is basically defenseless against external pathogens. Any kind of bacteria, fungus or virus can cause the infection, so its manifestations are very varied, mainly fever, night sweats, diarrhea and weight loss of more than 10% for more than 1 month, and malignant lymphoma or Kaposi’s sarcoma can appear, which can eventually lead to death.