HIV is difficult to detect directly from the outside. AIDS is a clinically common sexually transmitted disease caused by HIV infection. It is very different from other STDs in that HIV infection causes a breakdown of the body’s immune cells. There is a long period of asymptomatic HIV infection before the onset of AIDS, during which the patient does not have any clinical manifestations, so this is very different from ordinary STDs. With common STDs such as warts, gonorrhea, or genital herpes, the patient will have typical clinical features in the genital area, such as prominent abnormalities in the genital area, so the patient will be able to detect them in time. In contrast, AIDS is difficult to detect by appearance and can only be diagnosed through blood tests.