The only source of HIV infection is the person infected with HIV, and to be more specific, one needs to know the transmission routes. It is usually transmitted through blood, sexual or mother-to-child transmission. The vectors of transmission are all body fluids that contain a high amount of HIV in the body of the AIDS patient. If it is saliva or sweat, it will not lead to the transmission of AIDS because the HIV content is relatively low. Only the blood, reproductive tract secretions, breast milk, chest and abdominal water of AIDS patients without regular antiretroviral treatment can contain a large amount of HIV in a relatively high concentration. Therefore, in this case, it is possible to contact other people’s wounds or broken mucous membranes through these body fluids, thus leading to transmission, while other cases will not lead to transmission.