Infectious diseases transmitted through blood include AIDS, syphilis, viral hepatitis B, viral hepatitis C, etc. Viruses can be transmitted through sharing syringes, or through sharing personal items such as toothbrushes, nail clippers, razors, shavers, etc., and through broken skin. There is also a risk of transmission through the application of medical devices that are not strictly sterilized for invasive examinations and treatments in unregulated medical institutions, or through unauthorized blood transfusions and misuse of blood products in unregulated medical institutions. In addition, these diseases can also be transmitted through sexual intercourse, especially syphilis and AIDS, which are the most prevalent diseases transmitted through sexual intercourse.