Category B infectious diseases are those that require strict management. There are 26 Category B infectious diseases, including atypical pneumonia, viral hepatitis, AIDS, measles, typhoid fever, epidemic hemorrhagic fever, epidemic encephalitis B, whooping cough, scarlet fever and tuberculosis. If such infectious diseases are detected, direct network reporting is required within 6h of detection in towns and 12h in rural areas. There are three major categories of infectious diseases: Category A, Category B and Category C. In addition to Category B infectious diseases, Category A infectious diseases mainly refer to plague and cholera, which are potent infectious diseases under mandatory management, and are required to be reported online within 2h after discovery in cities and towns, and within no more than 6h if found in rural areas. In addition, there are 12 infectious diseases of category C, including influenza, mumps, rubella and leprosy, which are required to be reported within 24 hours of discovery.