Infectious diseases are diseases caused by various pathogens that can be transmitted from person to person, from animal to animal or from animal to person. At present, three classes (Class A, Class B and Class C) of notifiable infectious diseases in 41 categories are listed in China. Also listed are those the National Health Commission has decided to include in the management of Class B and Class C diseases, and infectious diseases that are reported for emergency monitoring according to the management of Class A diseases.