Enterovirus EV71 is a type of human enterovirus, abbreviated as EV71, which often causes hand, foot and mouth disease, viral pharyngitis in children, and can appear as pulmonary edema and encephalitis in severely ill children, collectively referred to as enterovirus EV71 infection diseases. Infants and children under three years of age are more likely to be infected, and adults can also be infected. Poor environmental hygiene, food hygiene, and poor personal hygiene habits predispose to the disease. Most cases are mild and can be cured. A few patients may develop encephalitis and encephalomyelitis, pulmonary edema, circulatory failure, etc., which can be life-threatening in severe cases. Morbidity characteristics: the age group is generally small, the oldest patient is 11 years old, the youngest is only about 1 year old, of which 2-3 years old is the majority; secondly, the onset of the area is scattered, and mainly in rural areas.