(I) Clinical diagnosis of the case Acute onset, fever, maculopapular and herpetic rash on the palms of the hands or feet, and a rash on the buttocks or knees. The rash is surrounded by an inflammatory redness with little fluid in the blisters; scattered herpes appear in the oral mucosa and are painful. Some children may have cough, runny nose, loss of appetite, nausea, vomiting and headache. Severe cases: 1. Patients with clinical manifestations of HFMD, accompanied by myoclonus, or encephalitis, acute delayed paralysis, cardiopulmonary failure, pulmonary edema, etc. 2, infants and children in HFMD endemic areas do not have the typical manifestations of HFMD, but have fever with myoclonus, or encephalitis, acute delayed paralysis, cardiopulmonary failure, pulmonary edema, etc. (B) Laboratory diagnostic cases Clinical diagnostic cases meet one of the following conditions, that is, laboratory diagnostic cases 1, virus isolation from throat swabs or throat washings, stool or anal swabs, cerebrospinal fluid or herpes fluid, and brain, lung, spleen, lymph nodes and other tissue specimens. Enterovirus is isolated from tissue specimens such as brain, lung, spleen and lymph nodes. 2.Serology test The patient’s serum is positive for specific IgM antibodies, or there is a 4-fold or more increase in serum IgG antibodies during the acute and recovery periods. 3.Nucleic acid test Pathogenic nucleic acid can be detected in the patient’s serum, cerebrospinal fluid, throat swab or throat wash, stool or anal swab, cerebrospinal fluid or herpes fluid, and tissue specimens such as brain, lung, spleen and lymph nodes.