Polio refers to poliomyelitis, also known as poliomyelitis, an infectious disease caused by poliovirus infection. Poliomyelitis is generally susceptible in children under 3 years of age, and is usually transmitted through the fecal-oral route. The clinical manifestations of polio are divided into six phases: incubation, prodromal, pre-paralytic, paralytic, recovery and residual paralysis, and the general incubation period is 5-14 days, and in the prodromal period of 1-3 days there will be a low-grade fever, sore throat, coughing, diarrhea and other symptoms. In the pre-paralytic stage, the poliovirus has invaded the nervous system, and the patient may show restlessness, lethargy, excessive sweating, meningeal irritation signs, muscle pain, and skin irritation. The paralytic phase mostly occurs in the 2nd-7th day of the disease, there will be fever, muscle pain, and acute flaccid paralysis when it reaches the peak, usually there is unilateral weakness of the lower limbs, the paralysis stops progressing after the fever subsides, and the recovery period is 1-2 years, and if it still can’t be recovered as residual paralysis.