What are the symptoms and signs of polio?
Polioviruses cause the disease “poliomyelitis” when they spread from the gut to the central nervous system (brain and spinal cord). At least 80 to 90% of cases of infection with the polio virus result in a minor illness. These are usually in young children and the illness is mild, with a sore throat, slight fever, malaise, headache and vomiting which develops three to five days after exposure to the virus. The child recovers within 24 to 72 hours. The major illness may follow several days of appearing to be well after a minor illness. However, it often occurs with no signs of previous illness at all, particularly in older children and adults. The incubation period is seven to 14 days. The first sign is often fever, followed by a severe headache and a stiff neck. This is in fact a form of meningitis, and is called an aseptic meningitis because it is not caused by a bacteria. There may also be muscle and back pain or muscle spasms and sometimes increased sensitivity to pain when the skin
