Symptoms
There are three basic patterns of polio infection: subclinical infections, nonparalytic, and paralytic. Most people have subclinical infection, and may not have symptoms.
People with subclinical polio infection might not have symptoms, or mild symptoms may last 72 hours or less.
Clinical poliomyelitis affects the central nervous system (brain and spinal cord), and is divided into nonparalytic and paralytic forms. It may occur after recovery from a subclinical infection.