Definition

Polio (pronounced POH-lee-oh) is a serious disease caused by a virus called the poliovirus. The full medical name for the disease is poliomyelitis (pronounced POH-lee-oh-mi-uh-LI-tis). In its severest form, polio causes paralysis of the muscles of the legs, arms, and respiratory (breathing) system.

Description

The poliovirus causes most of its infections in the summer and fall. At one time, summer epidemics of polio were common and greatly feared.

The poliovirus primarily affects younger children. But it can also infect older children and adults. Poor hygiene and crowded living conditions encourage the spread of the poliovirus.

Paralysis is the most serious symptom of polio. Only about 1 percent to 2 percent of those infected with the virus are paralyzed, however. Risk factors for paralysis include older age, pregnancy, problems with the immune system, a recent tonsillectomy, and a recent episode of very strenuous exercise.

Causes

Poliovirus is transmitted through saliva...