Polio (infantile paralysis) is a communicable disease, which is categorized as a disease of civilization. Polio spreads through human-to-human contact, usually entering the body through the mouth due to faecally contaminated water or food.

The disease is usually fatal if the nerve cells in the brain are attacked (bulbar poliomyelitis), causing paralysis of essential muscles, such as those controlling swallowing, heartbeat, and respiration.

There is no specific drug for treatment. For reasons not clearly understood, some people who have had severe polio experience post polio syndrome, a condition in which new weakness and pain occurs years later in previously affected muscles.

Polio cases have decreased by over 99% since 1988, from an estimated more than 350,000 cases to 1919 in 2003. The reduction is the result of the global effort to eradicate the disease. The seven polio-endemic countries/areas, from highest to lowest risk of ongoing transmission beyond mid-2003 are northern India, northern Nigeria, Egypt, Pakistan, Afghanistan, Somalia and Niger.