Poliomyelitis (polio) is a viral infection that is spread person-to-person through the fecal-oral route. Children who have polio shed the virus in their excrement (poop). It is most commonly spread through unclean hands, contaminated food, and untreated water. Some people with people will have no symptoms or mild symptoms. For others, polio infects the spinal cord and can cause permanent paralysis or even death.