Poliomyelitis is a disease caused by a virus that usually infects the gastrointestinal system and is capable of damaging the nervous system. Before vaccination was available, cases of poliomyelitis were quite common and left people without use of a limb or total paralysis. The people who became paralyzed were often forced to live inside of an "iron lung" that replicated the action of the abdominal muscle to allow respiration.

In 1955, the first polio vaccine was developed by Jonas Salk using dead viruses. In the 1960s, an oral version was developed, leading to mass vaccination efforts. The effectiveness of the vaccination was immediate and the last reported case of polio infection in the United States was in 1979. The vaccination effort continued through Central and South America, virtually eradicating the virus in the western hemisphere by 1991, although a handful of cases have been reported since.

Since the virus lives in the gastrointestinal system, it usually passes into the body through a person's mouth. The virus is typically transmitted through contact with infected fecal matter or kissing. In most cases, an infected person will not experience any symptoms, but some people will experience paralysis of one or more limbs, respiratory failure, and even death. Although the disease can be contracted by anyone, 50% of the cases occur in children aged 3 to 5. Despite an incubation period of 3-40 days in most people, the paralysis caused by the disease is permanent.

Today, cases of polio are very rare in modernized countries due to the prevalence of a vaccine. Typically, people receive intravenous injections of dead polio viruses four times during their childhood, rendering them immune to the virus. Most cases of infection occur in third world countries that lack the medical facilities to provide thorough vaccination. All travelers to said countries are advised to make sure that they are fully vaccinated and, if not, to get vaccinated before departing.

Many famous people have fallen prey to the ravage of Polio, including former US president Franklin Delano Roosevelt, and Claudius, an emperor of Rome. Ancient Egyptian paintings also appear to depict victims of the disease walking with atrophied limbs and canes.