Poliomyelitis, or polio, is a children's disease. It can affect people of any age, but usually harms kids under 3. The virus spreads by direct person-to-person contact, or through contact with infected mucus or feces. It can rapidly attack the nervous system causing paralysis in just a few hours. Between the middle 1800s and 1900s, polio was a worldwide epidemic. Yet since the development of polio vaccines, the incidence of the disease has plummeted by 99 percent. Today, with the help of the World Health Organization, the Centers for Disease Control and Prevention, Rotary International, UNICEF and the Bill and Melinda Gates Foundation, polio teeters on the verge of eradication.