Over a one-year period, five children in California developed a polio-like illness that caused severe weakness or paralysis in their arms and legs, a new case study reports. In two of the children, their symptoms have now been linked with an extremely rare virus called enterovirus-68. Like the poliovirus, which has been eradicated in the U.S. since 1979 thanks to the polio vaccine, strains of enterovirus in rare cases can invade and injure the spine. These are the first reported cases of polio-like symptoms being caused by enterovirus in the United States. During the last decade, outbreaks of polio-like symptoms...