There is evidence linking a new form of the Enterovirus to muscle weakness and paralysis.
Health officials say four more New Jersey children have confirmed cases of a respiratory illness that's caused by an uncommon virus.
It's been more than 72 hours since parents learned of the death of a 4-year-old boy who was enrolled at Yardville Elementary School in Hamilton Township, New Jersey.
Health officials are investigating nine cases of muscle weakness or paralysis in Colorado children and whether the culprit might be a virus causing severe respiratory illness across the country.