This possible Illinois cases is believed to be the North American strain of hantavirus, which is not spread from person to person, like the Andes strain that struck the cruise ship in the Atlantic.
Rotavirus causes severe dehydration in infants and young children -- it is a big killer of babies in developing countries but not as much in the United States and Europe.
The extreme contagiousness of the measles in unvaccinated people has local health experts closely watching for any sign of possible spread in the St. Louis area following a case that recently passed through Lambert Airport.