A respiratory illness that has already sickened more than a thousand children in 10 states is likely to become a nationwide problem, doctors say.

The disease hasn't been officially identified but officials suspect a rare respiratory virus called human enterovirus 68. According to the U.S. Centers for Disease Control and Prevention, the virus is related to the rhinovirus, which causes the common cold....

Doctors say they are not even sure yet how this particular virus spreads, though the back-to-school season is a normal time for illnesses to spread among children....

At Children's Hospital Colorado in Denver, officials say that between Aug. 18 and Sept. 4, doctors saw more than 900 pediatric patients with symptoms of the respiratory virus in the emergency room. Of those who came in, 86 were admitted into the hospital and a handful ended up in the intensive care unit.