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KANSAS CITY, Mo. — A new respiratory illness to our area is sickening hundreds of kids, and it’s causing trouble in other parts of Missouri, too.

Children’s Mercy Hospital has seen more than 300 cases since mid-August. A doctor there says it is enterovirus 68. The children have difficulty breathing. Ten to 15 percent are needing intensive care.

St. Louis Children’s Hospital says it’s seen more than a hundred kids with similar symptoms in the past week. That hospital, like Children’s Mercy, is full.

A spokesperson for the Centers for Disease Control told FOX 4, “CDC has heard from several state health departments and children’s hospitals about an increase in admissions with severe respiratory illness. We have received samples and are testing to determine the cause or causes.”

But Dr. Mary Anne Jackson, an infectious disease specialist at Children’s Mercy, said samples it sent to the CDC were almost all enterovirus 68.

That virus had been linked to a polio-like illness in several children in California in 2012 and 2013. But the CDC says there is not sufficient data to implicate the virus as a cause. Dr. Jackson said none of the local children have had polio-like symptoms.

To try to stop the spread, Children’s Mercy has posted signs at security entrances saying children 12 or younger should not visit in-patients. Nor should those with symptoms visit.

Dr. Jackson says good hand washing, covering your cough and not sending your child to school if he or she appears sick can help control the spread.

There’s no anti-viral medicine for enterovirus 68 and no vaccine.