ST. PAUL, Minn. (AP) — Hospitals in the Twin Cities are unusually busy treating children with severe respiratory problems that match the symptoms of an uncommon virus that’s sickened children in at least a dozen Midwest states, but the presence of enterovirus 68 has yet to be confirmed by the state Department of Health.

The region’s largest pediatric hospital system, Children’s Hospitals and Clinics of Minnesota, said it had to divert six patients to another hospital this week because its beds are full of kids with severe respiratory symptoms. Many children who have had greater difficulty breathing were given doses of vaporized medicine, according to Roxanne Fernandes, the hospital’s chief nursing officer.

“We stream that (the medication) to them through a mask continuously,” she said. “And some children are having what we call continuous nebulization for a few days, and this is very unusual.”

Children’s emergency departments treated 90 children with severe symptoms on Wednesday, Fernandez told Minnesota Public Radio. The clinic normally sees about 20 children for breathing problems this time of year, according to Fernandez.

“We have also heard from our community pediatric clinics that have urgent care and open appointments that they’re seeing an unusual number of children,” she said, adding that most of them were well enough to be sent home.

Federal health officials have asked physicians throughout the country to keep an eye out for symptoms associated with enterovirus 68. The respiratory illness can’t be treated with antibiotics, and there isn’t a vaccine to prevent it, but the spread of the virus can be slowed by hand washing and covering coughs.

Many cases of the disease may be mild enough that they don’t require treatment, according public health officials.