Jessica Durando

USA TODAY Network

Officials in 10 states are reporting cases of respiratory illness, some severe enough to send children to hospitals.

In Kansas City, Mo., more than 300 cases of respiratory illnesses were reported last month, according to the state Department of Health and Senior Services. About 15% of the illnesses resulted in children being placed in an intensive care unit, according to a health alert issued Aug. 29.

Ten states have contacted the Centers for Disease Control and Prevention for help in investigating enterovirus — Colorado, North Carolina, Georgia, Ohio, Iowa, Illinois, Missouri, Kansas, Oklahoma and Kentucky, according to WXIA-TV.

Enteroviruses, with symptoms similar to an intense cold, hits its peak in September, according to medical officials.

But it is unusual that there have been so many hospitalizations, CNN reports.

The number of hospitalizations reported could be "just the tip of the iceberg in terms of severe cases," Mark Pallansch, director of the CDC's Division of Viral Diseases, told CNN.

Pallansch said the division is looking into the situation.

Cincinnati medical officials admitted a record number of children to a local hospital over the weekend. Although there's been no confirmed cases of the enterovirus at Cincinnati Children's Hospital Medical Center, officials admitted 540 patients Friday, said Dr. Derek Wheeler, associate chief of staff at the hospital.

The previous record was around 515, Wheeler said.

"We're just seeing the (increased) volumes, we haven't seen (patients) sicker than usual yet," he said.

While hospitals from other states have placed restrictions on visitations, Wheeler said there are no plans to do that in Cincinnati.

The virus is similar to what doctors treat during cold and flu season. That means nothing really changes if a child comes down with the rare virus, he said.

"The bottom line is this is a virus you wouldn't treat with antibiotics, so other than the (high-level of) interest, there's no reason we would need to know it's an enterovirus," Wheeler said.

In Kentucky, Kraig Humbaugh, deputy commissioner of the Kentucky Department of Public Health, said the CDC recently confirmed that five of 10 cases it tested from Kentucky were enterovirus D68.

"We're seeing more than the usual number of cases," Humbaugh said, adding it has ranged from mild cold-like symptoms to hospitalizations.

At Kosair Children's Hospital in Louisville, about 100 children in August tested positive for one of two viruses that include an enterovirus, but officials can't be certain how many if any might be D68.

"We have seen an increase in kids admitted to the ICU with respiratory illness," said Kris Bryant, an epidemiologist at Kosair and a pediatric infectious disease specialist with University of Louisville Physicians.

WXIA-TV News medical correspondent Dr. Sujatha Reddy said children with asthma or allergies are the ones who are suffering the severest side effects of the virus.

"If you see your kid's condition changing — they're going just from having the sniffles to a fever to now, perhaps, difficulty breathing, or they just look like they don't feel good — you want to take them to the doctor or to the emergency room to make sure," Reddy said. "Because these kids that have asthma (or allergies) and get this enterovirus can get very ill."

This particular type of enterovirus — EV-D68 — is uncommon, but not new. It was first identified in the 1960s.

An analysis by the CDC showed at least 19 of the Kansas City children tested positive for EV-D68, according to the Missouri Department of Health and Senior Services.

A vaccine for EV-D68 isn't available.

"Many infections will be mild and self-limited, requiring only symptomatic treatment," the analysis said. "Some people with several respiratory illness caused by EV-D68 may need to be hospitalized and receive intensive supportive therapy."

"The virus just runs its course. The illness goes away by itself," Reddy said. "But for kids who may have asthma or may have bad allergies, or have some other underlying medical problem, they're the ones that, potentially, could get more sick."

At Children's Hospital in Denver, 447 kids with respiratory complaints came to the emergency department Sept. 4-7. Of those, 39 were admitted to the hospital for treatment, said Chris Nyquist.

"Young children are having a tougher time," said Nyquist, a pediatric infectious disease specialist. "It is a huge upswing in the numbers we're seeing."

Nyquist said parents are alarmed because in some cases kids without any previous asthma symptoms start wheezing after coming down with what appears to be a common cold. She said a small number of kids have required intensive care and breathing assistance from ventilators, but there have been no reported deaths.

Nyquist said the hospital initially ran low on supplies to treat the asthma complications but has caught up now. The illness is driving a 12-15% increase in overall ER visits compared to this time last year.

She said kids with uncontrolled asthma are at greatest risk for serious illness. Those with no history of breathing problems will recover quickly, Nyquist said.

"Most of the children really do just fine," she said. "That's the scary part — the unpredictability of it."

Rocky Mountain Hospital for Children in Denver had five children in intensive care and 20 more in the pediatric unit, KUSA-TV reported last week.

"This is the worst I've seen in my time here at Rocky Mountain Hospital for Children," Raju Meyeppan told the station. "We're going to have a pretty busy winter at this institution and throughout the hospitals of Denver."

Will Cornejo, 13, was among the children in intensive care at Rocky Mountain after he came down with a cold and then woke up Tuesday night with an asthma attack that couldn't be controlled with his medicine albuterol. His mother, Jennifer, called 911 when her son's breathing became shallow, and her son was airlifted to the Denver hospital, she told KUSA.

In Cincinnati, Wheeler said parents can prevent their children from getting the virus by making them wash their hands frequently and drink plenty of fluids.

If they do suspect their child contracted the virus, he suggested parents call their pediatrician first because urgent care facilities will be busy.

Doctors recommend disinfecting school supplies, pens, pencils — even a child's cellphone.

And parents should keep sick children home from school.

Contributing: Michael Martinez, John Newsome, Elizabeth Cohen, Kyle Dyerm, Trevor Hughes and Keith BieryGolick.