Children’s hospitals in Denver are experiencing an alarming spike in a severe respiratory illness — especially among very young children and those with asthma — that may be caused by an uncommon viral pathogen.

Officials at Children’s Hospital Colorado said they have treated more than 900 children since Aug. 18 for severe respiratory illness and admitted 86 to the hospital.

“We’ve been seeing a very high volume in our ER, ICU and among hospitalized patients. The hospital is very, very full,” said Dr. Christine Nyquist, a pediatric infectious disease physician. “Kids are getting (the virus) and having asthma complications.”

The suspected virus is human enterovirus 68, a rare virus associated with respiratory illness, according to the Centers for Disease Control and Prevention.

The virus is related to rhinovirus, which causes the common cold, physicians said.

Samples sent to confirm whether it is enterovirus 68 have not yet produced a definitive answer. Similar outbreaks are being investigated in other cities, including confirmed cases in Kansas City, Mo.

At Rocky Mountain Hospital for Children, William Cornejo, a 13-year-old moderate asthmatic, was one of five children whom physicians put on a ventilator this week. His mild cold symptoms developed overnight into a life-threatening illness Wednesday.

“Tuesday evening he had a little cold,” said his mother, Jennifer. “He’s a pretty moderate asthmatic. He’d never gone to the hospital for it since he was 2. I just never dreamed that we needed to go to the hospital.”

After three treatments inhaling albuterol, the medicine used to prevent and treat wheezing, shortness of breath, coughing and chest tightness, William wasn’t any better, his mother said. She was trying to reach his doctor, when she noticed he was unresponsive.

“His lips were blue. He was white as a ghost,” Cornejo said. “I turned him over, and his eyes were rolling back in his head. He was completely limp. But he was still breathing. I called 911.”

Paramedics took him from his Lone Tree home to Sky Ridge Medical Center’s emergency room, where he was stabilized and sent by helicopter to Rocky Mountain. He quickly improved while on a ventilator. He was using just an oxygen mask by Thursday and remained hospitalized Friday, his mother said.

Dr. Raju Meyappan, pediatric critical-care physician at Rocky Mountain said the pediatric floor and ICU are full for this early in the season. Most of the children admitted are 4 years old or younger, he said, although children with asthma or a predisposition for wheezing seem to be hit the hardest.

“They seem to have an abrupt onset and extremely severe reaction to this virus,” Meyappan said. “Keep the albuterol handy. But even with all the right therapy this can happen very, very rapidly.”

It all seemed to happen within an hour with William Cornejo.

“He was OK. Then he was unconscious. It was unreal,” Jennifer Cornejo said. “I thought my heart would come out of my chest. It was so horrible.”

The current epidemic is an early start to what is typically the worst month of the year for children with asthma. More children are admitted to the hospital for asthma attacks in September than in any other month, Nyquist said. The September spike historically has been associated with a variety of factors, such as exposure to germy classmates, high pollen and the beginning of cold and flu season.

Children’s Hospital already has initiated a ban on visits by children under age 13 — a restriction it usually puts in place in November at the height of cold and flu season.

“This is the first time we’ve ever done it this early,” Nyquist said.

Nyquist and Meyappan said parents of children with asthma need to get them on their inhalers, enforce routine hand washing and help them avoid sick people.

Antibiotics don’t work on viruses.

Nyquist also recommended vaccines for flu and pertussis, or whooping cough.

Meyappan said prevention is the key.

“He told me he thought he was dying,” Jennifer Cornejo said of her son.

“He was pretty scared. But he doesn’t remember most of it. Now he’s texting his friends. He’s put a picture on Instagram. He’s better.”

Electa Draper: 303-954-1276, edraper@denverpost.com or twitter.com/electadraper

About human enterovirus 68

Enteroviruses are very common, but outbreaks of enterovirus 68 are rare, according to the Missouri Department of Health & Senior Services, which issued a health alert last week.

The virus appears to spread through close contact with infected people

.

Enterovirus 68 usually causes mild respiratory illness but in some cases can develop into severe illness requiring intensive care and mechanical ventilation, the department said. Symptoms include wheezing or asthma exacerbation.

There is no specific treatment or antiviral medication available for enterovirus 68. Vaccines for preventing the virus also are not available.

The department recommends the following:

• Wash hands often with soap and water for 20 seconds, especially after changing diapers.

• Avoid touching eyes, nose and mouth with unwashed hands.

• Avoid kissing, hugging and sharing cups or eating utensils with people who are sick.

• Disinfect frequently touched surfaces, such as toys and doorknobs, especially if someone is sick.

• Stay home when feeling sick and obtain consultation from your health care provider.