A spike in children hospitalized in the Twin Cities for breathing problems has coincided over the past month with an unusually nasty strain of enterovirus that has been spreading through the Midwest.

Whether any Minnesota children have been infected with enterovirus D68 won't be known until lab tests confirm the virus, but officials at two pediatric hospitals in Minneapolis said their emergency rooms and inpatient units are full of children suffering labored breathing and wheezing — symptoms associated with the strain.

"This is not back to school, this is not business as usual," said Roxanne Fernandes, chief nursing officer for Children's Hospitals and Clinics of Minnesota. "In the last 24 hours, we've seen 90 children in our emergency room with respiratory illnesses. That is not typical."

Leslie Smith brought her 4-year-old daughter, Kennedy, to her family doctor after labored breathing prevented her from sleeping early Monday at their home in Brooklyn Park.

"I came up and checked on her and she had crawled off the couch and was laying on the floor and she just looked up like, 'Mom, help me, help me,' " Smith said. "She literally said 'I can't breathe.' That's when I grabbed her up and we left."

The doctor called 911 and mother and daughter were taken by ambulance to children's.

A normal daily number of emergency department visits at Children's Minneapolis and St. Paul ERs combined would be around 230 children at this time of year, but the two hospitals combined have been seeing an average of 313 children per day for the past week — a 36 percent bump. The initial theory last week was that children were suffering problems at the peak of ragweed season, and trading germs now that they were back at school. But the number of ER visits kept increasing, Fernandes said.

On Monday, the Children's hospitals were full and had 25 children with respiratory problems waiting in their two ERs for inpatient beds to open up. Staffing was increased to add nurses, orderlies and even interpreters — as 38 families speaking 12 languages other than English brought in children struggling to breathe that day.

The University of Minnesota Children's Hospital has similarly seen an increase in patient care that it would normally associate with winter and the cold and flu season, said spokeswoman Caroline Marin.

So far, none of the children has tested positive for enterovirus D68, an unusual strain of an otherwise common virus that has been suspected since mid-August of infecting children in 12 states and has been confirmed in six states including Iowa, Missouri and Illinois.

Minnesota is part of a group of states that reports enterovirus cases by their strains to federal health authorities, and has reported cases of the D68 strain in each of the last three years. Late summer is when it commonly pops up, said Doug Schultz, a spokesman for the state health department. But the intensity of the illnesses has surprised health and hospital officials in the Midwest.

Other states have observed that persons with underlying health problems, particularly asthma, are at the greatest risk from infection with enterovirus D68, Schultz said. "They should be in close contact with their health care provider if they develop respiratory symptoms that are not getting better with their regular recommended treatment regimens," he said.

While news of a somewhat mysterious viral outbreak has generated public attention and concern, Fernandes said, she doubts that the influx of cases at Children's is just worried parents reacting to the news when their children have the sniffles. If that were the case, the rate of ER visits resulting in hospital admissions would be going down, she said. It actually has been going up, along with the total number of visits. She said 15 percent to 18 percent of children with respiratory problems in the ER are being admitted for inpatient care.

Still, Fernandes noted that the vast majority of children with these respiratory symptoms don't suffer severe problems, and that most are sent home from the ER. No deaths have been reported at Children's related to the run of respiratory illnesses either.

Smith said her daughter's labored breathing was a surprise because she doesn't have asthma and is generally a healthy girl who loves to play basketball, paint and watch the Vikings. Inhaled medications are keeping her breathing calm but she developed pneumonia. Smith is staying bedside with her daughter and said she is in no rush to get her home.

"I'd rather just have her here," she said, "where she can be comfortable and taken care of and nursed back to health."

Jeremy Olson • 612-673-7744