The federal health monitor has identified the virus that’s sending kids to hospitals with severe respiratory symptoms. So far, the numbers are small and the symptoms are manageable, but questions remain about what else the virus can do.

Many of the children hospitalized in Kansas City, Missouri, and Chicago, Illinois, with a severe respiratory illness are infected with a rare virus called EV68, the Centers for Disease Control (CDC) confirmed today.

“Dozens” of children between the ages of 6 weeks and 16 years tested positive for EV68 in a recent genetic sequencing effort undertaken by CDC staff. Because EV68 is so rare, there’s no other way to test for it.

Most hospitalized children received fluids and medications to open their airways, but at least one was put on a ventilator.

The confirmed cases are localized in the Midwest, but a dozen other states have contacted the CDC to report potential outbreaks. The agency is still investigating those cases and declined to identify the states, but news reports have mentioned Colorado, Georgia, Iowa, Kansas, Kentucky, North Carolina, Ohio, and Oklahoma.

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EV68 gets its name from the common enterovirus family to which it belongs. There are more than 100 types of enterovirus circulating in the United States, and they cause more than 10 million illnesses per year. Most illnesses are respiratory, though some neurological illnesses and some forms of meningitis also stem from an enterovirus. All strains of enterovirus affect children almost exclusively.

EV68 is rare, but not new. First identified in California in 1962, it was almost entirely ignored until it caused clusters of illness in Japan, the Netherlands, and the Philippines in the past couple of years. EV68 circulated among Americans last year, but it didn’t cause much concern.

“This isn’t a new virus,” Dr. Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Diseases, said in a press briefing.

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Even so, the recent spate of cases has led the CDC to put parents and doctors on alert.

“We believe that the unusual increases in Kansas City and Chicago may be occurring elsewhere in the weeks ahead, so we want people to be on the lookout,” Schuchat said.

The best way to avoid the illness is to wash your hands frequently, scrub frequently touched surfaces, and avoid sharing utensils and glasses with others who are sick.

Most children who do get sick will get better on their own, just as they would with any cold or flu. But parents should “absolutely” take children to the doctor if they seem to be having trouble breathing, Schuchat said.

More than half of the 30 children with confirmed EV68 infections have a history of asthma or wheezing problems. Health officials are investigating whether any other conditions may put people at higher risk. In the meantime, they advise parents to pay special attention to symptoms in youngsters with asthma.

The fact that some enteroviruses can cause neurological symptoms seems to be driving a greater level of concern at the CDC than might otherwise be expected in response to just a few dozen illnesses.

“What we know about EV68 is that it can cause mild or severe respiratory illness, yet the full spectrum of all of the illnesses that it can cause are not well defined and that’s something that people are looking into with this virus,” said Schuchat.

Scientists blamed a recent outbreak of a polio-like illness in California on an enterovirus, and some blamed it on EV68.

“Whether we’ll be seeing extended spread of this EV68 or if it’ll just be a few cities affected this year, we just don’t know,” Schuchat said.

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