A virus that has sickened children across the country — in some cases causing severe breathing woes — is also circulating in California, state and local health officials confirmed Thursday.

Four children from San Diego and Ventura counties have tested positive for infection with enterovirus D68, state epidemiologist Dr. Gil Chavez said, adding that it was likely more confirmed illnesses would emerge in coming weeks.

“As time goes by, we’ll find additional cases,” he said in a phone call with reporters.

The sickened boys and girls ranged from 2 to 13 years of age and had been hospitalized after developing respiratory distress. Three had histories of asthma, Chavez said.


All were treated at Rady Children’s Hospital in San Diego, said San Diego County health officer Dr. Wilma Wooten.

The cases are unrelated and are not considered to be a cluster.

Chavez called enterovirus D68 “a known foe.”

First identified in 1962, EV-D68 belongs to a large family of viruses that cause an estimated 10 million to 15 million infections in Americans every year, according to the U.S. Centers for Disease Control and Prevention.


Generally, illnesses from enteroviruses are mild, occur in late summer and fall, and affect children more severely than adults, Chavez said. EV-D68, which is reported less frequently than many other enteroviruses, is known to cause cold symptoms such as runny nose, sneezing and coughing.

But in some instances, particularly in children with asthma and other respiratory problems, it can also bring about wheezing and difficulty breathing severe enough to require hospitalization.

Such severe cases first set off alarms among public health investigators this year, said Dr. Susan Gerber, team lead for respiratory viruses in the CDC’s viral diseases division.

Hospitals in Missouri and Illinois reported increases in severe respiratory illnesses in kids, compared with similar time frames in previous years.


After testing revealed that EV-D68 was the predominant strain in those outbreaks, the CDC and state health departments stepped up efforts to detect and understand the virus.

As of Thursday morning — before California’s update — the CDC was reporting that 153 people in 18 states had confirmed cases of EV-D68 infection. None of the illnesses have been fatal.

California’s public health agency discovered the state’s four cases after asking local health departments to send in nose and throat swabs from hospitalized children with similar severe respiratory illnesses.

Rady Children’s Hospital began sending samples for testing after doctors noticed an increase in respiratory illness, Wooten said.


Dr. John Bradley, director of the hospital’s infectious disease division, said that about 30 to 40 children were now admitted for respiratory illness, about 20% more than physicians usually see this time of year.

The hospital tested the kids for various viruses. Of the cases where initial tests suggested a child might have EV-D68, about half were confirmed positive through more sophisticated tests in state laboratories. Five more samples are pending.

Bradley said the infected kids recovered quickly, with breathing support.

In a statement, the Los Angeles County Department of Public Health said that no cases of EV-D68 had been found in the county.


At Children’s Hospital Los Angeles, doctors have not seen an uptick in respiratory illnesses and have not yet submitted samples for testing to the state, said infectious disease specialist Dr. Pia Pannaraj.

But she said that the hospital expected sickened kids to come in “at some point” and was getting ready to handle cases as they emerged — preparing the intensive care unit to treat more children needing increased respiratory support, for instance.

Parents of children with asthma should make sure they have up-to-date medications for their child on hand, and have an “asthma action plan” worked out with their doctor in case the child gets sick, said Dr. Robert Levin, health officer for Ventura County.

But parents of children without underlying respiratory conditions should also take heed if their child’s coughing or wheezing symptoms become particularly severe.


Many children sickened by EV-D68 this year have not developed fevers, Levin said.

“Any child who’s having trouble to the point where they need to catch their breath is a kid that parents need to take in,” said Bradley, of Rady Children’s Hospital. “It’s common sense.”

Public health officials are also urging all Californians to take routine precautions to limit the spread of the virus — frequent hand washing, covering coughs and sneezes, and keeping sick kids home from school or activities.

Ventura County’s Levin said that EV-D68 had probably been circulating in California all along over the last 40 or 50 years, but because known cases were few and far between — and because diagnostic technology wasn’t good enough to rapidly identify the bug — people were never aware of it.


“If it were 20 or 30 years ago and this had happened, people would say, the flu season is starting early this year,” he said. “But maybe it wasn’t the flu. Maybe it was this.”

He said he thought the cases of severe illness were probably “the tip of a large iceberg,” with many EV-D68-infected kids never getting sick enough to need respiratory support or viral testing.

eryn.brown@latimes.com

Twitter: @LATErynbrown