Mystery virus sickens 1,000+ children across US

LOS ANGELES (KABC) -- More than 1,000 children in 10 states have been sickened by a mysterious virus, and doctors are warning it could become a nationwide problem. Public health officials are concerned the outbreak could be headed to California.

Health officials suspect that it is a rare respiratory virus called human enterovirus 68. It starts like the common cold, but then quickly progresses, sending kids to the hospital, unable to breathe. The illness is similar to asthma or respiratory distress, with symptoms like coughing, difficulty breathing and sometimes wheezing and fever.

There is no anti-viral therapy or vaccine yet. Health officials say children with asthma and those under the age of 5 are the most vulnerable. Pediatricians say it's because kids have smaller airways and their immune systems aren't as developed. However, public health experts say they do expect to see more adult cases as the outbreak spreads.

In one severe case in Colorado, 13-year-old asthmatic patient Will Cornejo ended up in the emergency room a day after showing basic cold-like symptoms. His asthma became so severe on the second day that the teen turned blue and was rushed to the emergency room, where doctors gave him an emergency breathing tube.

"My head started hurting after my lungs sort of started closing up," said Cornejo.

Pediatric infectious disease specialist Dr. Pia Pannaraj says it can progress quickly.

"With this illness there is a lot of wheezing, so it's because they can't get the air in and out of their lungs properly, so they make a noise as they exhale," said Pannaraj.

Infectious-disease specialists say enterovirus 68 was first identified in the 1960s in California. There have been pockets of illnesses ever since. But this year scientists suspect the virus has changed.

"It's possible that the virus evolved somehow so that it spreads more easily from person to person," said Pannaraj.

Which is why it's very likely the virus will be spreading through Southern California soon. Many parents are already on high alert.

As always, the best defense is to get plenty of sleep, eat whole foods and keep hands clean with constant washing. But if symptoms go beyond a bad cold, Pannaraj says you should head to the emergency room.

"Particularly if they aren't eating properly, aren't sleeping properly, and just can't breathe, especially if they are turning blue," said Pannaraj.

States that have been affected include Missouri, Kansas, Illinois, Kentucky, Iowa, Colorado, Ohio, Oklahoma, North Carolina and Georgia.

"Viruses don't tend to respect borders," ABC News Chief Health and Medical Editor Dr. Richard Besser said. "It is only 10 states now, but it's going to be across the country. So if your state doesn't have it now, watch for it, it's coming."

ABC News contributed to this report.