OKLAHOMA CITY (AP) — Dozens of respiratory syncytial virus cases have been reported to the state Health Department this year, an illness that occurs mostly in infants and toddlers.

Like flu, the respiratory disease season lasts from late fall until spring. As of Dec. 13, 145 cases had been reported.

“That’s pretty much on track with what we’ve seen in the last couple years,” state epidemiologist Dr. Kristy Bradley said.

Children and older people with heart and lung issues can also be vulnerable to RSV.

“By the time a child is 2 years old, they have usually been exposed to RSV,” Bradley said. “As you get older, you can still get infections, but it’s more like a mild threat.”

Bradley said parents can protect babies by covering them in public and limiting their exposure to crowds. Frequent handwashing also can help deter the spread of the virus.

There is no treatment for RSV other than hospitalization to monitor breathing. The state does not track RSV deaths.

“RSV is the most common cause of hospitalization in infants under 1 year old,” said Dr. Casey Hester, a pediatrician at OU Medical Center.

She said children who had RSV may be more likely to develop wheezing and asthma-like symptoms at a later time.

The illness is transmitted through nose and throat secretions.

In adults, it produces mild, cold-like symptoms. But for very young patients, older people or those with chronic health conditions, the virus can lead to pneumonia and even death.