Two children – one in New York City and one on Long Island – have been diagnosed with Enterovirus D-68.

A New Jersey boy also sought treatment for the severe respiratory illness in Philadelphia. Enterovirus D-68 has already spread in 13 states, largely in the Midwest. Young children with asthma are especially at risk.

“It is a relatively rare form of enterovirus and as a result many infants, children and teenagers have not seen this virus, and they don’t have protection from previous exposures,” said Dr. Lisa Saiman, a professor of pediatrics at Columbia University Medical Center and an attending physician at New York Presbyterian Morgan Stanley Children's Hospital.

She spoke to WNYC’s Amy Eddings.