The mysterious viral illness that has been striking children has now spread to 38 states.

The Centers for Disease Control has confirmed 226 cases of enterovirus 68.  However, the CDC admits that many other children have likely been infected with the virus and was not severe enough to seek medical attention at a hospital.

Doctors say the reports of the CDC are the “tip of the iceberg” for the mysterious virus.

University of Chicago’s Medicine Comer Children’s Hospital has been forced to divert ambulances to other hospitals because the emergency room was filled with children suffering from severe respiratory illness.  It was the first time in 10 years the hospital had to divert ambulances.

Doctors say that while enteroviruses are common illnesses, enterovirus 68 is rare.

“Parents would love to know why this virus is causing severe disease and why there are more cases,” Rafal Tokarz, an associate research scientist at Columbia University who has studied the virus, told the New York Times, “but we won’t be able to answer that until a lot more research is done.”