Officials at the Centers for Disease Control and Prevention in Atlanta said three patients died from the disease.
"Human enterovirus 68 is not new, but clusters involving large numbers of people with this virus are a recent phenomenon and his may be due in part to improved respiratory diagnostics," CDC officials said. "Human enterovirus infection can cause relatively mild respiratory illness to severe disease, requiring intensive care and mechanical ventilation and death."
Healthcare providers should be aware that human enterovirus is one of many causes of viral respiratory disease, but clusters of unexplained respiratory illness should be reported to the appropriate public health agency, health officials advise.
The findings are published in the CDC's Morbidity and Mortality Weekly Report.