Enteroviruses are very common viruses that cause many different types of illness, ranging from mild cold-like symptoms (e.g. runny nose, cough and sneezing) to fever and rash illness to more severe respiratory illness (e.g. difficulty breathing) and neurologic illness (e.g. encephalitis – an infection of the brain – and meningitis – an infection of the lining of the brain or spinal cord). However, most people who get infected by enteroviruses will not get sick at all.
Overall, there are more than 100 different types of enteroviruses. Infants, children and teenagers are more likely to get infections partly because they have not been previously exposed to as many kinds of enteroviruses as adults and have not developed immunity (i.e. protection) to these viruses. In Canada and the United States, enterovirus infections are more common during the late summer and fall.
Enterovirus D68 (EV-D68) is a specific type of non-polio enterovirus. It was first identified in California in 1962 but since then was only rarely reported in the United States compared to other non-polio enteroviruses. In the fall of 2014, EV-D68 was associated with a nationwide outbreak of severe respiratory illness in the United States and Canada. In some patients, EV-D68-associated illness was severe enough to require intensive care unit (ICU) admission.