In the United States the number of cases of Enterovirus D68 has been on the rise. Between 1970 and 2005 there have been 26 cases according to a CDC surveillance survey. Those numbers seem minuscule when compared to this year's caseload, which so far includes 825 people across 46 states.
Enterovirus is not a new virus as it was first seen in 1962 among four kids in California. Since then scientists have seen EV-D68 occur throughout the world in clusters, and in different forms. Infection with EV-D68 was often linked with mild cold symptoms such as runny nose, sneezing, coughing and fever.
The cases that have occurred within the past year have been linked to more severe symptoms especially among children with breathing problems, says Rafal Tokarz of Columbia University. This has lead to increased concern from parents who have read headlines like "Michigan toddler dies of enterovirus D68". But parents' heightened concern may not be warranted as doctors are not sure if toddler actually died from the virus infection.
It has also been postulated that EV-D68 has not changed significantly but that scientists have just gotten better at finding it. In the past, people often found EV-D68 when they were looking for other viruses, Tokarz states. When Tokarz and his colleagues went looking for influenza in New York a few years ago he found that their was a sizable cohort of people that had EV-D68. Scientist do think that the enterovirus could have mutated to become more transmissible but the genome released by the CDC has not shown any obviously important mutations. Further analysis of the genome would have to be conducted to obtain more conclusive data.
In the mean time doctors are saying to not worry about the virus too much as the number of EV-D68 cases are predicted to dwindle as the colder season approaches.