IDWeek 2014: Emerging enterovirus D68 infects 664 children in 45 states, but remains a mystery on many fronts

March 18th, 2015

Philadelphia: An aggressive strain of enterovirus D68 (EV-D68) has hospitalized hundreds of children with severe respiratory infections and has caused more deaths in the U.S. than Ebola.

While the first case of Ebola diagnosed in the U.S. died Oct. 8, five patients who tested positive for EV-D68 have died since the virus rapidly emerged last August. However, epidemiologists need more evidence to definitively say the enterovirus was the cause of death. Similarly, a flaccid paralysis syndrome has manifested in some EV-D68 cases, but other children with the condition have tested negative for the virus.

“EV-D68 is a non-polio enterovirus, but it is known that enteroviruses can cause paralysis or similar presentations,” Aaron Milstone, MD, an infectious disease physician at Johns Hopkins said at an Oct. 9 press conference at IDWeek 2014 in Philadelphia. “Whether that is a virus-specific phenomenon or a host phenomenon is something that we are very interested in and there are a number of groups of neurologists looking into this. One thing we don’t know is whether this is a unique virus, whether this virus has changed or whether this virus is just causing such broad disease [that you see a wide range of presentations]. There are probably many, many people out in the community who have had this virus and did not [seek medical care].”

Unanswered questions include whether the children with paralytic syndrome who tested negative for EV-D68 could have previously been exposed or infected with the virus. Another unresolved issue is whether the paralytic syndrome is temporary or permanent.

“To my knowledge no one has thoroughly recovered at this point, but keep in mind that we are in a short-term period right now,” said Mary Anne Jackson, MD, FPIDS, an infectious disease physician at Children’s Mercy in Kansas City, MO. “I am not surprised by that because the recovery would be over weeks to months and not days to weeks.”

Children with a history of asthma appear to be at risk, but any child with a history of or sudden appearance of “wheezing” could be vulnerable to serious infection with EV-D68, says Jackson, whose hospital was one of the first to see a rapid influx of cases of the virus.

“Of [an initial group] of confirmed enterovirus cases a third had underlying asthma, a third had a prior history of wheezing but were not on medication, and a third had never wheezed in the past,” she said. “One of our first messages and guidance for our community pediatricians and families is that if your child has ever wheezed you need to get with your primary care physician to have an asthma action plan that is clear to everyone and can be activated if this child develops any type of respiratory symptoms.”

Hospitalized patients with EV-D68 are under contact and droplet isolation guidelines, which seem to be preventing transmission within the hospital, Jackson says.

“We have not confirmed any [transmission] in my institution at this point,” she said. “Part of the reason we can’t be completely certain is that we’ve identified and confirmed EV-D68 in about 50 patients, but we have about 800 specimens yet to be typed. We know that enteroviruses and rhinoviruses can be nosocomially transmitted. We have one instance where we had a patient who was [already] hospitalized and tested positive [for EV-D68] with mild symptoms, but we have not gotten the test results back on that.”