Amesh A. Adalja, MD, FACP, FACEP, September 12, 2014
The dramatic uptick in the number of children hospitalized with respiratory illness due to infection with enterovirus 68 (EVD-68) in the Midwest is an important reminder that this class of viruses has the capacity to cause severe infection and to stress medical resources. There are more than 100 enteroviruses, and they are responsible for millions of infections each year—most of which are asymptomatic or very minor. However, in recent years certain members of this class of viruses, most notably EV-71, have begun to be considered as serious pathogens; it is clear that EVD-68 is now in this class.1
EVD-68 is not a new virus; it was discovered in 1962 and has been linked to sporadic outbreaks of respiratory illness worldwide. Although it is chiefly associated with respiratory syndromes, it can also cause neurologic disease, sometimes mimicking paralytic polio. The transmission characteristics of enteroviruses include asymptomatic and presymptomatic shedding.1,2
Clusters in the Midwest
Beginning in August, there have been reports in several states of unexplained outbreaks of respiratory illness in children. Many of the children were hospitalized, and some required ICU admission. Diagnostic testing revealed a virus in the rhinovirus/enterovirus family, and further testing confirmed EVD-68 as the culprit. No fatalities have been reported.1
Early data released by the Centers for Disease Control and Prevention (CDC) about these cases reveal that the expected symptoms are present in those afflicted with the virus: cough, coryza, and sneezing. A minority of patients exhibit fever. Strikingly, asthmatics represent a large proportion of those admitted. As there is no specific therapy or vaccination available for enteroviruses, treatment is supportive.1,2
Presence Likely Throughout US
Because of the manner in which enterovirus is spread, it is likely that this virus will appear in many areas of the US, perhaps taking advantage of the opening of schools. Such a scenario underscores the importance of hand hygiene and cough/sneeze etiquette to minimize spread. Because all hospitals are likely to care for patients with upper respiratory symptoms that could be consistent with EVD-68, it is crucial that hospitals be prepared to deal with a possible surge of such patients and to guard against droplet spread of the virus through appropriate infection control.
Another aspect of this outbreak is that testing capacity for this virus may not be available at many hospitals, and such testing will be important for hospitals to gauge the epidemiology and spread of the virus. Some commercial respiratory PCR assays have the capability of detecting—but not distinguishing—rhinoviruses and enteroviruses, and positivity of these tests may be the first indication that the virus is present in the area. Definitive testing for EVD-68 will likely take place at reference labs.
Important questions to be answered regarding EVD-68 are why this virus, known for decades, sparked the current outbreak, and what is the true burden of illness caused by this virus.