Keeping a Finger on the Pulse: Establishment of Surveillance for Enterovirus D68 Monitoring

BACKGROUND: In September 2014, the Centers for Disease Control and Prevention (CDC) informed state health departments of an observed increase in severe respiratory illness among children in two Midwestern states. CDC identified enterovirus D68 (EV-D68) from specimens collected from these children. New Jersey Department of Health (NJDOH) wanted to begin monitoring for EV-D68; however, enteroviruses are not reportable in New Jersey thereby creating a need for specialized surveillance. NJDOH implemented a three tiered surveillance approach in an effort to monitor for the presence of EV-D68 in the state.   

METHODS: The first surveillance mechanism set up was a passive system relying on individual case reports. A health alert message was sent to public health partners requesting reports of patients meeting surveillance criteria. Criteria were defined as pediatric patients with clinically compatible illness and admission to an intensive care unit; adults with clinically compatible illness and admission to the hospital; clusters of respiratory illness; and any respiratory associated deaths. Partners completed a case report form which was faxed to and reviewed by NJDOH. Approved specimens were requested for enterovirus testing at CDC. A sentinel laboratory system, mirrored after influenza surveillance, was the second surveillance system developed. Laboratories that conducted enterovirus/rhinovirus testing were asked to voluntarily report total tests performed and total positives each week and to submit the first two  positive specimens per week for testing at CDC. Finally, emergency department (ED) syndromic surveillance systems were used to monitor increases in visits for children less than 17 years. An EV-D68 classifier (shortness of breath, wheeze, and asthma) was created and assessed daily and weekly.  

RESULTS: Passive surveillance generated 48 reports (3 not approved, 3 approved/not received, 42 sent to CDC). Sentinel surveillance generated 51 specimens from 3 facilities. Thirty-eight EV-D68 cases were identified. From MMWR week 34 to 45 (time period which EV-D68 were identified), there were 13,923 ED visits associated with the syndrome classifier representing an average of 8.16% of all ED visits in this age group.

CONCLUSIONS: Establishing surveillance to monitor an emerging non-reportable disease can be challenging. A single source of data (i.e., lab data) will likely not be enough to determine both temporal and geographic spread of the disease as well as clinical and epidemiologic information from cases. Establishment of a multi-tiered surveillance approach along with leveraging existing surveillance systems and relationships can ensure that a robust system can be quickly implemented to monitor emerging diseases, such as EV-D68.