What happened to enterovirus D68 infections in 2015?

BACKGROUND

Enterovirus-D68 (EV-D68) was observed in association with severe respiratory disease in children in North America and around the world in the fall of 2014.

OBJECTIVE

To compare fall 2014 detection rates with fall 2015 detection rates of EV-D68 in nasopharyngeal swab (NPS) samples collected for routine clinical care from a large regional laboratory in south-central Ontario.

METHOD

Consecutive NPS samples submitted from inpatients and outpatients in Hamilton, Niagara Region and Burlington to the Regional Virology Laboratory were tested with multiplex polymerase chain reaction (PCR) for rhinovirus/enterovirus (as a single target) and for other common respiratory viruses. All NPS samples positive for rhinovirus/enterovirus were reflexed to a lab-developed single target PCR for EV-D68 detection.

RESULTS

In 2014, between August 1 and October 31, 566 of 1,497 (38%, 95%CI 35-40%) NPS samples were rhino/enterovirus positive, of which 177 (31%, 95%CI 27-35%) were confirmed as EV-D68. In 2015, between August 1 and October 31, 472 of 1,630 (29%, 95%CI 27-31%) NPS samples were rhino/enterovirus positive, of which none (0%, upper limit 97.5%CI 0.8%) were confirmed to be EV-D68.

CONCLUSION

Based on testing results, there appears to be much less circulating EV-D68 in south central Ontario in 2015 than in 2014. Further studies would be helpful to determine if detection rates have also dramatically decreased in other regions in Canada and internationally.