Eightfold increase of enterovirus D68 in 2014

A study released by the BC Centre for Disease Control shows an eightfold increase in enterovirus D68 (EV-D68) detections from October to December 2014, compared to the same period in 2013.

The study, “Systematic Community- and Hospital-Based Surveillance for Enterovirus-D68 in three Canadian Provinces, August to December 2014,” is one of the first to look at both community and hospital cases of EV-D68 during the 2014 outbreak in North America. The study describes the EV-D68 epidemic activity in Canada during the fall of 2014, during which over 200 cases were detected in British Columbia alone.

EV-D68 is a respiratory virus that causes mild to severe illness, with symptoms ranging from runny nose, sneezing, and coughing to wheezing and difficulty breathing. Children with a history of asthma or wheezing are at higher risk for serious complications.

The EV-D68 strain that circulated in BC during the fall of 2014 was found to be similar to other strains globally, including those that caused the 2014 outbreak in the US. Two surveillance systems were used to learn about patient risk for EV-D68: community-based testing of patients with symptoms similar to influenza-like illness in three provinces (BC, Alberta, and Quebec), and testing patients who were admitted to hospital with severe respiratory illness in BC.

Investigators confirmed and quantified a widespread epidemic during the fall of 2014 and, because monitoring was applied across the entire population of BC, they could calculate and compare the actual incidence of EV-D68 hospitalizations by age. They found that an equal proportion of children and young adults who sought care from a general practitioner for flu-like illness tested positive for EV-D68, suggesting susceptibility across a wide range of age groups; however, children were hospitalized at a higher rate compared to adults.

Children under the age of 10 had a four- to fivefold higher rate of hospitalization related to EV-D68 than children between the ages of 10 and 19, and were hospitalized at rates fifteen- to twentyfold higher than adults.

Unique to the 2014 outbreak, five cases of acute flaccid paralysis, a condition defined by neurological symptoms and extreme muscle weakness, were identified in BC, with symptoms persisting more than 9 months later. Three deaths were also reported, although it remains unclear if EV-D68 infections caused these severe illnesses. The three patients who died all had underlying conditions or co-infections that likely contributed to their cause of death. The BC provincial laboratory has been continuing to test for EV-D68 in 2015, with no cases found in August or September of this year. Ongoing surveillance in both community and hospital settings is needed in order for investigators to learn more about the disease incidence and potential at-risk groups.

Enterovirus can be spread from person to person when an infected person coughs or sneezes. It can also be spread by having close contact, such as touching or shaking hands, with an infected person or by touching contaminated objects or surfaces. There is no specific treatment or vaccine for EV-D68, but simple measures like frequent hand washing and staying home if sick can help prevent the spread of respiratory viruses like EV-D68 or influenza.

Dr Danuta Skowronski, physician epidemiologist at BCCDC, is the lead investigator in this study. The study is published in EuroSurveillance and is available at www.eurosurveillance.org/ViewArticle.aspx?ArticleId=21283.