ATLANTA – Implementing surveillance programs at area hospitals is an effective tool for health care providers and public health officials to identify severe acute respiratory illness (SARI) and enterovirus specifically early.
“We do surveillance for respiratory illness [at] three sentinel sites that participate in the Minneapolis-St. Paul metro area,” explained Hannah Friedlander, an epidemiologist with the Minnesota Department of Health in St. Paul, who presented the study. “[But] our surveillance didn’t actually actively look for enterovirus, it looked for rhinovirus, which is known to cross-react with enterovirus on PCRs [polymerase chain reactions],” she said at the International Conference on Emerging Infectious Diseases
Hannah Friendlander
To remedy that, the surveillance program – which involves the participation of one pediatric hospital, one hospital serving both children and adults, and one primarily serving adults – added testing for enterovirus to PCRs of all SARI specimens collected from Sept. 1 through Oct. 31, 2014. In total, 363 SARI specimens were collected over that time frame, of which 100 (28%) were found to be pan-EV positive and underwent further evaluation for EV-D68. Ultimately, 64 of the EV-positive specimens were found to be EV-D68 strains.
The vast majority of cases identified as being caused by the EV-D68 strain (73%) were collected between Sept. 6 and Sept. 20.
This indicates that starting surveillance of SARI cases when enteroviruses traditionally become more frequent could allow for faster determination of which strain is most prevalent and what the optimal treatment should be.
“It’s hard to say if this was surprising because we hadn’t previously been looking for enterovirus, so we don’t have another year to compare [these] data to,” Ms. Friedlander explained. “But I think it’s surprising that we saw as much of [enterovirus] as we did.”
Most cases of EV-D68 (64, or 36%) were in patients between the ages of 5 and 11 years, with a median age of 6 years. A total of 52 (81%) EV-D68 cases presented with shortness of breath, and 31 cases (48%) presented with wheezing or cough. Hospital stays of 4 days or fewer occurred in 73% of cases, with a median stay length of 3 days; 33% of EV-D68 patients required admittance to the ICU, and 13% of EV-D68 patients were placed on a mechanical ventilator at some point during treatment.
“This fall is our third year doing this type of surveillance, so at the time the data for this [were] collected, we only had 1 year of surveillance under our belt,” explained Ms. Friedlander. “We now look prospectively for enterovirus, not EV-D68 specifically, so it’ll be interesting to see as the years go on if this was an outlier year.”
Ms. Friedlander and her coinvestigators say they hope that further SARI surveillance will shed more light on the trends of viral pathogens and the impact that these have on hospitalization rates. They implore hospital systems to not only have surveillance programs in place, but also for them to have the flexibility to include additional testing should the need for it arise. That flexibility, Ms. Friedlander said, is what proved crucial in the early identification of EV-D68 in her own study population.
This study was funded by the Council of State and Territorial Epidemiologists, and the Centers for the Disease Control and Prevention. Ms. Friedlander did not report any relevant financial disclosures.