The CDC has developed and begun using a new, faster lab test for detecting enterovirus D68 in specimens from US patients with respiratory illness, according to a press release.
“CDC has received substantially more specimens for enterovirus lab testing than usual this year, due to the large outbreak of EV-D68 and related hospitalizations,” Anne Schuchat, MD, assistant surgeon general and director of CDC’s National Center for Immunization and Respiratory Diseases, said in the release. “When rare or uncommon viruses suddenly begin causing severe illness, CDC works quickly to develop diagnostic tests to enhance our response and investigations. This new lab test will reduce what would normally take several weeks to get results to a few days.”
This year, EV-D68 has been the most common type of enterovirus identified, with an increase in illness among children, particularly those with asthma, the CDC reported.
The new test allows the CDC to more rapidly test the remaining specimens received since mid-September, according to the release. As is similar to other enteroviruses, EV-D68 infections are expected to begin declining by late fall.
The new lab test is a “real time” reverse transcription polymerase chain reaction that identifies all strains of EV-D68 that have been seen during the summer and fall, the release stated. There are fewer and shorter steps than in the prior test being used to identify EV-D68, and the new test allows more specimens to be tested at the same time.
The previous test had been in use by the CDC for about 9 years. Although it was very sensitive and could identify almost all enteroviruses, it was labor intensive and could not be “easily scaled up” to support the testing of large numbers of specimens seen in the current EV-D68 outbreak, according to the release.
The CDC has tested 1,163 specimens submitted by hospitals and 45 states since the EV-D68 outbreak began in August, with about half testing positive from Aug. 1 to Oct. 10, the release reported. Approximately one-third of specimens have tested positive for rhinovirus or a different enterovirus.
“The new lab test will allow us to process the approximately 1,000 remaining specimens at a much faster rate,” the CDC reported.
The real-time lab results combined with hospital admissions data are expected to help the CDC understand when and where the outbreak is ending. Hospitals and states have given informal reports to the CDC that indicate signs of decreasing EV-D68 infections, the release stated. To assess the situation, the CDC is gathering additional information from the states.
The number of confirmed EV-D68 cases is expected to increase substantially in the upcoming days as the CDC tests the remaining specimens it has received since mid-September, according to the release.
“These increases will not reflect changes in real time or mean that the situation is getting worse,” the release stated.
The new lab test will allow for testing up to 180 specimens per day, up from the previous 40 specimens per day, with testing expected to be completed on the samples received since mid-September within 7 to 10 days, according to the CDC.