Rapid Molecular Test Developed for Enterovirus D68

Every year, enteroviruses and rhinoviruses cause millions of respiratory illnesses in children and this year, EV-D68 has been the most common type of Enterovirus identified, leading to increases in illnesses among children and affecting those with asthma most severely.

Scientists at the US Centers for Disease Control and Prevention (CDC; Atlanta, GA, USA) developed a real-time reverse transcription polymerase chain reaction, (rRT-PCR), and it identifies all strains of EV-D68 that have been seen this summer and fall. The new test has fewer and shorter steps than the test that the CDC and some US states were using for the EV-D68 outbreak and the new test allows for more specimens to be tested at the same time.

The CDC has tested 1,163 specimens submitted by hospitals and from 45 US states. Of the specimens tested by the CDC laboratory from August 1, 2014, to October 10, 2014, about half have tested positive for EV-D68. About one third have tested positive for a rhinovirus or an Enterovirus other than EV-D68. The new laboratory test will allow the CDC to process the approximately one-thousand remaining specimens at a much faster rate. The most suitable specimens are nasopharyngeal and/or oropharyngeal swab which give a high diagnostic yield or other respiratory specimens such as nasal wash or aspirates. Serum specimens have an expected low yield.

Viral ribonucleic acid (RNA) is extracted using QIAamp Viral RNA Mini Kit (Qiagen; Valencia, CA, USA) and the rRT-PCR was performed using the SuperScript III Platinum One Step qRT PCR Kit (Invitrogen; Carlsbad, CA, USA) and the AB 7500 Real Time PCR Systems (Applied Biosystems; Foster City, CA, USA). The CDC expects to complete testing of the remaining specimens that were received since mid-September within about 7 to 10 days; going from testing about 40 specimens per day to testing up to 180 per day. This will allow them to then test and report results for new specimens within a few days of receiving them.

The outcome of the EV-D68 test is to collect surveillance data to help public health officials target the responses to the outbreak, and not to determine the treatment plan for a specific patient. The CDC prioritized testing for the most severe cases since the outbreak began in August 2014 to get a better understanding of the disease.

Related Links:
US Centers for Disease Control and Prevention
Qiagen
Invitrogen