Test identifies EV-D68 cases

Ninety-six cases of the respiratory virus known as EV-D68 have been diagnosed in Hamilton over the past month. In most cases, the enterovirus strain causes symptoms similar to the common cold, but young children — especially those with asthma — are most susceptible. CHCH was given a tour of a Hamilton laboratory that created a test to make it possible to identify the virus.

The Hamilton Regional Laboratory Medicine Program’s virology lab is located here at St. Joseph’s and this is where they developed what they believe is the only test — in Ontario at least — that specifically detects EV-D68.

It’s only been up and running since the weekend.

Candy Rutherford is a technical specialist in molecular microbiology and virology: “I think I’ve put through something like 221 specimens so far.”

But the test created by Candy Rutherford has already helped identify 96 cases of EV-D68 that have popped up in Hamilton over the last month.

Candy Rutherford: “For specificity, we tested this assay against rhinovirus, a number of other enterovirus type organisms like echovirus coxsackie and it was negative in all of that. It was only ever positive for this.”

The Hamilton Regional Laboratory Medicine Program already had a test for all rhinovirius and enterovirus as a group.

Dr. Marek Smieja, HRLMP head of virology: “That test was very good but it didn’t tell us which one it was and usually we don’t need to know that. On very rare occasions, we’ll do additional testing.”

This time of the year, the spread of enterovirus and rhinovirus is very common. However, head of virology Dr. Marek Smieja says the decision to create a specific test for D68 came after reports of large outbreaks of the strain.

Dr. Marek Smieja: “It’s unusual that one strain would dominate so much. And so, we developed it in part just to keep tabs on it, to make sure we understand what it’s doing.”

Patients are given a swab through the nose into the back of the throat. It’s then tested in the lab for 10 different viruses. And if rhino or enterovirus are detected, they will then go on to further test for D-68.

Candy Rutherford: “Now the reactions are in the rotor gene which is this instrument here. The rotor gene is going to perform realtime PCR to amplify enterovirus D68 in the samples that we put into it.”

The outcome is presented in a graph. The curved lines represent patients who have tested positive. From the time of the first swab, it can take up to the next day to get your results back.

Just like the common cold, there is nothing doctors can prescribe to fight EV-D68. Dr. Smieja says while they don’t expect the strain to do anything unusual, they’re rather erring on the side of caution and monitoring EV-D68 just to make sure.