Article content

OTTAWA — Lyme disease has settled so deeply into parts of Canada many public health units now just assume if you get bitten by a tick, you should be treated for Lyme disease.

In Ottawa, where more than two-thirds of the ticks tested in some neighbourhoods carry the bacteria that causes Lyme disease, the public-health unit no longer bothers to test ticks at all.

We apologize, but this video has failed to load.

tap here to see other videos from our team. Try refreshing your browser, or Lyme-spreading ticks so common thanks to mild winters, some places stop testing Back to video

Dr. Vera Etches, the unit’s top doctor, said that in 2016 and 2017 more than one-fifth of black-legged ticks tested in Ottawa came back positive for Lyme.

“That’s a threshold,” she said. “Once you know that more than 20 per cent of the ticks in your area carry Lyme disease bacteria then we don’t need to check in on that. That is what we now call an ‘at-risk area.’ ”

That means if a tick is found on a person, and is believed to have been there for more than 24 hours, then the patient should get antibiotics to prevent Lyme infection, even without any testing of the tick. It takes 24 hours before bacteria in the tick’s gut move to its salivary glands and are transferred to a person.