New research sheds light on potentially fatal Lyme disease complications

Female doctor is holding tweezers with a tick. Encephalitis, borreliosis and lyme disease Photo by

After all the restrictions imposed by the COVID-19 pandemic, many Canadians are desperate to break free and enjoy the warmer seasons in the great outdoors. But scientists are cautioning those who head for the woods to be mindful of the black-legged tick: a sesame seed-sized arachnid that can carry the bacteria that causes Lyme disease.

The incidence of Lyme disease in Canada is increasing, as is public awareness of the problem. But the disease can present in many different ways, and Canadian scientists are now shining a light on one rare but particularly fatal condition associated with it: Lyme carditis.

When an infected tick bites a human, the Borrelia burgdorferi bacteria enters the blood stream, causing—often but not always—a bullseye rash around the bite followed by any of a number of symptoms including headaches, joint pain, and paralysis. In a recent paper published in Canadian Medical Association Journal, three Manitoba-based researchers have added to that list atrioventricular block: a slowing of the heart that can lead to cardiac death.

The paper highlights the case of Samuel Brandt, a healthy 37-year-old Manitoban man who presented at a walk-in clinic in July 2018 complaining of heart palpitations and chest pain. He died two days later. Three weeks earlier, he had had severe symptoms of a cold and the telltale bullseye rash. The autopsy revealed that the Lyme bacteria had attacked his heart tissue.

Richard Rusk, a Medical Officer of Health for communicable disease in Manitoba and one the report’s authors, feels that overall awareness of Lyme disease in Canada is lacking. Since it began tracking the disease in 2009, the Public Health Agency of Canada has seen more than a 14-fold increase in the number of cases, but Rusk feels that many still go unreported.

Rusk’s advice to Canadians is simple: prevention is the best cure. From spring through fall, anyone spending time in wooded areas that are home to the blacklegged tick should take sensible precautions, do a thorough check at the end of the day, and seek immediate medical attention if they find a tick. “The trick is not to wait,” he says.

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