Experts predict a bad year for ticks as disease-carrying insects expand in Canada

Lindsey Armstrong, The Canadian Press

Date: June 1, 2022 5:54AM EST

The prevalence of ticks that can carry Lyme disease is expected to be higher than ever in most of Canada this year, researchers said.

As the effects of climate change progress, each tick season is likely to be worse than the last, says Phet Lloyd, researcher and director of the Lloyd Tick Lab at Mount Allison University in New Brunswick.

“As winters get milder and shorter, ticks live better, have more time to feed and have a romance,” Lloyd said in a recent interview on Friday. Once a female tick finds a male and food, she can produce approximately 3,000 eggs. When this starts to happen, it (the population) explodes very quickly.”

Lloyd said Nova Scotia has the highest tick-to-people ratio in Canada, second only to Ontario in the total number of ticks reported. But insects can be found all over Canada.

People will notice ticks, perhaps on their pets or in their hair, after spending time outside near tall grass. They are active in late April through June, then usually rest during the hotter months, Lloyd said. The sign’s presence peaks in late September through November.

This small bug is a concern because it spreads Lyme disease that is harmful to humans and pets. Not all ticks carry Lyme disease bacteria, Lloyd said, but black-legged deer ticks are more likely to become infected.

Cases of the tick-borne disease in Canada increased 150 percent between 2020 and 2021, with nearly 2,900 cases reported to the federal government last year. The report notes that the Lyme case toll may still be low, “because some cases have not been detected or reported.”

The most common sign of Lyme disease is an expanding rash that usually begins at the site of the tick bite. Other early symptoms include fever, chills, fatigue, and headache. If left untreated, the infection can spread to the joints, heart, and nervous system.

Justin Wood, chief executive of Ontario-based tick-testing organization Geneticks, said tick activity continues to rise. “I think everyone would say they see more ticks every year,” Wood said in an interview on Tuesday. He said the Geneticks lab has received more than 400 ticks for testing in the past six weeks. About 1,600 ticks were sent to the lab throughout the 2021 season.

“It’s a bad year for ticks,” Lloyd agreed.

Ticks can breed locally, Lloyd said, and new populations of ticks are introduced to migratory animals, usually by riding birds. Ticks also transmit and spread locally on mammals such as deer or mice.

The Canadian Veterinary Medical Association says on its website that ticks are expanding their range in parts of Canada at a rate of about 46 kilometers per year.

In Ontario, a 2019 University of Ottawa study found that a third of the black-legged ticks in the Ottawa region carried Lyme disease.

Over the past five to 10 years, researchers have observed a “significant northward expansion” of black-legged ticks in the Ottawa region, Manisha Kulkarni, an associate professor at the University of Ottawa who studies ticks and tick-borne diseases, said in an interview.

“Ticks are being detected in more and more locations around Ottawa and closer to the areas where people live, so there is also a greater chance of communicating with them,” she said on Tuesday. The city of Ottawa reported 180 cases of Lyme disease in 2019, 120 in 2020, and 290 in 2021.

Northward expansion of the tick is also observed in Quebec. Virginie Millen, a professor of biology at McGill University, says the movement of ticks means they can now be found in suburban areas in the southern part of the county where they didn’t live even five years ago.

About 10 years ago, there were a few sites in Quebec where researchers could find steady populations of ticks, she said, all on the south side of the Saint Lawrence River.

“They have crossed the river now, the warmer it gets and the more moisture … the conditions are perfect for ticks,” Milian said Monday. “In southern Quebec, they are now pretty much everywhere. Including in my backyard.”

In Nova Scotia, a tick can be anywhere, but it is more populated in the South Shore and Annapolis Valley regions. They are also frequently found in Halifax and surrounding areas. Researchers who collected and sampled black-legged ticks found that 30 to 50 percent of them in Nova Scotia carry Lyme disease.

In order to keep Lyme disease manageable for Canadians who may become infected, Lloyd would like to see extensive Lyme disease testing available in the health system. She said early detection and treatment can significantly improve disease outcomes.

Health officials are also advising people to spend time outdoors, which means wearing long pants tucked into socks, using insect repellent, and checking thoroughly for ticks after returning home.

This report was first published by The Canadian Press on June 1, 2022.

This story was produced with financial assistance from the Meta Fellowship and Canadian Press News.

2022-06-01 09:54:51

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