Lyme disease may have a foothold in Toronto: Public Health

In all, teams from Toronto, York and Durham regions caught 11 of the ticks – which are the sole insect carriers of Lyme disease in Ontario, and not previously known to be an established species anywhere in Greater Toronto – by dragging flannel sheets over likely spots in and around Rouge Park.

"We think it’s a situation that’s evolving," said Dr. Howard Shapiro, an associate medical officer of health for the city.

He said the department will check the valley and other large Toronto green spaces for the ticks again next spring before it decides whether they have established themselves permanently in the city.

It was previously thought Torontonians who contracted Lyme disease without going to a place where blacklegged ticks are found – such as the Eastern Seaboard of U.S. and bird migration spots on Lake Erie and the St. Lawrence River – were bitten by ticks which had fallen off birds, but Shapiro said the insect’s range is expanding.

A Toronto Public Health release on Tuesday, Nov. 25 said the three health units investigated after residents of the city and surrounding regions reported the ticks in Rouge Park.

"No ticks were found during prior searches by the public health units. This new information suggests blacklegged ticks and Lyme disease are becoming established in the Rouge Valley," the release said.

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• Dec 31, 1969
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There were 26 reported cases last year in Toronto of Lyme disease, and just one was thought to have caught the disease inside the city.

"The risk is still very small. I’m not saying it’s going to stay like that," Shapiro said.

Lyme disease, which can produce symptoms including fever, headache, fatigue, muscle pains and a distinct red bull’s eye rash, can be treated early with antibiotics but, if untreated, can lead to a longer-term illness.

The department said anyone developing these symptoms after a tick bite should seek medical help.

In 2009, Mary Crover of Scarborough said her dog developed Lyme symptoms after walking that fall in the Rouge Valley and in Scarborough’s Morningside Park. She and her eight-year-old son later had symptoms too, convincing Crover veterinarians should be required to make pet owners aware when they may have been exposed.

Shapiro said it’s possible Crover and her dog were victims of the vanguard of a tick population getting established in the valley, "but we didn’t know it at the time."

The department said prompt removal of the ticks is important, as they require 24 hours to transmit the disease, and added owners should put flea collars on their pets and check them for ticks routinely.