Tracking ticks: New study forecasts spread of Lyme disease in Eastern Canada
St. F.X. professor says we need to shift focus from elimination to prevention
If you live in an area that hasn't encountered blacklegged ticks, don't get too comfortable. While the ticks that carry Lyme disease bacteria aren't prevalent across all of Eastern Canada yet, new research says they soon will be.
Even under "optimistic" scenarios, ticks carrying Lyme disease could spread to all of Nova Scotia by 2040 and as far away as Newfoundland and northern Ontario by 2070, according to a study from St. Francis Xavier University.
It's not a rosy picture for a province already battling the impacts of the disease. But it's a message health policy makers need to understand and act on, says Dr. Hugo Beltrami, Canada Research Chair in Climate Dynamics,
"We need to look for a more permanent solution because eliminating the tick is just not realistic," Beltrami told CBC's Information Morning.
Climate change makes spread inevitable
A team of graduate students led by Beltrami used climate change data to map where the heat-loving ticks would go, depending on increases in temperature. What they found is the spread of Lyme is inevitable, even if the Paris Climate Agreement goal of limiting the rise of global temperatures is met.
"The issue is that there's enough climate change in the pipes, so to speak … at least for the tick population to expand," said Beltrami.
Their study was published in a journal called Environmental Health Perspectives last week. It uses tick population data collected by researchers in Ontario and climate simulations from the Intergovernmental Panel on Climate Change Report to project the population and path of infected ticks.
The study uses climate change models because Lyme disease is a "climate-sensitive infectious disease," meaning it gets worse in warmer temperatures.
Researchers ended up with 64 possibilities that are represented in maps that predict the spread from 2011-2040 and 2041-2070.
According to the map, the ticks carrying the disease will have spread into northern Ontario and to Newfoundland by 2070.
"We wanted to explore the likelihood of the expansion and the range of expansion and the number of ticks, that will start changing as we move on the future climate scenarios," said Beltrami.
"We wanted to know that because it's a lot easier to prevent the disease than cure it once it's already established."
Planning for prevention
Nova Scotia's Department of Health and Wellness has a map on its website that shows low-, moderate- and high-risk areas in Nova Scotia. Six counties are high-risk, including the municipality of Lunenburg and Yarmouth and Pictou counties.
Elaine Holmes, director of communicable disease prevention and control, said blacklegged ticks are "part of our ecology," because of the suitable habitat and number of hosts such as deer.
But the province is doing its part to spread the message about prevention, she said. The best defence is still not getting bit. That means tucking pants into socks, wearing enclosed shoes and bug repellent and doing tick checks, she said.
"The messages are out there and they're out there broadly and we're hoping Nova Scotians are listening to them," said Holmes.
An issue for doctors, too
Beltrami says physicians need to listen too.
He lives in Antigonish, N.S., which is a moderate-risk area. He says he's been bitten by ticks, but doctors simply removed them and sent him on his way.
"Public health measures should be taken now to educate physicians in the treatment of the disease at an early stage rather than have to deal with the consequences," he said.
With files from CBC's Information Morning