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Why Canada Markets Permethrin-Treated Clothes For Ridding Mosquitoes, Not Ticks

Jun 25th 2018

Whenever Jim Rosbe works in his yard, he first suits up from head to toe. The Indian Point, N.S., man wears special anti-tick clothing he ordered from the U.S. because until recently, it wasn't available in Canada.

Rosbe calls it self-defence against black-legged ticks, which can carry the bacteria that causes Lyme disease. He's had Lyme disease twice.

Earlier this year, permethrin-treated clothing was approved in Canada, but Health Canada only allows it to be marketed to keep away mosquitoes — not ticks — even though it's essentially the same product Rosbe can easily get south of the border.

"It doesn't make any sense," Rosbe said. "I would think there'd be a common body of science that they could draw on without having to reinvent any wheels or go through a whole lot of rigamarole."

Mark's Work Wearhouse is the company that got approval from Health Canada to sell a brand of permethrin-treated clothing from North Carolina. But Iain Summers, vice president of innovation with the company, told CBC News it took a decade to make that happen.

Does permethrin work?

Permethrin is a synthetic insecticide that can be used as a spray on clothing or infused directly into clothing.

When a tick comes into contact, it's "essentially stunned" and falls off, said Brian Patton, co-author of the Canadian Rockies Trail Guide.

He's long been calling for greater access to the insecticide in Canada.

"The important thing about permethrin is that once it's dried into clothing via the processes that these various companies use, it is totally safe, but it's very effective against killing and stunning any kind of insect that gets onto it," Patton said.

A recent study in the Journal of Medical Entomology found that permethrin does deter black-legged ticks, and the researchers concluded it was a promising way to tackle Lyme disease.

Health Canada recommends it

Although permethrin hasn't been widely sold to consumers in Canada, it's been approved for other uses for years, including in military outerwear and for livestock.

According to Health Canada, it "may pose a risk to aquatic organisms, bees, beneficial insects and birds."

Patton, said the federal government seems to agree with him and Rosbe. It even suggests travellers use permethrin when they're going to areas with high cases of tick-borne illnesses.

"Permethrin is known to repel and kill a variety of arthropod or insects and permethrin would be a [welcome] addition to the tool box for repelling ticks," said Robbin Lindsay with the Public Health Agency of Canada in a written statement to CBC News. 

The problem, said Lindsay, is that Mark's Work Wearhouse didn't prove it works on ticks.

"It has been demonstrated to effectively repel ticks in many different studies but it is not currently registered for that use pattern in Canada," he wrote. 

Spreading the word about permethrin 

Summers said the company is in the process of submitting another application to get approval for ticks, but he admitted they still don't know what Health Canada wants. 

Rosbe said it's strange not to have ready access to permethrin in Canada when he sees it widely available in the U.S., including recently at an airport.

The coveralls, shirts, pants, socks and hat that Rosbe purchased need to be replaced after roughly 70 washes, he said.

Rosbe's wife also has anti-tick clothing and he's been telling his neighbours about it.

Rosbe said he hasn't had a tick bite since 2016.

"I would think it would be appropriate to expedite any process given that it's effectively a public health emergency," he said.

Story re-posted from CBC News. Written by Emma Smith

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