Aggressive tick whose bite makes people allergic to red meat is arriving in Canada

Les Waters will never forget his reactionafter he ate a hamburger at a restaurant in January 2015.

"It's like your throat swells up, you can't breathe, your blood pressure drops, and you black out," said the 63-year-old man from Harcourt, a small community in eastern Ontario.

Waters, an avid hunterand meat lover,learned he had developed a rare allergy to everythingmade from beef, porkand lamb.

A bite from a tiny tick, recentlyspottedin Canada,is to blame.

The culprit, thelone star tick, is named for the white dot or lone star on the back of the female. Native to the southeastern United States,it has slowly migrated north, hitching a ride on birds, deer, and domestic animals.

Waters is not sure where the tick found him, but he suspects it might have been on a hunting trip in northern Quebec. The lone star tick has been found in neighbouring New Brunswick.

"The two we have which were contributed to us by people in New Brunswick, one fed from a human and one fed from a dog," said Prof. Vett Lloyd, a biologist at Mount Allison University in Sackville, N.B.

Dr. Lloyd saysthe lone star tick, unlike other ticks, is aggressive. "It is one of the few that will actually chase their prey. Once they know that you're there, they will trundle towards you," she said.

How thesetickscause the allergy that affects Waters, which wasfirst identified in the 1990s,is complicated.

When the tick bites a person, it spits alpha gal into the blood.

That's a compoundpresent in beef, porkand lamb, and humans usuallydigest it harmlessly.But when it appears elsewhere ina person's body, for example in the bloodstream, it causes a strong reaction.

The body develops antibodies to fight back, and the battle causes symptoms that range from a general rash to a severeanaphylactic reaction.There is no treatment yet.

It took almost two years for Waters to get a diagnosis from an allergist, and much of the work was through his internet sleuthing.

Part of the problem is that the effects of this allergy, unlike food allergies, don'tappear immediately. "It comes hours after I eat something. They [the doctors]had no clue, basically. Now they know about it. Not all of them, but they're getting better at it,"he said.

'A novel allergy'

Dr. Gordon Sussman, an allergist in Toronto, says, "It's a novel allergy that sort of changes our concept because you can see reactions occurring several hours later. It's going to change the way we investigate allergies."

Lloyd says that while sightings of the lone star tick are rare in Canada, that might soon change.

"There's going to be more of them simply with climate change, with the environment warming. Ticks that were comfortable in the south are going to be more comfortable in the north," she said.

The Public Health Agency of Canada is aware that the lone star tick is expanding its range and isidentifying Canadianlocations that may soon fall within it.

A boring diet

As for Waters, who loves to hunt, there's an irony in developing this allergy. "I have all sorts of wild game in my freezer and I just have to give it away now. I'm just going to have to give this up," he says.

He carries an EpiPen now and avoids red meat, although the temptation is always there.

Waters calls the allergy "an annoyance."

Still for the diehard carnivore, it's a tough transition. "The taste of a good burger, a nice moose steak or some venison loin chops. You get very bored with the fish or the chicken over and over," he said.