Health

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

Attack by a lone star tick is difficult to diagnose because symptoms do not appear immediately

Les Waters

Les Waters doesn't know where a lone star tick bit him, but the dedicated hunter knows the bite caused a severe allergy that prevents him from eating his beloved red meat. (Marcy Cuttler/CBC)

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Les Waters will never forget his reaction after 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 hunter and meat lover, learned he had developed a rare allergy to everything made from beef, pork and lamb.

A bite from a tiny tick, recently spotted in Canada, is to blame.

The culprit, the lone 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 says the 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.

Tick Meat Allergy

The lone star tick, which is moving from the southeastern United States into Canada, is named for the white dot on the back of the female. (James Gathany/Centers for Disease Control/Associated Press)

How these ticks cause the allergy that affects Waters, which was first identified in the 1990s, is complicated.

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

That's a compound present in beef, pork and lamb, and humans usually digest it harmlessly. But when it appears elsewhere in a 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 severe anaphylactic 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't appear 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 is identifying Canadian locations 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.

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