Lone Star Tick Meat Allergy

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It’s enough to strike fear into the hearts of even the most casual steak lover.

While ticks carry a whole host of diseases with them — including debilitating Lyme disease — there’s another side effect that’s spreading: meat allergies.

What causes meat allergies?

A sugar molecule known as Alpha-Gal — short for galactose-alpha-1, 3-galactose — causes meat allergies in those who have it and is spread primarily by the Lone Star Tick.

"You're walking through the woods, and that tick has had a meal of cow blood or mammal blood," Cosby Stone, an allergy and immunology fellow at Vanderbilt University, told National Geographic. "The tick, carrying Alpha-Gal, bites you and activates your allergy immune system."


The body responds by creating antibodies that fight Alpha-Gal molecules. Sounds good, until you realize that meat is full of the molecules.

The allergic reactions are often delayed, meaning you won’t realize there’s a problem until hours later. "It [the Alpha-Gal] has to first travel through your gastrointestinal tract to be released,” Stone told the magazine. "Hours later, patients wake up with hives, shortness of breath, vomiting, and diarrhea."

"Some patients have had to be given life support because their blood pressure is so low that they're in imminent danger of dying," he added.

Where does Alpha-Gal come from?

University of Virginia allergy researcher Thomas Platts-Mills started studying Alpha-Gal in 2002 after some people — primarily in the southeastern U.S. — showed an unusual reaction to the cancer drug cetuximab, which contains the same Alpha-Gal molecules as meat. Oddly, other people without cancer in the same region reported meat allergies.

Platts-Mills didn’t connect the dots between meat and Alpha-Gal until he developed the allergy himself after being bitten by ticks. He studied the connection and confirmed the link in a 2011 study. However, he’s still not sure why some people develop the allergy and others don’t.

"We’ve thought of lots of possibilities, but haven’t identified specific traits yet," he said in a recent interview with UVA Today. "It’s clear that ticks bite some people and not others, but we don’t know why. You can take four people on a picnic in the grass and two of them will get covered in ticks and the other two won’t get any bites at all. We believe that might have something to do with how their skin smells to ticks."

Ticks are sensitive to smell in order to find a host, but many are only attracted to certain types of species. Some ticks — like those that carry Lyme disease — are only attracted to mice. The Lone Star tick is attracted to deer, according to Platts-Mills. The deer population is up, meaning the number of Alpha-Gal cases have also spiked in recent years.

The Lone Star tick isn’t the only one to blame for this allergy, though.

"We know of other ticks that can do this," Platts-Mill told UVA Today. “The Lone Star tick is Amblyomma americanum. In Australia, Ixodes holocyclus does this; in Europe, Ixodes ricinus does this; and we know of varieties in Japan and Africa that can do this as well," along with ticks in Europe and Australia.

It’s most common in adults, but "it definitely occurs in children," he said. "We’ve seen about 45 cases of it in children in our clinic and if they get tick bites, they can get it. It’s possible that children don’t get it as much, but we don’t have any hard evidence to prove that right now."

How to protect yourself against tick bites

Prevention is the best way to protect yourself against tick bites and meat allergies. The U.S. Centers for Disease Control recommends staying away from areas that are known tick havens, like tall grass, weeds and forests. If you do have to venture into these areas, make sure you spray on insect repellents approved by the Environmental Protection Agency that are formulated with DEET, picaridin, Oil of Lemon Eucalyptus, IR3535 or 2-undecanone. Clothing should be treated with products containing permethrin.

And if you do get bitten? It’s probably best to lay off the steak and BBQ for a while, no matter how difficult it seems.

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