Oh, Lovely: The Tick That Gives People Meat Allergies Is Spreading

Megan Molteni
June 17, 2017

First comes the unscratchable itching, and the angry blossoming of hives. Then stomach cramping, and—for the unluckiest few—difficulty breathing, passing out, and even death. In the last decade and a half, thousands of previously protein-loving Americans have developed a dangerous allergy to meat. And they all have one thing in common: the lone star tick.

Red meat, you might be surprised to know, isn’t totally sugar-free. It contains a few protein-linked saccharides, including one called galactose-alpha-1,3-galactose, or alpha-gal, for short. More and more people are learning this the hard way, when they suddenly develop a life-threatening allergy to that pesky sugar molecule after a tick bite.

Yep, one bite from the lone star tick—which gets its name from the Texas-shaped splash of white on its back—is enough to reprogram your immune system to forever reject even the smallest nibble of perfectly crisped bacon. For years, physicians and researchers only reported the allergy in places the lone star tick calls home, namely the southeastern United States. But recently it’s started to spread. The newest hot spots? Duluth, Minnesota, Hanover, New Hampshire, and the eastern tip of Long Island, where at least 100 cases have been reported in the last year. Scientists are racing to trace its spread, to understand if the lone star tick is expanding into new territories, or if other species of ticks are now causing the allergy.

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This time, it wasn’t a plate of pork chops they shared; it was a new cancer drug called cetuximab. The drug worked, but curiously, patients that lived in the southeast were 10 times as likely to report side effects of itching, swelling, and a dangerous drop in blood pressure.

Platts-Mills teamed up with cetuximab’s distributor, Bristol-Myers Squibb, and began comparing patient blood samples. He discovered that all the patients who experienced an allergic reaction had pre-existing antibodies to alpha-gal, and cetuximab was full of the stuff, thanks to the genetically modified mice from which it was derived.

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as far as anyone can tell, alpha-gal syndrome seems to be the only allergy that affects all people, regardless of genetic makeup. “There’s something really special about this tick,” says Jeff Wilson, an asthma, allergy, and immunology fellow in Platts-Mills’ group. Usually a mix of genes and environmental factors combine to create allergies. But when it comes to the lone star tick it doesn’t matter if you’re predisposed or not. “Just a few bites and you can render anyone really, really allergic,” he says.

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As for a cure? There’s not much science has to offer on that front, besides Epipens and veggie burgers.