It’s any barbecue-lover’s worst nightmare: You go to bed after enjoying a juicy burger or a smoky rack of ribs, only to awaken, covered in sweat and hives. You’ve become allergic to meat. An increasing number of meat lovers in the United States and around the world have had this horrific experience in recent years, and it’s all because of a tiny parasite.
The culprit, the Lone Star Tick, spreads this potentially life-threatening allergy through its bites. Researchers don’t know exactly how the tick spreads the allergy, but they have identified which component of meat causes the allergic reaction. Mammal meat — pork and beef — contains a sugar called galactose-alpha-1,3-galactose (alpha-gal for short), and in people with the allergy, alpha-gal triggers an immune response that includes a massive release of histamines, much like your body would respond to other allergies.
Wired reported that in 2004, University of Virginia immunologist Thomas Platts-Mills, Ph.D., identified the alpha-gal connection after examining blood work from people that experienced strange reactions not to meat but to a cancer drug called cetuximab. People in the southeastern U.S., they found, were 10 times more likely to be allergic to this effective cancer drug. Further investigation showed that the region was also home to people with meat allergies. Since cetuximab and mammal meat both contain alpha-gal, and the affected people’s blood contained alpha-gal antibodies, the researchers hypothesized that the sugar was behind the allergy.
Most scientists agree that allergies occur when a foreign allergen — like alpha-gal — is mistakenly marked as an invader by the antibodies of the body’s immune system, which then releases chemical weapons to destroy it. One of those weapons is histamine, which triggers the inflammation necessary to deal with the allergen — but also causes the rest of your body to swell up, as well.
Since cases of Rocky Mountain Spotted Fever, which is spread by the Lone Star Tick, also arise in the same southeastern region, researchers are pretty sure that it’s the tick bites that are causing the allergies to meat and cetuximab. While the details of the allergy-spreading mechanism have yet to be understood, they’re likely involved in priming the body’s immune system to react badly to alpha-gal invasions.
As far as scientists know, this condition is lifelong. Unfortunately, the reaction is life-threatening, too, as anaphylaxis can cause a person’s airway to swell shut.
These cases have previously occurred mostly in the southern, southeastern, and central U.S., reports of new meat allergies have surfaced in the northeast, including Pennsylvania and New York. It’s unclear whether this means that the tick’s range is spreading or whether the ability to confer this allergy has spread to other tick species.
If you want to avoid developing this allergy, take basic precautions when going out in the woods or high grass. Check yourself thoroughly when you get home, especially in your body’s folds and near waistbands or elastic parts of clothes. And if you experience sweating, itching, or difficulty breathing a few hours after you eat meat, seek immediate medical attention.