The Ticks That Cause Red-Meat Allergies Are Spreading Across the U.S.
Lone star ticks, which can trigger alpha-gal syndrome—a red-meat allergy—are expanding their range across the U.S., particularly in the Midwest and Northeast, driven by warmer temperatures. Cases of the allergy, which causes delayed reactions to mammalian meat, are rising as tick populations grow and spread into new regions this summer.
Background
- Alpha-gal syndrome (AGS) is a red-meat allergy triggered by a sugar molecule (galactose-alpha-1,3-galactose) carried by lone star ticks. Unlike typical food allergies, it causes delayed reactions (2–6 hours after eating meat), including hives, stomach cramps, and potentially life-threatening anaphylaxis.
- The lone star tick (Amblyomma americanum), named for the white dot on its back, was historically concentrated in the southeastern U.S. but is now established as far north as New England and the Upper Midwest, driven by warming winters and growing deer populations.
- AGS was first identified by researchers at the University of Virginia around 2009; reported cases have since surged into the hundreds of thousands in the U.S., though many go undiagnosed because the delayed reaction and non-typical symptoms confuse doctors.
- Unlike Lyme disease (spread by deer ticks), there is no treatment or vaccine for alpha-gal syndrome; management requires strict avoidance of mammalian meat (beef, pork, lamb, venison) and sometimes dairy or gelatin-based products.