Why are so many people getting a meat allergy?

It is early morning in early summer, and I am tracing my way through the woods of central North Carolina, steering cautiously around S-curves and braking hard when what looks like a small rise turns into a narrow bridge. I am on my way to meet Tami McGraw, who lives with her husband and the youngest of their kids in a sprawling development of old trees and wide lawns just south of Chapel Hill. Before I reach her, McGraw emails. She wants to feed me when I get there:

“Would you like to try emu?” she asks. “Or perhaps some duck?”

These are not normal breakfast offerings. But for years, nothing about McGraw’s life has been normal. She cannot eat beef or pork, or drink milk or eat cheese or snack on a gelatine-containing dessert without feeling her throat close and her blood pressure drop. Wearing a wool sweater raises hives on her skin; inhaling the fumes of bacon sizzling on a stove will knock her to the ground. Everywhere she goes, she carries an array of tablets that can beat back an allergy attack, and an auto-injecting EpiPen that can jolt her system out of anaphylactic shock.

McGraw is allergic to the meat of mammals and everything else that comes from them: dairy products, wool and fibre, gelatine from their hooves, char from their bones. This syndrome affects some thousands of people in the USA and an uncertain but likely larger number worldwide, and after a decade of research, scientists have begun to understand what causes it. It is created by the bite of a tick, picked up on a hike or brushed against in a garden, or hitchhiking on the fur of a pet that was roaming outside.

Reference:

• The discovery of alpha-gal allergy begins in 2007 with the recognition that cancer patients in a few locations are reacting badly to a new drug.
• A team at the University of Virginia realises that the reaction is associated with a sugar present in mammal muscle – and in one throwaway clause, mentions it might be related to ticks.
• Two years later, the team confidently declares that tick bites are “a cause, or possibly the only cause”, of the allergy to meat.
• Meanwhile, in Australia, another researcher has been pursuing the same problem since the 1980s.
• Researchers are now discovering that the ‘meat allergy’ might also be involved in reactions to personal care products, over-the-counter medicines, vaccines and heart valves – and might play a role in heart disease.