Ticked-Off Carnivores

Ticks are icky. They spread Lyme disease. And now it appears they might interfere with your ability to enjoy a hamburger. A team headed by Dr. Thomas Platts-Mills, UVA professor and former president of the American Academy of Allergy, Asthma and Immunology, recently published findings that suggest that tick bites may cause allergic reactions to red meat. Dr. Platts-Mills says that tick saliva may trigger the human immune system to produce antibodies to a carbohydrate called alpha-gal, which is found in red meat.

Dr. Scott Commins, an assistant professor of medicine at UVA and lead author of the study, explains that an allergic reaction occurs when the body produces antibodies—meant to defend against harmful bacteria or toxins—against an otherwise benign substance, the allergen. When antibodies bind to the allergen, certain cells release histamine, which in turn causes symptoms such as swelling, hives and breathing problems.

The researchers screened hundreds of human blood samples from locations in the U.S., Africa and Central America for the antibodies against alpha-gal. Their findings? Meat allergies are more common in places where tick populations are on the rise. The team also studied people with the allergy in the laboratory setting. “We’re sure ticks can do this,” Dr. Platts-Mills told the Washington Post. “We’re not sure they’re the only cause.”

Unique to this particular allergy is that the reactions are delayed. Symptoms don’t appear until several hours after exposure, which can make them difficult to diagnose. “We have now performed this under observation, and there are no symptoms until after 3 to 4 hours,” said Dr. Commins. Dr. Platts-Mills and his colleagues’ next topics of study: Why are the allergic reactions so delayed? And why do only some people develop the problem?