Ticked Off Meat Eaters

The warm weather brings out two things: barbeque and ticks. But how are the two related? That's what interesting; a person bitten by a lone star tick can develop a severe allergy to meat. We knew about Lyme disease, but meat allergy?!

This happens because some people bitten by the tick develop antibodies against a complex sugar called galactose-alpha-1,3-galactose, also known as alpha-gal. Alpha-gal is in all non-primate derived proteins, which means it's in pork, beef, and lamb.

The main symptom is a hive-like rash, but some people develop life threatening anaphylactic shock. It takes four to six hours after eating meat for symptoms to show, so people don't associate their rash with meat.

The allergy to alpha-gal was first discovered among cancer patients with an unusual sensitivity to the cancer drug cetuximab which also includes the alpha-gal molecule. These patients were almost exclusively from the southeastern US, where the lone star tick lives.

It's still unclear what in tick saliva triggers this response. Ticks can latch to its host for days and transmit a variety of pathogens including viruses and bacteria. But tick saliva also contains molecules that influence a host's blood coagulation, immune response, and angiogenesis which is the development of new blood vessels.

For all of us who love barbeque, the only way to avoid developing a meat allergy is to avoid tick bites. The downside is that the lone star tick's territory may be continually expanding, but evidence suggests the allergy eventually goes away - as long as you don't get any more tick bites!