How can a bug bite make you allergic to meat?

We usually think of food allergies as something we’re born with. Sometimes we develop them later in life, but for the most part, there’s not really anything we can do to cause them.

Except get bitten by ticks.

A certain kind of tick, at least. The lone star tick, found in the eastern half of the U.S. and Mexico, can cause you to develop an alpha-gal allergy. Alpha-gal is a sugar found in red meats like beef, lamb and pork. Lone star tick bites, it seems, increase the level of antibodies for alpha-gal in your body, leading to allergic reactions when you consume red meat.

Other animal products have been reportedly associated with the disease. In its recounting of how the phenomenon came into scientific understanding, Mosaic Science interviewed one bite victim who can no longer enjoy cheese, gelatin or even wear wool clothing. The allergy can even complicate unrelated medical treatments, like the use of vaccines with bovine ingredients or getting replacement heart valves, which are sometimes grown in pigs.

The allergic reactions can be minor, but anaphylactic shock can also occur. There’s good news, though — the allergies tend to disappear in three to five years, provided the victim isn’t bitten again.

Gaining ground

The lone star tick is different from the black-legged tick, which is infamous for being a primary carrier of Lyme disease. But the lone star tick is gaining more ground than its more well-known counterpart.

“The northern edge of where these ticks are abundant is moving,” Dr. Richard Ostfeld told Mosaic. “It is now well-established further north, into Michigan, Pennsylvania, New York and well up into New England.” Ostfeld suggests that climate change may play a role in the spread.