One bite from this tick could ruin red meat for life

Who doesn't love a juicy burger? About 5,000 Americans. And not from dietary preference, but because a single bite could cause hives, shortness of breath, or even death. It's not something they were born with, it's something their body was taught to reject, by an uninvited little wilderness hitchhiker. The following is a transcript of the video.

Imagine that you're a red-blooded carnivore. You love burgers, steak, pork chops, bacon. But one day, out of nowhere, red meat starts to make you physically sick to the stomach. It sounds like science fiction, but it's real, and it's spreading.

It's spreading to people like Amy.

Amy Pearl: My name is Amy Pearl, and I'm a producer for WNYC.

She has what is called a mammalian meat allergy.

Amy Pearl: I have a tendency to not mention it at restaurants, because I feel like if you say to a server, I'm allergic to meat, they're gonna be like, I'm spitting in your food.

Any meat that came from a cow, a pig, or a lamb, will make Amy sick. Very, very sick.

Amy Pearl: Like I just had hives on my hands and my feet, and like all over my torso. I was nauseous, and I felt like I was fainting, I felt like the world was ending, I felt like I was gonna pass out and I couldn't really breathe.

Thousands of Americans are suffering like Amy, but until 2009, this sort of allergy went undiagnosed.

Amy Pearl: I think I made an appointment with my regular physician, but he immediately was like, there's no such thing as a meat allergy, has to be something else.

That changed with the cancer drug, Cetuximab. In a clinical trial, one in four patients developed severe allergic reactions to the drug. Some even died.

Naturally, Cetuximab was investigated. University of Virginia's allergy department focused on one specific part of the drug. The key ingredient in Cetuximab is a specific carbohydrate that all non-primate mammals carry in their cell walls and tissues, Galactose-alpha-1,3-galactose, or, if you're pressed for time, alpha-gal.

Dogs have it, cats have it, and the mice cells involved in the production of Cetuximab have alpha-gal. The team discovered that those who had reactions were from only certain areas of the US, the southeast. The locations of the cases aligned almost perfectly with the range of a specific type of tick, the lone star tick.

Dr. Scott Commins is an allergist, and was working with the University at the time.

Scott Commins: Over 90 to 93% of our patients that developed allergic reactions to red meat and test positive by blood test will have a history of tick bites.

Amy Pearl: The thing I Googled was "sudden meat allergy." I found an article that said there was some man in Florida, had gone into anaphylactic shock from eating meat after a tick bite. And I was like, "I had a tick bite!" I mean, I often have a tick bite. I'd just taken a tick off me.

One of the leading researchers, Dr. Thomas Platts-Mills, went so far to use himself in an unofficial experiment, taking a hike through a nest of larval ticks. It earned him a nice case of red meat allergy.

There's still a lot we don't know about how this meat allergy works, but here is the leading theory. Ticks don't have alpha-gal naturally, but they could be carrying it if they fed off a mammal, like a deer or a dog. If a tick then bites you, it trades some of your delicious blood for its saliva, which is a cocktail of nasty things. An enzyme in that saliva tells your body that there's a variety of dangerous threats, and your immune system bans everything in that saliva from entering the body, including alpha-gal, which is also in every burger, steak, and bacon strip. So the next time you eat one of those, your body treats the carbohydrate like an intruder, and hits the panic button.

This is happening in the bodies of an estimated 5,000 Americans. What's worse is that the range of the lone star tick is growing.

Scott: Their range is spreading into the Ohio River Valley and now up into Minnesota. We also know places where this alpha-gal red meat allergy exists, but they don't have lone star ticks at all. And this would be southern Sweden, for example, there's parts of Europe, Australia, and now even South Africa. So clearly other tick species can do this as well.

University of Virginia's researchers have also linked the alpha-gal allergies with a higher risk of heart disease.

Scott Commins: This allergy seems as though it will often go away over time, but the problem has been that any additional tick bites seem to cause the allergy to return. And these are often patients who like to be outside.

Amy Pearl: I know that my numbers have gone down, because I've been retested a couple of times, but they're still 10, 20 times what they should be.

Dr. Commins continues to work towards an immediate cure to mammalian meat allergy. In the meantime, the number of cases are rising.

Scott Commins: So what we've been trying to do is work on a vaccine related to tick saliva, in hopes that we can prevent the allergic response from continuing, or recurring, with additional tick bites.

If you've been bitten by ticks recently, be sure to get tested. If you haven't, learn how to explore the woods safely.

Scott Commins: you may want to consider pre-treating your skin or clothing with DEET or Permethrin, respectively.

Amy Pearl: People are so freaked out about ticks, it's not that bad. They're much easier to see than you think.

Learn how to do a tick check after spending time in the wilderness. And if you value a juicy steak over a walk in nature, then maybe stay out of the woods.