Ticks Making People Allergic to Meat

Like most hunters who spend time in the spring woods, Jack Boyd never gave much thought to the ticks embedded in his skin at the end of the day. They were just part of the hunt. Boyd pulled them out, flushed them down the sink, and went about his day.

That changed in 2014. A college student at the time, Boyd threw a steak on the grill one evening as he studied for exams. A few hours later, he awoke to some of the most intense itching he had ever experienced.

“It started in my scalp,” he recalled. “Then it worked its way down my body. I got a rash all along my major veins and arteries, all the way down to my feet and hands. It felt like a severe sunburn under my skin. I finally fell asleep, and I was fine the next morning.”

When the same symptoms occurred a few weeks later, also after a steak dinner, Boyd became suspicious.

“A couple of guys at school had this allergy to red meat,” he said. “I never gave it much thought, but when I had a second reaction, I put two and two together and went to a doctor and got tested. I was always pulling ticks off me during turkey season, so I was pretty sure I had the same thing.”

The results came back positive. Boyd had an allergy known as alpha-gal, also known as the “red meat allergy.”

Never heard of it? You will. The technical name is galactose-alpha-1,3-galactose, a sugar present in all mammals except African and Asian primates and humans. Scientists call it alpha-gal. Although research has ramped up in recent years, the medical community still isn’t sure how the allergy develops after a tick bite—specifically bites from the Lone Star tick.

“One hypothesis is that a tick has to feed on a lower mammal first before injecting alpha-gal into a human. We think it somehow interrupts the immune system responsible for blocking the allergic reaction in some people,” said Dr. Scott Commins, University of North Carolina associate professor of medicine, who specializes in allergies, including alpha-gal.

Most food-related allergic reactions—peanuts, wheat, soy, for example—occur almost immediately after exposure to an allergen. Doctors still aren’t sure why that’s not the case with alpha-gal. Reactions typically don’t occur until three or four hours after meat is consumed. Commins thinks it may have to do with the metabolic process.

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“We think that the absorption of fat and the time that it takes for that to occur may explain the delay,” he said.

And that delay is exactly why it is so hard to diagnose in new patients.

“It is much easier to link an allergy to something like peanuts. You eat them and almost immediately have a reaction. That’s not the case with alpha-gal.”

However, as more people are diagnosed with the allergy, others are becoming more aware of the symptoms and causes. Boyd was diagnosed relatively quickly because of his college friends.

“I remembered hearing them talk about how they couldn’t eat certain types of meat and the reactions they got if they did,” he said. “That’s why I got tested.”

Not everyone who is bitten by a Lone Star tick develops the allergy. Those who are affected can experience different reactions, which vary from a mild rash and itching to intense itching and severe anaphylaxis. What’s more, some alpha-gal sufferers react not only to mammal meat, but also to anything that contains any mammal product: milk, butter, even the gelatin capsules of some medications. Boyd can eat pork and venison without a single issue.

“There are still a lot of unknowns,” said Commins. “We don’t know why some people have more severe reactions, for example, or why some people can eat certain types of mammal meat.”

For obvious reasons, hunters are especially at risk. Turkey hunters even more so because ticks are emerging from hibernation in the spring and are actively seeking food sources. Those that don’t feed die. So they wait patiently on the tip of a leaf or a blade of grass, front legs outstretched, and latch on to any blood-filled creature that comes by. Deer, quail, mice, turkey hunters, even snakes.

In some regions, upwards of 70 percent of blacklegged ticks carry Lyme disease, but researchers still don’t know how many Lone Star ticks may transmit alpha-gal. Nor do they know what percentage of the human population is susceptible to developing the allergy.

They do know the number of cases is growing rapidly.

So have numerous other tick-borne illnesses. Just 20 years ago, few people had ever heard of Lyme disease or Rocky Mountain spotted fever, and reported cases of both bacterial infections were relatively rare. Last year, an estimated 300,000 Americans contracted Lyme disease.

Part of that spike has to do with better reporting and a higher awareness by the medical community. Doctors today are more likely to test for various tick-related diseases. However, the increase also has to do with other factors, including the rapid spread of some tick species.

For example, the historic range of Lone Star ticks was primarily in the Southeast and north to New Jersey and the Ohio River Valley, according to a study published by the National Institutes of Health. That range now includes nearly all of New England and Pennsylvania. Lone Star ticks are even found in parts of Michigan. Blacklegged ticks, or deer ticks, which transmit Lyme disease, are also moving northward and are now established throughout most of southern Canada.

The reason?

In the International Journal of Environmental Research and Public Health, Dr. Daniel Sonenshine, Old Dominion University, writes, “Ticks have been expanding their geographic ranges in recent decades largely due to climate change.”

That may be part of it, but Dr. Thomas Mather, University of Rhode Island tick specialist, said it was likely that it has to do with a more visible phenomenon.

“There are more ticks in more places because there are more deer in more places,” he said. “Ticks need a host to survive, and deer are large hosts that can feed many, many ticks. The nymphs and larvae can be carried to new areas by birds, but once they drop off that bird, they need another host to feed on. We’ve seen an increase in the number of deer over the last 30 years or so and in the number of places they inhabit, so it only makes sense that tick-related illnesses have essentially followed those trends.”

Most tick-borne diseases—Lyme, RMSF, anaplasmosis, and ehrlichiosis, among others—are either viruses or bacteria transmitted through a bite. Specifically, they are passed within saliva as the tick pushes its feeding tube into a host’s skin. Various symptoms, including fever, fatigue, sore muscles and joints, and nausea, typically begin within a few days after being bit.

The good news is that it takes at least six hours for most bacterial infections to transmit from the tick to the human. Some can take up to 24 hours. Pull an embedded tick quickly and the risk of illness decreases dramatically. What’s more, those bacterial infections can be treated with a round of antibiotics if they are diagnosed quickly.

However, there is no treatment for viral infections like Bourbon, Powassan, and Heartland viruses. Nor is there any treatment for alpha-gal. The intensity of alpha-gal reactions can decrease over time in some victims, but it can take years for the allergy to disappear completely. Boyd, now a 25-year-old Virginia resident, takes a cocktail of Benadryl, Zantac, and Zyrtec when he experiences a reaction.

“We are researching treatments that can prevent the reactions, but they could be quite a ways off,” said Commins.

Commins and Mather agree that the best way to avoid coming down with alpha-gal or any other tick-related illness is to avoid getting bitten by ticks.

“The most effective thing you can do is wear clothing treated with permethrin,” said Mather. “You can either buy pretreated clothing like Insect Shield, or you can treat your clothes yourself with a permethrin-based spray like Sawyer insect repellent. Make sure you treat your boots and shoes, too. Ticks will grab on to the nearest thing they can. If it isn’t treated, they may find a way to your skin.”