A Tick Is Making Farmers Allergic to Their Own Animals

When Clark Giles first heard about ticks making people allergic to meat, he found the notion so unbelievable, he considered it “hogwash.” Then, in 2022, it happened to him. Following a spate of tick bites, he ate a hamburger and went into sudden anaphylaxis. His lips became numb, his face swollen, and his skin a “red carpet from my knees to my shoulders,” he says. Eventually, Giles—who raises sheep on a homestead in Oklahoma—had to give up eating not just beef but pork, and, yes, even lamb.

From there, his allergy started to manifest in stranger ways. During lambing season, the smell of afterbirth left him with days of brain fog, fatigue, and joint aches. To touch his sheep, he now needs nitrile gloves. To shovel their manure, he now needs a respirator. And Giles doesn’t even have it the worst of people he knows: A friend with the same allergy was getting so sick, he had to give up his sheep altogether.

This unusual allergy is most often caused by the lone-star tick, whose saliva triggers an immune reaction against a molecule, alpha-gal, found in most mammals besides humans. The allergy is also known as alpha-gal syndrome, or AGS. In recent years, the lone-star tick has been creeping northward and westward from its historical range, in the southeastern United States. (Oklahoma is in fact right on the edge; ticks are more prevalent in its east than its west.) Alpha-gal syndrome, too, is suspected to be on the rise. Farmers who spend their days outdoors are particularly exposed to lone-star ticks, and repeated bites may cause more severe reactions. And so, Giles is among a group of farmers who have become, ironically, allergic to the animals that they raise.

There are no official numbers for how many farmers are afflicted with alpha-gal syndrome. But AGS has become prevalent enough, says Charles Green, Virginia’s deputy commissioner of agriculture, that the state farm bureau’s upcoming annual convention is offering an alpha-gal-safe meal option. Green himself developed the allergy after getting tick bites on his family farm. And he isn’t even the only ag commissioner I’ve interviewed with the condition: A couple of years ago, I spoke with the commissioner in North Carolina, a top hog-producing state, who could no longer, as his job usually requires, “eat more barbecue than any human being on the face of the Earth.”

For most people with AGS, just avoiding the meat from mammals is enough. But for those who are more sensitive, anything of mammalian origin is off the table: dairy, wool, gelatin, lanolin, and even more obscure products such as magnesium stearate, a fat derivative often found in pills and drug capsules. And for farmers like Giles, who are extremely sensitive, even the fumes from manure, dander, and amniotic fluid can set off reactions. “It’s so much more far-reaching than just, Don’t eat this. It’s, Don’t touch it. Don’t work with it. Don’t be around it,” says Jenna Olcott, who is no longer able to help out on her family’s small cattle farm in Missouri. Farmers with severe AGS find it difficult, and in some cases impossible, to care for their animals at all.

Sonya Bowes has lost count of the number of tick bites she’s gotten on her tiny farm in rural Kentucky. They’re hard to avoid, she says, when taking care of grazing animals in tall grass. She knew something was wrong when she started experiencing mysterious symptoms around her dairy cows, such as sudden drops in her blood pressure, that turned out to be signs of an allergic reaction. She can no longer milk them without getting sick. When we spoke last week, she had already sold her three cows as well as her rabbits. She’s planning to sell her pigs too, at a probable financial loss, because she cannot care for them anymore. Bowes’s small farm has been her livelihood and her lifelong dream. “It’s just been devastating” to give up on that dream.

Antonia Florence and her husband downsized their cattle farm in Virginia after their allergic reactions became so severe, they lost a calf because they were unable to physically help in the birthing process. “We had to stand back and ask ourselves, ‘Did that calf die because we could not care for it?’” she says. “It wasn’t ethical.” Amniotic fluid from cows is known to contain alpha-gal, and anecdotally, it seems to be a strong trigger of AGS. It is also, however, sometimes simply unavoidable; when a calf gets stuck during birth, a farmer may have to get up to their shoulders inside the mother to help. When Olcott helped her husband pull a stuck calf, she told me, everywhere the fluid splattered on her skin became swollen and red, as if she had been scorched. A case study in Spain has also documented three cattle workers who reacted to touching or even breathing amniotic fluid.

A second factor in the Florences’ decision was that their cattle were also becoming ill—with a different tick-borne illness called theileriosis. This bovine parasite does not affect humans, but managing it requires farmers to get up close with their cattle, which Florence and her husband could no longer do. Together, she told me, these two tick-borne illnesses are killing their farm. Raising cattle isn’t their only source of income, but the couple had put “every evening, every weekend, and every holiday” into the endeavor. Her husband also grew up on this farm, and some of the animals they raised even traced their lineage back to his grandfather’s cows. Unable to fully give up the animals, he still keeps about 10 cattle, but no more mothers or calves. Florence worries about the toll on his health, getting exposed to animals he’s allergic to all the time. He needed a pacemaker recently, and she wonders if it is related to an increased risk of heart disease with AGS.

Alpha-gal syndrome is forcing affected farmers to ask existential questions—not just about their identity as a farmer but about even the long-term viability of their industry. AGS is still unusual enough that it is likely to be underdiagnosed; a survey published in 2023 found that 42 percent of health-care providers had never heard of the syndrome. But as lone-star ticks continue to spread across the country, more and more Americans may eventually find themselves unable to eat beef and pork. (Of course, those opposed to eating animals on ethical and environmental grounds might find cosmic justice in the spread of alpha-gal syndrome. A bioethicist, inspired by the lone-star tick, once proposed decreasing the world’s red-meat consumption by inducing a human immune intolerance to it.)

A few farmers I spoke with have considered switching to raising poultry for other people with AGS, including chicken as well as more exotic species, such as emu and ostrich. The big, flightless birds have red meat that bears a striking resemblance to beef, and they’ve gained popularity in the AGS community. Olcott, in fact, is raising these birds for herself on her family’s cattle farm. They’ve butchered and eaten an ostrich already—“I don’t taste any difference between it and beef”—and still have four emus. She jokes to her husband about switching the whole farm to emus and ostriches, as more sustainable sources of red meat. He isn’t sold yet. But he is much more careful about ticks these days.