The tick spreading a strange meat allergy across the U.S.

After taking a walk on her Missouri property in early 2024, Hannah Velier found a tick bite on the back of her knee. The wound looked ugly, but Velier said she didn’t worry too much. “My whole life we’ve dealt with ticks, not really ever thought twice about them,” she said.

Then, about a month later, Velier’s throat went numb and her lips swelled. That was followed by severe joint pain, difficulty breathing, stomach cramps, and low blood pressure. At a family member’s suggestion, Velier decided to get tested for alpha-gal syndrome, a disease that causes an allergy to mammal meat and by-products.

“I was 15 weeks pregnant, [and] my labs came back positive,” Velier said. “I was floored.”

Velier had to cut out all mammal-based products from her diet, including red meat, soaps with animal-derived glycerin, gelatin medicine capsules, water that passed through mammal bone filters, and even certain kinds of toilet paper. Her condition was likely caused by a bite from a lone star tick.

As lone star ticks have expanded their range across the United States, many Americans have developed alpha-gal syndrome. The condition has no known cure, though researchers note that many people bitten by lone star ticks never get severely sick, and some regain a tolerance for red meat over time. According to the Centers for Disease Control and Prevention, more than 110,000 suspected alpha-gal syndrome cases were reported between 2010 and 2022. As many as 450,000 U.S. residents may currently have the disease.

The alpha-gal molecule is abundant in red meat. The same molecule in the tick’s saliva can trigger an immune response in the bitten host, causing the person to develop an alpha-gal allergy.

The longer the tick feeds, the more alpha-gal they transmit into the host, increasing the likelihood that the host will develop an allergic reaction. Only after eating red meat—and sometimes mammal by-products like dairy—does a person with alpha-gal syndrome present symptoms. Usually several hours after eating red meat or dairy products, a person with alpha-gal syndrome may break out in hives, vomit, or experience anaphylaxis.

In the early stages of her illness, Velier couldn’t even cook mammal meat because the fumes would prompt an allergic reaction. “Food is the center of so much, socially,” Velier said. “Suddenly being told that your diet is just confined to poultry or fish was really alarming.”

Lone star ticks get their name from white patches on the backs of females. Some say the blotch vaguely resembles the shape of Texas. First identified in the mid-1700s in New York, lone star ticks later retreated almost entirely to southern states, likely due to widespread deforestation, says Dina Fonseca, chair of the Department of Entomology at Rutgers University. Increased deer hunting also drove down the population of the lone star tick’s preferred victim and reproductive host. “If you remove the habitat and you remove the host, you get no ticks,” Fonseca said.

Now that the population of white-tailed deer has rebounded from roughly 300,000 in 1900 to 30 million in 2026, lone star ticks have gradually been able to travel farther.

Thomas Mather is the director of the TickEncounter Resource Center at the University of Rhode Island, which facilitates a crowdsourced tick identification program. According to Mather, Rhode Island has seen a 1,200% increase in submissions of lone star tick photos since 2015. That’s partly because the ticks are almost entirely new to the Ocean State. But states that have long been home to the tick species have also seen “far above average” numbers this year, Mather said.

Lone stars feed three to four times during their roughly two-year lifespan. When searching for a host, many tick species perch on vegetation and wait for a host to brush past them. But lone star ticks, like mosquitoes, also have the ability to hunt their hosts by following carbon dioxide trails. While many ticks don’t feed on humans, Fonseca said lone star ticks are “quite aggressive biters of people.”

Since being diagnosed with alpha-gal syndrome about five years ago, Doug Regester has noticed that awareness of the illness has spread. “We went to a wedding reception last week and they had a note on the bottom of the menu that said all the food is alpha-gal safe,” Regester said.

Not all lone star tick bites lead to alpha-gal syndrome. “I don’t know that anyone knows yet what the relationship is between people that test positive for alpha-gal antibodies and what proportion of those people exhibit some level of symptoms,” Mather said. A lone star tick bit Dina Fonseca on the wrist, but she never developed an alpha-gal related allergy.

According to Fonseca, lone star ticks might not be the only ticks that cause the syndrome. They may simply prompt the allergic reaction more often because they hunt humans more aggressively than most other ticks. Fonseca said she knew of at least one example of someone developing a red meat allergy after being bitten by a different species of tick. “People have also talked about finding [alpha-gal syndrome] in other parts of the world where lone stars are not present,” she said. “So it’s not like it’s a one-to-one.”

Some people who get bitten by lone stars develop a condition known as ehrlichiosis, a bacterial illness that can include symptoms like headaches, fever, and muscle pains. Unless treated with antibiotics, ehrlichiosis can be fatal, especially for those with weakened immune systems. But Fonseca said that in her research, only about 2% of lone star ticks carry this bacteria.

Still, it’s important to take proper precautions. “You got bit by a tick. … Just take it out as soon as you can,” Fonseca said. “That’s the first thing, the best thing.”

Thomas Mather says the best way to stop the advance of lone star ticks is to inoculate white-tailed deer, similar to giving tick medicine to dogs. Most importantly, the medicine “has to be safe for people because people do eat deer,” he said.

After trying a holistic therapy that combines acupuncture and chiropractic care, Hannah Velier has noticed that the severity of her reaction to fumes from cooked meat has lessened. Her recent bloodwork also shows a reduced presence of alpha-gal antibodies, but she hasn’t wanted to run the risk of consuming mammal meat, just in case.

“I’ve been bitten by a bazillion ticks this season, so I very well may be a ticking time bomb as far as whether or not reactions will continue again,” she said.