Ticks That Spread a Red-Meat Allergy

If Lyme disease isn’t reason enough to avoid ticks, here’s another: the inability to enjoy a burger.
Odd as it seems, researchers say that bites from the voracious lone star tick are making some people allergic to red meat—even if they’ve never had a problem eating it before. The allergic reactions range from vomiting and abdominal cramps to hives to anaphylaxis, which can lead to breathing difficulties and sometimes even death. Unlike most food allergies, the symptoms typically set in three to six hours after an affected person eats beef, pork or lamb—often in the middle of the night.

The bite that seems to precipitate it may occur weeks or months before, often making it difficult for people to make the link. U.S. cases of the unusual allergy were first identified at the University of Virginia at Charlottesville in 2007, and are now being reported as far north as Nantucket, Mass., and on the east end of New York’s Long Island.
“It’s a huge problem out here,” says Erin McGintee, a pediatric and adult allergists in East Hampton, N.Y., who says she knows of more than 70 cases and sees several more each week. “I’ve tried to get the word out—but there are still a lot of people who don’t believe it,” she adds.
Tony Piazza, a landscape designer in Southampton, N.Y., first woke up in the middle of the night gasping for breath and covered in hives six years ago. Emergency-room doctors at Southampton Hospital gave him intravenous antihistamines and said it was probably an allergy, but they couldn’t determine the source. The same scene played out two or three times a year for the next few years, Mr. Piazza, 49, says.  “I was afraid that the next time, I wouldn’t wake up,” he says.  He noticed that the reaction occurred every time he ate lamb for dinner, even though he had never had food allergies before. Then it happened with steak and then hamburger. “I swore off red meat completely and the reactions stopped,” says Mr. Piazza. When he heard about the tick connection, it made sense, given his work. “I get ticks all the time,” he says.
Six hours after eating a burger, Robert Herrmann of Southampton, N.Y., began itching all over. ‘My whole body just felt wrong.’
Curiously, only the cancer patients from the southeastern “tick-belt” states had the allergic reaction. And as U. Va. researchers checked for the antibodies to alpha-gal in their (non-cancer-stricken) allergy patients, the same geographic pattern held true. What’s more, some had reported having allergic reactions hours after eating beef, lamb or pork.
The researchers began routinely asking all their allergy patients about tick exposure. “We would have people routinely pull down their socks and show us these massive tick bites on their ankles,” says Scott Commins, another U. Va. allergy specialist.
Dr. Platts-Mills himself returned from hiking in the Blue Ridge mountains in 2007 with his ankles covered in tiny lone star larvae. His blood soon tested positive for the telltale antibodies to alpha-gal. A few months later, he ate lamb for dinner at a meeting in London and awoke at 2 a.m. covered in hives. “I went back to sleep, pleased that I had another case to report on,” he says.
The researchers surmise that the delayed allergic reaction occurs because alpha-gal is most concentrated in animal fat, which takes several hours to digest.
That seems to be how the timing worked for Robert Herrmann, an environmental consultant in Southampton, who remembers a fall day in 2011 when he had eaten at McDonald’s for breakfast and Burger King for dinner. “Six hours later, to the minute, I was lying in bed and suddenly had a really bad itch on my head, then my armpit, then my side,” he says. “I told my wife, I know this is crazy, but you have to call an ambulance. My whole body just felt wrong.”
Like other sufferers, Mr. Herrmann had trouble getting doctors to believe him. “They said, ‘There’s no such thing as delayed anaphylaxis. Nobody had ever heard of it.”
Drs. Platts-Mills and Commins still haven’t conclusively proven that tick bites trigger the creation of the antibodies. Nor do they know whether something in the natural saliva of all lone star ticks causes the reaction or whether the ticks are picking up a pathogen from other hosts and transferring it to humans.
But evidence of the connection is mounting. To date, researchers have collected blood samples of more than 1,000 people with antibodies to alpha-gal, from Texas to Massachusetts, who report the delayed allergic reaction to red meat. The doctors have presented their research, funded by the National Institutes of Health, at allergy conferences and in a half-dozen medical-journal articles. In a study in the journal Pediatrics last month, they describe 45 children with similar symptoms in allergy clinics in nearby Lynchburg, Va.
No fatalities have been reported to date. But Joe Shields came close. Last September, the 40-year-old Keswick, Va., resident starting breaking out in hives many days around 5 p.m. At a conference in Atlanta, he passed out. “I felt like I was having a heart attack,” he says.
It took two more trips to emergency rooms before Mr. Shields learned about the red meat-tick bite connection. He’d gotten hundreds of tick bites while clearing trees around his home in August. He regularly ate cheeseburgers for lunch—and had had bacon, sausage and creamed chipped beef, “a mammalian-meat overload,” for breakfast in Atlanta.
“I’m sure other people are experiencing this and they don’t understand what’s going on,” he says.
Experts say such tick-triggered red-meat allergies may well have occurred, unnoticed, for decades. But they also think such cases are increasing as the population of lone star ticks grows and expands, along with its natural hosts, white-tailed deer and wild turkey.
“It’s very early days in this research—the tick connection was completely unexpected,” says Susan Little, a parasitologist at Oklahoma State University who is supplying the U.Va. researchers with lone star ticks, as well as blood samples from dogs with and without tick exposure, for further study. Dogs sometimes develop meat allergy too, and typically react with itching, skin lesions and hair loss, Dr. Little says.
And lone stars may not be the only tick carrier. Several years before researchers made the connection, Sheryl van Nunen, an expert in anaphylaxis at Royal North Shore Hospital in Sydney, Australia, linked red-meat allergies she was seeing in patients to bites from another type of tick, Ixodes holocyclus, which feed on bandicoots, a type of Australian marsupial. She says she has since identified more than 400 such cases. Other meat-allergy cases, linked to other ticks, have been reported in Spain, France and Sweden.
Experts don’t know why some people who are bitten by lone star ticks develop the antibodies to alpha-gal and others don’t. But cases do seem to run in families. “I have a father-daughter pair, and a mother-son and a couple of sets of cousins, so there is probably some kind of genetic component,” says Dr. McGintee.
How much red meat is needed to cause a reaction also varies widely. Some patients react strongly to pork sausage or lamb, but can eat lean roast beef without having symptoms. Others react even to chicken sausage in pork casing or to marshmallows and gel-cap vitamins, since gelatin is made from animal byproducts.
The good news is that the allergic reaction seems to fade after a few years in some sufferers if they avoid additional tick bites.  Others keep getting bitten and have sworn off meat for good. “I dream about eating steak,” Mr. Piazza says. “But I wouldn’t take the risk.”
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