Bad bite: A tick can make you allergic to red meat

New York - A bug can turn you into a vegetarian, or at least make you swear off red meat. Doctors across the US are seeing a surge of sudden meat allergies in people bitten by a certain kind of tick.

This bizarre problem was only discovered a few years ago, but is growing as the ticks spread to more parts of the United States. In some cases, eating a burger or a steak has landed people in the hospital with severe allergic reactions.

Few patients seem aware of the risk, and even doctors are slow to recognise it. As one allergist who has seen 200 cases on New York's Long Island said, "Why would someone think they're allergic to meat when they've been eating it their whole life?"

The culprit is the Lone Star tick, named for Texas, a state famous for meaty barbecues. 

Researchers think some other types of ticks also might cause meat allergies; cases have been reported in Australia, France, Germany, Sweden, Spain, Japan and Korea.

Here's how it happens: The bugs harbour a sugar that humans don't have, called alpha-gal. The sugar is also is found in red meat - beef, pork, venison, rabbit - and even some dairy products. It's usually fine when people encounter it through food that gets digested.

But a tick bite triggers an immune system response, and in that high-alert state, the body perceives the sugar the tick transmitted to the victim's bloodstream and skin as a foreign substance, and makes antibodies to it. That sets the stage for an allergic reaction the next time the person eats red meat and encounters the sugar.

It happened last summer to Louise Danzig, a 63-year-old retired nurse.

Hours after eating a burger, "I woke up with very swollen hands that were on fire with itching," she said. As she headed downstairs, "I could feel my lips and tongue were getting swollen," and by the time she made a phone call for help, "I was losing my ability to speak and my airway was closing."

She had had recent tick bites, and a blood test confirmed the meat allergy.

"I'll never have another hamburger, I'm sure," Danzig said. "I definitely do not want to have that happen to me again."

In Mount Juliet, 71-year-old Georgette Simmons went to a steakhouse on 1 June for a friend's birthday and had a steak.

"About 04:30 in the morning I woke up and my body was on fire. I was itching all over and I broke out in hives. Nothing like that had ever happened to me before," she said.

A few weeks later, for a brother's birthday, she ordered another steak. Hours later she woke "almost hysterical" with a constricted throat in addition to hives and a burning sensation. She, too, recalled tick bites.

Dr Robert Valet at Vanderbilt University said Simmons was one of two patients he diagnosed with the meat allergy that day. He warned her it could be worse next time.

"I never did eat a lot of red meat anyway, but when I go out I like a nice fillet. Right now I wouldn't even eat hamburger meat," Simmons said.

At the University of Virginia in Charlottesville, "I see two to three new cases every week," said Dr Scott Commins, who with a colleague, Dr Thomas Platts-Mills, published the first paper tying the tick to the illness in 2011.

One of the first cases they saw was a bow hunter who had eaten meat all his life, but landed in the emergency department several times with allergic reactions after eating meat. More cases kept turning up in people who were outdoors a lot.

"It seemed something geographical. We thought at first it might be a squirrel parasite," Commins said. "It took us a while to sort of put everything together" and finger the tick, he said.

Dr Erin McGintee, an allergy specialist on eastern Long Island, an area with many ticks, has seen nearly 200 cases over the last three years. At least 30 involved children, and the youngest was 4 or 5. She is keeping a database to study the illness with other researchers.

"It is bizarre," she said. "It goes against almost anything I've ever learned as an allergist," because the symptoms can occur as long as eight hours after eating meat, rather than immediately, and the culprit is a sugar - a type of carbohydrate - whereas most food allergies are caused by proteins, she said.

Allergic reactions can be treated with antihistamines to ease itching, and more severe ones with epinephrine. Some people with the allergy now carry epinephrine shots in case they are stricken again. 

Doctors don't know if the allergy is permanent. Some patients show signs of declining antibodies over time, although those with severe reactions are understandably reluctant to risk eating meat again.

Even poultry products such as turkey sausage sometimes contain meat by-products and can trigger the allergy.

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Sudika Harkhu 2014/08/08 06:11:56 AM
karma perhaps?
Bradly Minnaar 2014/08/08 06:13:46 AM
Evil little thing musnt come near me.
Vanetia Mentor 2014/08/08 06:18:58 AM
That might not be a bad thing. .... people eat way too much red meat. I wish there were a tick who's bite made you alergic to sugar. ...I eal way too much sugar . :(
Spijo Skhokho 2014/08/08 06:26:49 AM
extinct the damn tick
Mandilakhe Madi 2014/08/08 06:29:26 AM
I think we should genetically alter its DNA for S.A to fight our biggest's obviously gonna help wif the USA's burgers obsession lol
Anthoula Joshua 2014/08/08 06:39:55 AM
That would cause an economic melt down in SA. What would people do on a weekend? Braai veggie boerewors? What would we do with our braai grids? We would die without meat. Kill that tick now.
Anthoula Joshua 2014/08/08 06:43:41 AM
Can they find one for bad carbohydrates rather? We will all be lean and healthy. Just please, not red meat. I will die for the lack of steak or biltong. LOL!!!
Yvette Selina Clark 2014/08/08 07:09:46 AM
Finally a cause established. My allergic reactions especially to raw beef and pork are getting worse as I get older. I don't eat meat at all, only fish; but have to book for a large nest eating family. I shower from head to toe after cooking and have to take antihistamines and nausea tablets while cooking. I feel normal after reading this...
CJS 2014/08/08 07:17:48 AM
Ye ye what ever good come back for all the bad stuff the give to animals
James Schutz 2014/08/08 07:25:55 AM
This spells trouble for a parent or spouse who is a vegetarian and is looking for a simple way to take red meat off the menu for the rest of the family!!!Funny thing is a hamburger and chips is the USAs staple meal,like our pap gravy and boerewors.As this spreads in the USA and other places the price of red meat will drop COOL!!!