Feeling sick after eating that steak dinner? You could have a rare but potentially severe tick-borne allergy

Health professionals need to know more about alpha-gal syndrome – a rare tick-borne condition that can cause severe and even deadly allergic reactions to red meat and other food products derived from mammals, U. S. researchers warn. 

That warning about the syndrome – which is usually caused by a bite from the lone star tick – comes in an alarming case study about an otherwise healthy, middle-aged New Jersey man who died just hours after eating a hamburger at a barbecue party. The article is the work of a group of researchers from the University of Virginia School of Medicine. It was published in the Journal of Allergy and Clinical Immunology (JACI) in December of 2025.

“The syndrome is now well recognized in many areas of the south but not in the areas where the tick is spreading,” the authors write.

“We report here the first documented fatal case of (alpha-gal syndrome) occurring after consuming mammalian meat.”

The man’s death underscores a growing public health crisis as climate change fuels the northward spread of several species of disease-causing ticks. Lone star ticks have been identified in several regions in this country, but the Public Health Agency of Canada (PDF) says they are not yet “established” here and it’s “rare” that they cause alpha-gal syndrome. However, the blacklegged tick, which carries the pathogen that’s causing an explosion of Lyme disease cases, is already well established in much of southern Canada. In rare cases, it can also transmit alpha-gal syndrome, in addition to anaplasmosis, babesiosis, Rocky Mountain spotted fever and other serious infections. 

Even so, alpha-gal syndrome isn’t a reportable disease in Canada so there’s no official estimate of national case numbers, although CBC News reported on a case involving a woman in Nova Scotia in July of this year. In the United States, the Centers for Disease Control and Prevention (CDC) estimates that up to 450,000 people have the syndrome. One study suggests case numbers there are rising sharply. 

‘Sudden unexplained death’

The JACI article describes the case of a 47-year-old airline pilot who died in the summer of 2024. The first signs of trouble emerged when he woke up with severe stomach pain, diarrhea and vomiting after eating some beef while on a camping trip. He eventually felt better and went back to sleep.

“Two weeks later at home in New Jersey, he and his wife went to a barbecue where he ate a hamburger at approximately 3:00 PM,” the study reads.

“At 7:20 PM, he went to the bathroom, and by 7:30 PM, their son was on the phone with his mother saying, ‘dad is getting sick again.’ Shortly thereafter he found his father unconscious on the floor of the bathroom with vomit around him; the son called 911 at 7:37 PM and initiated resuscitation. The paramedics continued resuscitation efforts for two hours, which included transferring the patient to hospital, but at 10:22 PM, he was declared dead.”

Why the man died was a medical mystery at first. The post mortem examination showed no “significant abnormalities” and the autopsy report described the case as a “sudden unexplained death,” the researchers write.

The man’s wife wanted the mystery solved and asked a physician who is a personal friend to review the autopsy report.

“They then contacted our group in Virginia to address the possible role of (alpha-gal syndrome) and gave permission for the Medical Examiner’s Office to send the postmortem blood to Virginia,” the authors state. 

Tests determined the man died of anaphylactic shock. His wife told the University of Virginia researchers he had been bitten by ticks in the past, but not that year. She did report, however, that he’d suffered several “chigger bites.” What people in the northeastern U.S. often describe as chiggers are actually the larvae of lone star ticks, the article states. 

What to watch for

Female lone star ticks are light reddish brown to dark brown and have a distinctive white spot on their backs. The males are smaller and are dark brown. They lack the white spot but have white or tan markings. Both males and females can transmit a sugar molecule – galactose-alpha-1,3-galactose – which then can cause an allergic reaction when you eat or drink certain products, including:

• Red meats: Beef, pork, lamb, venison, goat, bison, and rabbit,
• Organ meats: Liver, kidneys, heart, and intestines from mammals,.
• Fats and broths: Lard, tallow, suet, and mammalian meat broths, stocks, or gravies
• Gelatin: Jell-O, marshmallows, gummy candies, and capsule coatings for pills.
• Dairy products: Cow’s milk, butter, cheese, and cream (tolerated by some people, but triggers reactions in others).
• Processing agents: Carrageenan (a seaweed additive that can cross-react for some sensitive individuals) and certain animal-derived stearates or glycerine.

There isn’t much your physician can do to treat alpha-gal syndrome except to tell you to avoid eating the foods that trigger it and carry an EpiPen. You should also become an avid reader of ingredients on food packages. 

Mild reactions will respond to the usual allergy medications but if you feel a severe allergic response coming on, you should get to an emergency ward immediately. 

Better education

The authors of the case study published in JACI say public health authorities need to raise awareness of alpha-gal syndrome. 

“It is clear that there is a need for better education of both the professionals and the public,” the authors warn. 

“The CDC has documented that a large number of physicians are not aware of (alpha-gal syndrome); however, we would argue that there is a major need for public education in areas where the tick is increasing.”