A bizarre condition caused by tick bites appears to have claimed its first known human. Scientists have just linked a 47-year-old New Jersey man’s death last year to alpha-gal syndrome, commonly known as the red meat allergy.
Researchers at the University of Virginia School of Medicine detailed the tragic incident in a case report released this week. The man seemed to have experienced a severe allergic reaction to the burger he had eaten four hours earlier, with experts later finding evidence of alpha-gal sensitivity in his blood. Though this might be the first death tied to red meat allergy, it may not be the last, since cases in general are rising in the U.S.
“We report here the first documented fatal case of [alpha-gal syndrome] occurring after consuming mammalian meat,” the researchers wrote in their paper, published Wednesday in the Journal of Allergy and Clinical Immunology: In Practice.
A deadly red meat reaction
According to the case report, the man, an airline pilot, died in the summer of 2024.
Two weeks before his death, during a camping trip with his family, they had eaten a late dinner of beef steak. Several hours later, the man awoke with severe abdominal pain, diarrhea, and vomiting. But his condition eventually improved, and he went back to sleep, recovering quickly enough to go on a 5-mile walk the next day. He and his wife considered seeing a doctor, but they weren’t sure how to explain what had happened.
On the fateful day, the man and his wife went to a barbecue where he ate a hamburger at around 3:00 p.m. All seemed fine until around 7:20 p.m., when he went to the bathroom. His son discovered that he was sick again by 7:30 p.m. and soon found his father unconscious on the bathroom floor with vomit around his mouth. He called 911 and attempted resuscitation, as did the paramedics that arrived and took him to the hospital. But by 10:22 p.m., the man was officially declared dead.
An initial autopsy found nothing unusual in his major organs nor any other clear culprit for his passing, and the coroner ruled it a “sudden unexplained death.” But his wife consulted with her friend, a doctor, and they eventually reached out to the researchers to see whether alpha-gal syndrome could have played a role. With her permission, the researchers were given access to test the man’s postmortem blood for themselves.
The man’s blood showed relatively high levels of IgE antibodies to alpha-gal, the researchers found, which is important because IgE is the type of antibody that helps cause a food allergy. He also had high levels of the allergy-related enzyme tryptase—levels high enough to be consistent with a severe allergic reaction, or anaphylaxis.
Given the man’s otherwise good health, the blood test results, his earlier symptoms, and the recent exposure to beef, it’s almost certain that red meat allergy was to blame for his death, the researchers concluded.
A rising threat
Most mammals carry the sugar alpha-gal in their muscles, with the notable exception of humans and other primates. Ordinarily, eating the meat of other mammals isn’t a problem for us, even if it contains the sugar. But for reasons scientists are still trying to understand, the bite of a lone star tick (and possibly other species) can sometimes trigger a new sensitivity to alpha-gal in people.
It isn’t just the source of illness that makes red meat allergy weird. For starters, it’s the only IgE-related food allergy to a carbohydrate rather than a protein. Secondly, as in this case, it often takes hours after exposure to red meat for symptoms to appear, whereas it will usually take minutes for other foods. Though alpha-gal syndrome can sometimes fade away over time, many who have it will never be able to safely eat red meat again.
It’s estimated that as many as 450,000 Americans have developed alpha-gal syndrome since 2010. But both the public and doctors in general are still unaware of its existence, the researchers note. That’s especially worrying since more and more Americans are becoming exposed to the ticks that cause it. So if nothing else, they hope this case can promote awareness of a real and growing public health concern.
“The significance of this case is that a large and increasing population of the United States is being exposed to the lone star tick, both because the tick is moving north and because there are now large populations of deer in many states,” they wrote. “[I]t is clear that there is a need for better education of both the professionals and the public.”
