New data from the Centers for Disease Control and Prevention (CDC) shows the rate of Americans developing a rare red meat allergy from tick bites is rising
Los Angeles, August 4, 2023 — The Centers for Disease Control and Prevention (CDC) has made public new data about the incidence of Alpha-gal syndrome (AGS), a potentially life-threatening allergy to mammals’ flesh that is linked to the saliva of the lone star tick. This potentially lethal red meat allergy may already have impacted as many as 450,000 U.S. citizens.
Made public on July 28, 2023, the data issued by the CDC in two papers in the Morbidity and Mortality Weekly Report number 30 shows that, between 2010 and 2022, there were more than 110,000 suspected cases of alpha-gal syndrome identified. But, because its diagnosis requires a positive diagnostic test and a clinical exam, it is estimated that between 96,000 and 450,000 Americans may have been affected since 2010.
One of the papers is titled “Geographic Distribution of Suspected Alpha-gal Syndrome Cases — United States, January 2017–December 2022.” It concludes that the number of suspected AGS cases in the United States has increased substantially since 2010. The states with established populations of lone star ticks have been impacted the most, although suspected AGS cases were also identified in areas outside of this tick’s range. From 2017 to 2021, the number of cases increased by about 15,000 per year.
What Causes this Red Meat Allergy?
AGS (also called alpha-gal allergy, red meat allergy, or tick bite meat allergy) is a serious allergic condition some people experience after they consume food or products containing alpha-gal (galactose-α-1,3-galactose), a sugar molecule found in most mammals but not naturally found in humans. After having been bitten by these ticks, some people may become ill after consuming red meat, namely flesh from cows, rabbits, deer, sheep, etc. But, it could also sicken those tick bite victims who consume animal products like gelatin and dairy and certain pharmaceuticals.
The evidence suggests that AGS is primarily associated with the bite of a lone star tick (Amblyomma americanum), mostly found in southern and eastern parts of the USA, but other kinds of ticks have not been ruled out. This tick is identifiable by a white spot on the back. The heating of the climate is likely to increase the range of the ticks that trigger this disease, placing more northern populations at risk.
Dr. Ann Carpenter, epidemiologist and lead author of one of the papers released by the CDC, said in a press release, “It’s critical for clinicians to be aware of AGS so they can properly evaluate, diagnose, and manage their patients and also educate them on tick-bite prevention to protect patients from developing this allergic condition.”
Dr. Johanna Salzer, senior author on the two CDC papers on this issue, said, “The burden of alpha-gal syndrome in the United States could be substantial given the large percentage of cases suspected to be going undiagnosed due to non-specific and inconsistent symptoms, challenges seeking health care, and lack of clinician awareness.”
“Alpha-gal syndrome is an important emerging public health problem, with potentially severe health impacts that can last a lifetime for some patients.” — Dr. Ann Carpenter, epidemiologist and author of one of the study
Not Many Doctors Know about the Red Meat Allergy
One of the papers released by the CDC is titled “Health Care Provider Knowledge Regarding Alpha-gal Syndrome — United States, March–May 2022.” This one reports on a nationwide survey of health care providers (HCP) that showed that 42% of the 1,500 respondents were not aware of AGS, and another 35% were not confident in their ability to diagnose or manage AGS patients. Only 5% said they were “very confident” in their ability.
This result could be partly explained by the fact this syndrome was not discovered until 2008, after US researchers found unexpected results while testing a drug used to treat cancer. Also, because of how slowly the human body digests meat, it can be very difficult to link the symptoms to red meat consumption as they may not appear immediately after eating animal products.
The report states, “Limited HCP knowledge about AGS is concerning, especially because the number of suspected cases is increasing, and the range of the tick primarily associated with this condition is expected to expand. Improved HCP education might facilitate a rapid diagnosis of AGS, improve patient care, and support public health understanding of this emerging condition.”
Alpha-gel syndrome Symptoms can vary from person to person and include stomach cramps, diarrhea, hives and shortness of breath that could trigger fatal anaphylaxis.
This meat allergy is not the only one that has been detected. The paralysis tick (Ixodes holocyclus) has also caused similar meat allergies in Sydney, Australia. It does seem that the best way to reduce the risk of getting this disease is to become vegan, as vegans who are bitten by these dangerous ticks are less likely to show any allergic reaction as they do not consume any animal products containing alpha-gal (although they may still get it from medicines or highly processed food).
“It’s important that people who think they may suffer from AGS see their healthcare provider or an allergist, provide a detailed history of symptoms, get a physical examination, and a blood test that looks for specific antibodies to alpha-gal.” —Dr. Johanna Salzer, senior author on the two CDC papers
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Jordi Casmitjana is a vegan zoologist and author.