The year 2026 has been great for ticks. The number of emergency department visits for tick bites have reached near-record highs across the United States, with the Midwest and Northeast experiencing the highest rates of activity, according to the federal government’s tick bite data tracker.
Maya Jerath, MD, PhD, a WashU Medicine allergist and immunologist, runs one of the largest clinical practices in Missouri treating patients with alpha-gal syndrome, a potentially life-threatening allergic reaction that can be triggered by bites from the lone star tick and other species. Jerath has researched the tick-borne illness for more than two decades while also treating over 650 patients diagnosed with alpha-gal syndrome — a number she said is increasing rapidly. We asked Jerath to share her expertise on alpha-gal syndrome.
What is alpha-gal syndrome, and how do tick bites cause it?
Alpha-gal syndrome is a distinct allergic reaction triggered by an immune response to a sugar molecule known as alpha-gal found in beef, pork, lamb and sources such as wild mammalian game and organ meats. When certain ticks bite a human, it is believed they induce sensitization to this molecule, which predisposes the human immune system to recognize it as an allergic threat.
Within four to eight hours after consumption, an allergic person can develop physical reactions such as hives, vomiting, diarrhea and life-threatening breathing problems or cardiovascular collapse. The exact reason ticks trigger the allergy is still not fully understood, and it’s important to note that not everyone bitten by the lone star tick will develop the allergy.
Why is alpha-gal syndrome attracting more attention?
Alpha-gal syndrome is being diagnosed more often, causing greater awareness. The allergy was thought to be confined mainly to southeastern and mid-Atlantic states, however, it is increasingly recognized in the Midwest and along the Atlantic coast. Milder winters coupled with increased deer populations, especially in suburbs, have increased tick populations in our region, making Missouri a hotspot for alpha-gal syndrome and WashU Medicine — with expertise in allergies and infectious diseases — an ideal place for alpha-gal research.
What do you study about alpha-gal?
I’m involved in clinical and basic research studies. Clinically, I collect detailed patient histories, blood tests and reaction patterns that I compare with symptoms. This helps to distinguish true allergy from a positive test alone and guides more accurate diagnosis and treatment. I treat many patients who have had symptoms for 20 or 30 years before coming to WashU Medicine and getting the right diagnosis, while others test positive but never develop symptoms.
For those with a true allergy, most improve by avoiding red meats, though a subset also reacts to dairy or gelatin. Some eventually improve enough to reintroduce meat.
I also work with collaborators at WashU Medicine who conduct basic science studies examining how tick exposure can change the immune system at the cellular level and cause people to develop alpha-gal sensitization. This is important because it could lead to much needed and improved diagnosis, prevention and treatment.
Has your research led to clinical developments?
My research has helped identify factors that lower the threshold for a patient to react. This information feeds into the counseling we provide patients to manage their condition. In addition, we have developed at-home protocols that can help to safely reintroduce meat to patients whose alpha-gal antibody levels have cleared or nearly cleared. This is significant for patients because they can expand their diet and release anxiety that surrounds living with a food allergy.
Alpha-gal is trickier than other food allergens because the reaction is not immediate. My approach starts with introducing very small amounts of lean meat. We gradually increase portion sizes and offer fattier cuts. I tell the patients exactly what to buy and how to advance each day. About 10% of my patients have successfully returned to eating meat, with only a small number needing to stop because of symptoms.
What unanswered questions remain about alpha-gal?
Researchers are still trying to determine whether asymptomatic antibodies against alpha-gal cause long-term internal inflammation and exactly which environmental cofactors, in addition to tick bites, cause the allergy to develop. More data is also needed to determine whether mammalian-derived medical products — such as some prescription medications or cow or pig heart valves, which are implanted when patients’ own valves are faulty — are entirely safe for patients with alpha-gal syndrome. In addition, questions remain about why some people develop symptoms while others with a positive test do not. We’re also trying to understand what in the blood or immune system predisposes someone to alpha-gal syndrome, and whether treatments could reduce reactions or improve tolerance.
Jerath is a professor and associate clinical chief in the John T. Milliken Department of Medicine’s Division of Allergy and Immunology.