For many people, a tick bite raises immediate concerns about Lyme disease. But ticks can create another serious and potentially life-changing health risk: alpha-gal syndrome, an allergy that can make someone react to beef, pork, dairy, gelatin and other products derived from mammals.
Unlike Lyme disease, alpha-gal syndrome is not an infection. It is an allergic condition that can develop after a tick bite. Unlike most food allergies, AGS symptoms may not appear until hours after a meal. That delay can make the connection between a hamburger at dinner and hives, stomach pain or difficulty breathing in the middle of the night difficult to recognize.
The issue has become especially urgent on Martha’s Vineyard, where lone star tick populations and positive alpha-gal tests have risen dramatically. The Island is now responding on multiple fronts through public-health surveillance, clinical care, education, research, deer-management discussions and local tick-reduction efforts. As part of that response, ohDEER Martha’s Vineyard is helping residents reduce tick pressure around the homes, schools, daycares and businesses where they spend time outdoors.
Alpha-gal syndrome is an IgE-mediated allergy to galactose-alpha-1,3-galactose, a sugar commonly called alpha-gal. The molecule is found in most non-primate mammals and products made from them. Humans and other primates do not naturally produce it. Current evidence indicates that substances introduced through a tick’s saliva can prompt the immune system to produce IgE antibodies to alpha-gal. Once sensitized, a person may have an allergic reaction after eating or being exposed to a product containing the same sugar.
In the United States, the condition is primarily associated with the bite of the lone star tick. The Centers for Disease Control and Prevention also reports less common associations with blacklegged and western blacklegged ticks. Not everyone bitten by one of these ticks develops AGS, and researchers are still studying why some people become sensitized while others do not.
AGS is not passed from person to person, and it is not caused by bacteria or a virus. It is a noninfectious, tick bite-associated allergy. Symptoms may not begin until weeks or months after the bite, and some people do not remember being bitten at all.
Most familiar food allergies cause symptoms within minutes. According to the CDC’s symptom guidance, AGS symptoms usually begin two to six hours after exposure to red meat, dairy or another product containing alpha-gal.
That delay can obscure the trigger. Someone may eat beef at 7 p.m., go to bed feeling normal and wake several hours later with hives or severe gastrointestinal symptoms. The timing can lead patients and healthcare providers to consider many other explanations before connecting the reaction to a meal.
Alpha-gal syndrome symptoms can include:
Reactions are not always predictable. One person may have gastrointestinal symptoms without hives, while another may experience swelling or anaphylaxis. The same person can also react differently on separate occasions, even after exposure to the same food or product.
A positive blood test alone does not prove that someone has clinical AGS. People can carry alpha-gal-specific antibodies without developing symptoms. Diagnosis typically combines a detailed medical history, compatible symptoms and an alpha-gal-specific IgE blood test. A healthcare provider may also recommend allergy skin testing.
Anyone experiencing trouble breathing, throat or tongue swelling, fainting or other signs of anaphylaxis should seek emergency care immediately. People who have been prescribed epinephrine should follow their emergency plan and still obtain urgent medical care after using it.
The greatest concentration of suspected U.S. alpha-gal syndrome cases has historically been in the South, Midwest and mid-Atlantic, where lone star ticks are common. A CDC analysis of testing from 2017 through 2022 found a nearly continuous region of higher suspected-case rates across parts of Oklahoma, Kansas, Arkansas, Missouri, Mississippi, Tennessee, Kentucky, Illinois, Indiana, North Carolina, Virginia, Maryland and Delaware. Suffolk County, New York, had the highest total among U.S. counties in that analysis.
The map is not static. Current CDC lone star tick surveillance describes the species as widely distributed across the Northeast, South and Midwest. Ticks may also be present in counties that have not yet documented an established population, and people can acquire bites while traveling.
By 2022, the CDC estimated that as many as 450,000 people in the United States might be affected. A newer 2026 CDC study found the highest alpha-gal antibody prevalence among sampled blood donors in Arkansas, Kentucky, Missouri, Tennessee and Virginia. However, antibodies are not the same as symptomatic AGS, so the results should not be interpreted as the percentage of residents with the allergy.
Martha’s Vineyard shows why northern communities also need to pay attention. Lone star ticks are now well established on the Island, and local testing has increased at an extraordinary rate.
The basic strategy for managing AGS is to avoid the foods and products that trigger reactions while preventing additional tick bites. There is no universal alpha-gal diet because sensitivity varies significantly. An allergist or another knowledgeable healthcare provider can help determine an individualized plan.
The CDC’s list of products that may contain alpha-gal includes mammalian meats such as:
Some patients must also avoid mammal-derived gelatin; foods cooked with lard, tallow or suet; and meat broths, stocks, bouillon or gravies. Dairy contains alpha-gal, but many people with AGS tolerate some milk products. The decision to eliminate dairy should be based on a patient’s reactions and medical guidance, not assumed from a positive test alone.
Chicken, turkey, duck, fish, seafood, eggs, fruits and vegetables do not contain alpha-gal. These foods can become the foundation of a revised diet, although every person’s other allergies and nutritional needs still matter.
Living with the condition involves much more than replacing steak with chicken. Patients may need to read labels closely, ask restaurants about broths and cooking fats, watch for gelatin in candy or desserts and communicate about cross-contact. Dining out, traveling and social events can require more planning. Some people carry a chef card so restaurant staff can check ingredients more accurately.
The condition can also affect healthcare decisions. Gelatin, glycerin, magnesium stearate, bovine extract and other mammal-derived ingredients may appear in certain medications or vaccines. Animal-derived products can include some heart valves, monoclonal antibodies, heparin and certain antivenoms. Not every patient reacts to them, and people should never stop a medication or decline needed care without medical guidance. Patients should tell their physicians, dentists and pharmacists about AGS and review new products with them.
Outdoor habits may change, too. The CDC recommends preventing additional tick bites because new bites may reactivate allergic reactions.
Statistics cannot fully show how the condition reshapes everyday life. The experiences of Martha’s Vineyard residents reveal the practical, emotional and social burden behind the numbers.
In a Martha’s Vineyard Times story about three Islanders living with AGS, writer Nancy Aronie described spending about a year trying to identify the source of itching, hives and welts. Dinner guests with alpha-gal restrictions finally helped her connect her own symptoms. She removed red meat from her diet and reported feeling better, although cheese was the food she missed most.
Chef Jean-Marc Dupon’s experience demonstrates the stakes of accidental exposure. After a known lone star tick bite and anaphylaxis, testing confirmed AGS. He now carries epinephrine and brings cards listing prohibited foods to restaurants for the kitchen. For someone whose life and family history are closely connected to food and fine dining, the diagnosis changed what he eats and how he navigates meals away from home.
Hunter, farmer and businessman Brian Athearn responded to his diagnosis by changing his diet and exercising more, losing more than 40 pounds. He continues to hunt even though he cannot eat the venison, donating meat to the food pantry or trading it for fish and scallops. His story reflects a painful irony: hunters can help reduce an overabundant deer population that supports lone star ticks even when their families are already living with AGS.
The risks are not limited to obvious foods. At a 2025 Island tick summit, Athearn described his son experiencing a severe reaction after taking gel-cap pain relievers and emphasized access to epinephrine. People with AGS may need to review medication ingredients with a clinician or pharmacist rather than assume a familiar product is safe.
Martha’s Vineyard has experienced a sharp rise in alpha-gal testing and positive results. The Martha’s Vineyard Hospital recorded only two positive results out of nine tests in 2020. By the end of 2025, the hospital had recorded 742 positive results among 1,689 tests, according to the Vineyard Gazette. The hospital had recorded another 572 positive results in 2026 as of late August, the Gazette later reported.
These are positive test results, not necessarily unique clinical cases. Some people may be tested more than once, and diagnosis requires compatible symptoms as well as testing. Even so, the increase demonstrates the scale of concern and demand for care.
The broader tick burden is also severe. Island public-health data presented in 2025 showed Lyme disease and babesiosis rates about 11 times the Massachusetts average. Local experts estimate the Vineyard’s deer density at roughly 53 to 55 deer per square mile, compared with the state’s target of 12 to 18. White-tailed deer are important hosts for adult lone star ticks, helping large tick populations persist.
Massachusetts began requiring AGS reporting to the Department of Public Health on April 1, 2026, initially for one year with the possibility of an extension. The goal is to move beyond laboratory totals and better understand where cases occur, common symptoms and triggers, and the effects on year-round residents.
The Island’s response also includes Tick Free MV, expanded clinical and research resources, public education, support groups, deer surveys and discussions about hunting access and wildlife management. Martha’s Vineyard Hospital has also launched research focused on how patients’ antibody levels change over time and whether additional tick bites affect their sensitivity.
No single intervention will solve this crisis. Progress will require coordinated action that reduces tick encounters while protecting the Island’s residents, visitors and ecosystems.
ohDEER Martha’s Vineyard has worked on the Island since 2014, making it one of the area’s longest-running providers of All-Natural Deer and Tick repellent services on the island. In an August 2026 Martha’s Vineyard Times report, owner Mario “Eddie” Spindola explained that the business was created to give families and property professionals a more environmentally conscious alternative to conventional chemical applications.
The local team now treats around 100 properties each week, approximately twice as many as it did the previous year, and also serves schools, daycares and businesses. Five trucks operate as many as six or seven days a week during busy periods. Technicians focus applications around lawns, landscaping and property edges where people, pets, deer and ticks may come into contact.
The team’s liquid tick deterrent includes castor oil, lemongrass, geraniol, sodium lauryl sulfate and corn oil. It also applies a powder deer deterrent around yard perimeters. By making treated spaces less appealing to ticks and deer, these services can be one layer in a broader plan to reduce bites associated with AGS and other tick-related health concerns.
The local work is responding to a clear need. Oak Bluffs homeowners Bill and Robin Davies told the Times that they had previously found many ticks on their dog and had seen increasing deer activity around their property. After beginning service with ohDEER, they observed a noticeable difference in tick and deer activity while continuing to see bees, butterflies and dragonflies in their yard.
At the same time, responsible tick management requires transparency. The long-term effects of widespread natural and synthetic spray use on the Vineyard’s ecology and water quality need additional study. The Times reported that Spindola supports more research, and technicians described avoiding direct applications to bees, butterflies, dragonflies and other visible beneficial insects. Property treatments should be carefully planned and used alongside personal prevention, not treated as a guarantee that a yard is tick-free.
That layered approach matters. Reducing tick habitat and activity around a property can complement repellents, protective clothing, tick checks, landscape maintenance, community surveillance and Island-wide deer-management strategies. For ohDEER Martha’s Vineyard, helping families enjoy more time outside also means participating honestly in a larger public-health conversation and continuing to adapt as research develops.
No. Alpha-gal syndrome is an allergic condition associated with tick bites. It cannot be spread through casual contact, food sharing, coughing or person-to-person transmission.
No. In the United States, the allergy is most often associated with a lone star tick bite, with fewer cases linked to blacklegged and western blacklegged ticks. Not everyone bitten develops the condition, and researchers are still studying why some people become sensitized.
Symptoms usually appear two to six hours after exposure, although timing and severity can vary. This delay is one reason alpha-gal syndrome can be difficult to recognize.
Chicken, turkey, fish, seafood and eggs do not contain alpha-gal. Individual dietary needs and other allergies may still apply.
No. Dairy contains alpha-gal, but many people with the condition tolerate some dairy products. Patients should work with an allergist or another knowledgeable healthcare provider to identify their personal triggers.
Diagnosis generally combines symptoms and exposure history with a blood test for alpha-gal-specific IgE antibodies. A positive blood test without compatible symptoms does not necessarily mean a person has clinical alpha-gal syndrome.
Some people’s sensitivity decreases over time, especially when they avoid additional tick bites. Others continue to react for years. A patient should not reintroduce a known trigger without medical guidance.
Use prescribed epinephrine according to your emergency plan and seek immediate emergency care. Trouble breathing, throat or tongue swelling, fainting and rapidly worsening symptoms require urgent attention.
No method can eliminate all tick-bite risk. Property treatments can be one part of a layered prevention plan that also includes repellents, protective clothing, tick checks, habitat management and community-level action.
No. The highest numbers of suspected cases have historically occurred in Southern, central and eastern states, but lone star ticks are widely distributed in the Northeast, South and Midwest. Martha’s Vineyard is now a significant northern hotspot.
This article is for educational purposes and is not a substitute for diagnosis or treatment from a qualified healthcare professional. Anyone with possible alpha-gal syndrome symptoms should consult a clinician, and anyone experiencing a severe allergic reaction should seek emergency care immediately.
