Martha's Vineyard Hospital recorded 572 positive tests for alpha-gal, the antibody linked to a tick-borne red meat allergy, in 2026 through August, the Vineyard Gazette reported. In 2020, the same hospital ran just nine alpha-gal tests, and two came back positive.

The numbers climbed sharply in between. The hospital logged 742 positive results out of 1,689 tests in 2025, according to a Dukes County announcement, and this year's count is on a similar pace.

The surge on one island reflects a much larger shift. The lone star tick, the species most often tied to alpha-gal syndrome, has been moving north into New England, and residents of the Northeast and Midwest who once had little reason to worry about it now do.

A Sugar in Meat That Can Turn Into an Allergy

Alpha-gal is a sugar molecule found in most mammals, but not in people, according to the Centers for Disease Control and Prevention. It is present in red meat such as beef, pork, lamb and venison, in many dairy products, and in some medications and other products made with mammal ingredients.

When certain ticks bite, they can introduce alpha-gal into the skin. In some people, the immune system responds by making antibodies against it. Later, eating red meat can trigger an allergic reaction, often hours after the meal, which makes the cause hard to recognize.

Reactions range from hives and stomach pain to severe, life-threatening anaphylaxis. Ellen McMahon, chief of medicine at Martha's Vineyard Hospital, said the delay is part of what makes the condition tricky. "Symptoms can be delayed and vary widely from person to person, making the condition difficult to recognize and diagnose," she told WBUR in August. The CDC says more than 110,000 suspected cases were identified in the U.S. from 2010 to 2022 and estimates that as many as 450,000 people may be affected.

A Positive Test Is Not a Diagnosis

The island numbers count positive blood tests, not confirmed cases. A positive result shows the body has made alpha-gal antibodies, but many people with a positive test never develop allergic symptoms.

Tufts University infectious disease professor Sam Telford stressed that distinction. "A positive test doesn't mean a confirmed diagnosis, and it doesn't mean a person will develop the allergy," he told WBUR. Telford said research suggests fewer than one-third of people who test positive go on to develop an allergy.

The rise in testing also inflates the count. The hospital ran far more tests in recent years as awareness grew, so some of the increase reflects more people being checked. Even so, island officials say the trend points to a real and growing problem.

Island health officials say better data is the first step toward a proportionate response. Tisbury health agent Drew Belsky said, "reportable disease data helps Boards of Health and our partners better understand the breadth of the problem."

Massachusetts made alpha-gal syndrome diagnoses and positive alpha-gal antibody tests reportable conditions in March 2026, joining 17 other states. Island tick epidemiologist Lea Hamner said the change will sharpen the picture. "Reportability allows public health to distinguish between a signal and true disease burden," she said in the Dukes County announcement.

Lone Star Ticks Push Into the Northeast

The lone star tick was historically most common in the Southeast and south-central United States. Telford told WBUR the species has been present on Cape Cod and Martha's Vineyard for more than two decades and that its populations have expanded significantly.

Islands with abundant deer and mild coastal winters offer good habitat, and ticks can spread with deer, birds, and other hosts. The CDC also notes that some alpha-gal cases have followed bites from blacklegged ticks, the species that spreads Lyme disease.

The burden is reshaping island life. In a June Vineyard Gazette report, restaurant owners described adjusting menus for diners who can no longer eat red meat, and a hospital physician assistant said some patients had talked about leaving the island altogether.

Researchers are now trying to learn who is most at risk. Martha's Vineyard Hospital and Mass General Brigham launched a two-year study following island residents bitten by lone star ticks. Hospital president Claire Seguin said "very little information is known about alpha-gal syndrome, how it behaves, who is likely to get it," according to the Gazette.

Reducing Tick Bites at Home and Outdoors

People who spend time in woods, tall grass or brushy yards in the Northeast and Midwest face the most exposure, including landscapers, hunters, hikers, gardeners, and children playing outdoors. Lone star ticks are aggressive biters that actively pursue hosts.

Telford recommended using repellent on legs, socks, and shoes and wearing long pants treated with repellent during extended time outdoors. Check your body and clothing after coming inside, shower soon after, and put clothes in a hot dryer to kill ticks. Keeping grass mowed and creating a dry border between lawns and woods can reduce ticks around the home.

Anyone who develops hives, swelling, stomach pain, or breathing trouble a few hours after eating red meat should talk to a doctor and mention any tick bites. Trouble breathing, throat swelling or fainting are signs of anaphylaxis and require emergency care.

Massachusetts health officials plan to release preliminary alpha-gal data later in 2026, WBUR reported. The bottom line: positive tests on Martha's Vineyard have soared since 2020 as lone star ticks spread, but a positive test is not a diagnosis, and preventing bites remains the most effective protection.

What Readers Want to Know

What is alpha-gal syndrome?

It is an allergy to alpha-gal, a sugar found in most mammals, that can develop after certain tick bites. People with it may react to red meat, dairy and some medications.

How many positive tests did Martha's Vineyard Hospital record?

The hospital recorded 572 positive alpha-gal tests in 2026 through August, compared with 742 in all of 2025 and two in 2020.

Does a positive test mean I have the allergy?

No. A positive test means your body made alpha-gal antibodies. Many people who test positive never develop allergic symptoms.

Which tick causes alpha-gal?

The lone star tick is most commonly linked to it in the U.S., though some cases have followed blacklegged tick bites.

What are the symptoms?

Hives, itching, swelling, stomach pain, nausea or breathing trouble, often several hours after eating red meat. Severe reactions need emergency care.

How can I reduce my risk?

Use repellent on legs, socks, and shoes, wear treated long pants outdoors, check for ticks after coming inside, and keep grass short around your home.