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Over 500,000 Americans are now allergic to red meat because they were bitten by a tick

In a peculiar twist of events, people in the United States have developed an allergy to red meat since 2010, triggered by tick bites.

This syndrome is known as alpha-gal syndrome. Because it is is still largely unknown to most people, health officials speculate that the number of affected individuals could be significantly higher.

The Centers for Disease Control and Prevention released two reports co-authored by Dr. Scott Commins, a researcher from the University of North Carolina. One report suggests that over 500,000 Americans may have developed the allergy, ranking it as the tenth most prevalent food allergy in the country.

While no deaths have been confirmed as a result of alpha-gal syndrome, sufferers have described the allergy as baffling and deeply distressing. “I never connected it with any food because it was hours after eating,” said Bernadine Heller-Greenman, a sufferer of the syndrome, in an interview with the Associated Press.

What is alpha-gal syndrome?

Alpha-gal syndrome isn’t caused by a pathogen. Instead, it’s the result of a sugar, alpha-gal, found in the meat of mammals and the saliva of ticks. When alpha-gal enters the body through the skin, as happens with tick bites, it triggers an immune response which can lead to a severe allergic reaction.

Researchers established the initial link to this syndrome when patients reacted to a cancer drug, made from mouse cells that contain the alpha-gal sugar. By 2011, researchers discovered that it could also spread via tick bites.

The lone star tick, which is most prevalent in the eastern and southern parts of the U.S., was identified as the primary culprit. Roughly 4% of all reported U.S. cases originated from the eastern side of New York’s Long Island.

A recent study scrutinized the test results from the main U.S. commercial lab that searches for alpha-gal antibodies from 2017-2022. The results revealed an increase in positive tests from around 13,000 in 2017 to 19,000 in 2022.

Most doctors are unaware of alpha-gal syndrome

Experts theorize that the uptick in cases could be due to the lone star ticks’ expanding territory, increased human-tick interactions, or an increased awareness and testing for the syndrome by medical professionals.

Unfortunately, not all doctors are knowledgeable about the syndrome. In a survey of 1,500 U.S. primary care doctors and health professionals, nearly half were unfamiliar with alpha-gal syndrome.

Only 5% felt extremely confident in their ability to diagnose it. These findings were used to estimate the total number of individuals with the allergy – about 500,000.

Recognizing and managing the symptoms

Symptoms of alpha-gal syndrome can include hives, nausea, vomiting, diarrhea, severe stomach pain, difficulty breathing, dizziness, and swelling of the lips, throat, tongue, or eyelids. Unlike many food allergies, which surface immediately after eating, reactions from alpha-gal syndrome occur several hours later.

The American Gastroenterological Association advises those experiencing unexplained diarrhea, nausea, and abdominal pain to be tested for the syndrome.

The current approach for managing this condition involves dietary adjustments, carrying epinephrine for emergencies, and avoiding tick bites. About 15% to 20% of Dr. Commins’ patients have experienced the dissipation of the allergy. However, avoiding re-infection from tick bites is crucial.

“The tick bites are central to this. They perpetuate the allergy,” Dr. Commins explained to the Associated Press.

Among Dr. Commins’ patients is Bernadine Heller-Greenman. The 78-year-old New York art historian recently found herself suffering from the syndrome.

Doctors diagnosed her with alpha-gal syndrome after she experienced several episodes of severe allergic reactions. Since avoiding red meat, dairy products, and ticks, Heller-Greenman has not experienced any further allergic reactions.

Despite the difficulties, Heller-Greenman remains optimistic, stating, “I feel very lucky, really, that this has worked out for me. Not all doctors are knowledgeable about this.” By vigilantly monitoring food labels with her grandchild, she has adapted to her new reality.

More about ticks and tick bites

Ticks (subclass Acari) are small arachnids, closely related to spiders and scorpions. Ticks are among the most potent disease vectors in the world, transmitting a wide range of harmful pathogens to humans and animals alike through bites.


Ticks are part of the phylum Arthropoda, class Arachnida, and subclass Acari. The subclass divides into two families: Ixodidae (hard ticks) and Argasidae (soft ticks). The hard ticks have a hard shield on their dorsal surfaces, while soft ticks do not. Combined, these families contain over 800 species of ticks.


Ticks differ from other arachnids due to their unique external structure. Adults usually possess a small, egg-shaped body, with a hard, shield-like structure (scutum) on the dorsal side in the case of hard ticks. They have four pairs of legs, a pair of palps, and a specialized feeding apparatus known as the hypostome, used for penetrating the host’s skin.

Ticks are sexually dimorphic, with females generally larger than males. Female ticks can increase dramatically in size when engorged with a blood meal.

Life cycle

A tick’s life cycle comprises four stages: egg, larva, nymph, and adult. Ticks require a blood meal to transition between each stage. The life cycle can take anywhere from months to years, depending on the species and environmental conditions.

Tick eggs hatch into six-legged larvae, which seek and feed on a host, usually a small mammal or bird. After feeding, the larva detaches and molts, transforming into an eight-legged nymph. The nymph repeats the feeding process, this time on a larger host. After the second molt, it becomes an adult tick, which can feed on a range of hosts, including humans.

Feeding habits

Ticks are obligate hematophagous (blood-feeding) parasites. Ticks bite using their hypostome to pierce the skin of their host.

They secrete saliva containing anesthetic compounds to avoid detection by their hosts. This process allows them to feed undisturbed, often for days.

Ticks employ two main strategies for finding hosts: questing and ambushing. In questing, ticks climb grasses or shrubs and stretch their front legs out, waiting for a potential host to pass.

They use heat, moisture, and vibrations to detect hosts. Ambushing ticks, on the other hand, reside in nests or burrows and attack hosts directly.

Disease transmission

Ticks play a significant role in transmitting diseases to humans and other animals. When they feed, ticks can transfer various bacteria, viruses, and parasites from their saliva into the host’s bloodstream.

Lyme disease, caused by the bacterium Borrelia burgdorferi, is the most common tick-borne illness in the Northern Hemisphere. Other diseases transmitted by ticks include Rocky Mountain spotted fever, Tularemia, Babesiosis, Ehrlichiosis, and Tick-borne encephalitis.

Tick-borne diseases often present similar initial symptoms, such as fever, muscle aches, and rash. The exact course of illness varies depending on the specific pathogen involved. Prevention and early detection are key in managing tick-borne diseases.

In summary, ticks are resilient arachnids with a life cycle intricately tied to their environment and host organisms. They are known for their ability to transmit numerous diseases. This makes them a public health concern worldwide. Understanding ticks, their habits, and their habitats can aid in minimizing their impact on human and animal health.

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