What is Alpha-gal Syndrome?

The Mammalian Meat Allergy

What Is Alpha-gal Syndrome (AGS)?

Alpha-gal syndrome

(AGS), also known as mammalian meat allergy, is an allergy involving an IgE antibody response to galactose-α-1,3-galactose (1). This sugar, commonly known as alpha-gal, is found in all mammals except for Old World monkeys, apes, and humans (99). Its onset is associated with tick bites (3).

Alpha-gal syndrome was first described in 2009 (1). It is poorly understood within the medical community because of its recent discovery and its varied and atypical presentation. Reactions to alpha-gal are often severe and sometimes fatal. They can be immediate, as with hypersensitivity reactions to injected drugs, or delayed by 2 to 10 hours, as is typical after consumption of mammalian meat (1). Delayed-onset reactions often occur in the middle of the night (1).

Alpha-gal allergic reactions can occur after exposure to:

  • Mammalian meats, organs, and blood (57)
  • Dairy products, gelatin, and other foods derived from mammals (57)
  • Foods that contain mammalian byproducts (57)
  • Drugs, medical products, personal care, household and other products with mammalian ingredients (57)
  • Products containing carrageenan, which isn’t from a mammal, but which contains the alpha-gal epitope (54,57)
  • Flounder eggs (26), for reasons that aren’t clear

Alpha-gal

Galactose-α-1,3-galactose (alpha-gal or α-gal) is an oligosaccharide sugar.

  • Alpha-gal is a common component of mammalian glycolipids and glycoproteins and is found in the cells, tissues, and fluids of all mammals except for Old World monkeys, apes, and humans (58,70,93,94,95,96,97).
  • Some bacteria, protozoa (58), invertebrates (73), fungi (such as aspergillus) (73), and red algae (71) (including those used in the manufacture of carrageenan) (54), also express alpha-gal.
  • Many viruses incorporate alpha-gal into the glycoproteins of their envelopes (58).
  • Numerous human pathogens express alpha-gal (58).
  • Most non-mammalian vertebrates do not normally express alpha-gal, although it is found in cobra venom (58, 72) and possibly the eggs of some teleost fish (including flounder) and amphibians (26,58,74). There may be other exceptions as well (58,75).
  • Unlike proteins, alpha-gal is not denatured at normal cooking temperatures (70).

Symptoms→

Diagnosis→

Management→

A Paradigm-Shifting Allergy

AGS differs from typical allergies in significant ways:

  • AGS is associated with tick bites (3).
  • It is one of only two life-threatening carbohydrate allergies (4).
  • Its presentation is atypical and includes delayed-onset reactions that can occur 2-10 hours or more after exposure, often in the middle of the night (1,5,6).
  • Reactions do not occur after every exposure or follow an obvious pattern. This lack of consistency has been described as “almost a diagnostic hallmark” by experts (57).
  • Co-factors such as alcohol consumption and exercise can dramatically impact the severity of reactions or whether they occur at all (22,23,57).
  • In 3-20% of cases, patients report gastrointestinal symptoms alone, without other symptoms. Prior to diagnosis, many patients are misdiagnosed with IBS or other GI conditions (57).
  • Some patients present with arthritis (60).
  • AGS is associated more with adults than children, and onset in adults who previously tolerated red meat is common (57).
  • Hunters, foresters, and other populations with high exposure to ticks are more at risk of developing AGS (57,59,69,98). In some regions, twenty times as many people living in rural areas may be sensitized than people living in nearby urban areas (98).
  • The allergy component of AGS is only one dimension of a complex immune response that may have other health implications (7). Conditions tentatively linked to the alpha-gal immune response include some autoimmune diseases (7) and atherosclerosis (79,80).

“Unlike more traditional food allergies where consumption of an allergen produces symptoms within minutes, AGS reactions typically occur 3-8 hours after eating. Thus many patients fail to consider food as a possible trigger and many healthcare providers do not routinely recognize the characteristic delay–both issues can prolong tie to reach a diagnosis.” (57)

Dr. Scott P. Commins, MD PhD

University of North Carolina

“While GI complaints are not uncommon as part of an allergic reaction, 3-20% of patients with AGS report abdominal pain, nausea, emesis, diarrhea, or heartburn in isolation of cutaneous, cardiovascular or other signs/symptoms.” (57)

Dr. Scott P. Commins, MD PhD

University of North Carolina

“…there are also patients who have episodes of abdominal pain without any skin involvement. Those cases are a problem because the possibility of food allergy is not obvious, and they can be severe… Other diagnoses that arise less commonly are arthritis and chronic pruritis. Distinguishing [AGS] from chronic hives can be challenging.” (6)

Thomas Platts-Mills, MD

University of Virginia

An Emerging Epidemic

A Growing Threat

As tick populations swell and their ranges expand (3,9,10,15) the number of people being diagnosed with alpha-gal syndrome is rising (8).  Models suggest that this will continue (10,15).

  • AGS is already a common allergy in some regions of the world, including the U.S. (11), where the number of diagnosed cases has risen from 12 in 2009 to over 34,000 in 2019 (63).
  • The primary U.S. lab testing for alpha-gal IgE, ViraCor Eurofins, reported over 14,500 positive test results in a recent twelve-month period (81).
  • In populations with high exposure to ticks, 15-35% of individuals can be sensitized to alpha-gal (57). Even for people without the clinical symptoms of AGS, alpha-gal sensitization could be a risk factor for coronary artery disease (79,80).
  • In some areas, including much of the southeastern U.S., up to 3% of the population is estimated to have clinical AGS with anaphylactic reactions (57,61). The vast majority are undiagnosed or misdiagnosed with other illnesses.
  • People in rural areas and others in frequent contact with ticks, including foresters, hunters (57,59), loggers, and people with outdoor hobbies (15) are especially at risk.
  • AGS is the leading cause of adult-onset allergy and anaphylaxis throughout the South and much of the eastern U.S. (12).

Source: Olafson, P. Ticks and the mammalian meat allergy. USDA Beef Research, (2015)

Source: Bianchi J, Walters A, Fitch ZW, Turek JW. Alpha-gal syndrome: Implications for cardiovascular disease. Global Cardiology Science and Practice. 2020 Feb 9;2019(3).

At a threshold for positivity of 0.35IU/ml, up to 9% of people sensitized to alpha-gal have clinical alpha-gal syndrome with anaphylactic reactions after eating mammalian meat or organs (59). At the lower threshold for positivity of 0.1IU/ml, as few as 1% of people sensitized to alpha-gal have clinical alpha-gal syndrome (57). In populations with high rates of infection with endoparasites, sensitization to alpha-gal may be more common but less associated with clinical symptoms (18).

“The reported prevalence of individuals in the United States with elevated allergen-specific titers of anti-gal IgE (i.e. allergen positive) has been reported to be in the range of 8% to 46%, with highest prevalence within the geographic distribution of the Lone Star tick. Similar prevalence rates have been reported in other regions around the world.

Children within the geographic distributions of certain ticks are projected to have allergen positive prevalence comparable to the adult population. As one might expect, hunters and forest service workers have been reported to have a prevalence that is more than twice that of the general population. It appears that the prevalence of AGS equates to 10% of the allergen-positive population. Thus, in the southeastern United States, approximately 3% of the general population exhibits anaphylaxis after consumption of mammalian meat.” (61)

John Bianchi

Revivicor

A Leading Cause of Anaphylaxis

  • Roughly 60% of people with AGS have anaphylactic reactions (24,78,87,88,89) and 30-40% have cardiac and respiratory symptoms (90).
  • In one recent study of anaphylaxis, AGS was found to be the number one trigger, accounting for 33% of cases with a definitive cause. The number two cause was all other food allergies combined at 28% (44).
  • In the same study, recognition of AGS led to a reduction in the percentage of anaphylaxis cases without a definitive cause from 59% to 35% of total cases. (44)
  • In a second study, nine percent of all patients referred with unexplained anaphylaxis were found to have AGS (62).

Figure 1. Etiologies of anaphylaxis based on proposed definitive cause.Alpha-gal, galactose-a-1,3-galactose.

Source: Pattanaik D, Lieberman P, Lieberman J, Pongdee T, Keene AT. The changing face of anaphylaxis in adults and adolescents. Annals of Allergy, Asthma & Immunology. 2018 Nov 1;121(5):594-7.

A Lack of Physician Awareness

  • Due to its recent discovery, its unusual presentation, and lack of physician awareness, AGS is underdiagnosed and often misdiagnosed (13,14,57).
  • Diagnosis tends to be patient-driven, even in areas where AGS is prevalent (14).
  • Reports of occurrence are strongly influenced by the efforts of individual research groups and clinicians (15).
  • Many people with AGS who only have GI symptoms have had a colonoscopy, endoscopy, and/or cholecystectomy performed before being diagnosed (7).
  • In populations with high exposure to known vectors, AGS should be ruled out in cases of unexplained urticaria, angioedema, recurrent anaphylaxis, GI symptoms (7,82,83,84) and even arthritis (60).

Source: Flaherty MG, Kaplan SJ, Jerath MR. Diagnosis of life-threatening alpha-gal food allergy appears to be patient driven. Journal of primary care & community health. 2017 Oct;8(4):345-8.

Source: Flaherty MG, Threats M, Kaplan SJ. Patients’ Health Information Practices and Perceptions of Provider Knowledge in the Case of the Newly Discovered Alpha-gal Food Allergy. Journal of Patient Experience. 2020 Feb;7(1):132-9.

How Do You Get Alpha-gal Syndrome?

  • Alpha-gal syndrome is associated with the bite of certain species of ticks. In different parts of the world, different tick species are implicated (15).
  • In the United States, the Lone Star Tick (Amblyomma americanum) is thought to be the primary cause of AGS (16), based geographical range and tick salivary factors (57).
  • The Asian Longhorned Tick (Haemaphysalis longicornis), recently introduced in the U.S., is known to trigger AGS in Asia (19). As of yet, it has not been tied to any cases in the U.S.
  • Alpha-gal has been found in the saliva of Black-Legged Ticks (Ixodes scapularis) (8). It is possible that Black-legged Tick bites may trigger AGS, as do other species in this genus, but this has yet to be demonstrated.
  • The Cayenne Tick (Amblyomma cajennense), which is found in southern Texas and Florida (64), has been linked to cases of alpha-gal syndrome in Central America (65).
  • Limited data suggests that bee and wasp stings can cause a rise in alpha-gal IgE, but it has not been shown that they can drive the initial alpha-gal IgE response (57).
  • It is likely that additional tick species (8), possibly other ectoparasites (like chiggers (17) and mites (66)), and possibly even endoparasites (3,15,18) may be able to sensitize people to alpha-gal. Some may cause levels of sensitization too low to cause clinical reactions (5) and others likely induce full-blown AGS with anaphylactic reactions.
  • Only a small percentage of people who are bitten by ticks associated with AGS actually develop clinical symptoms (6).
  • Even if you have been bitten by ticks before and did not develop AGS, a future bite could trigger it (3).
  • Repeated tick bites are associated with a rise in alpha-gal IgE (20).
  • Multiple tick bites are associated with the onset of AGS (3). Many patients report that they were bitten by ticks for many years, and then after being bitten by multiple ticks at once, they developed alpha-gal syndrome.

Ticks and Alpha-gal Syndrome→

Avoiding Tick Bites→

What to Do If You Are Bitten by a Tick→

What is Alpha-gal Found in?

Alpha-gal in Foods, Drugs, Medical and Other Products

Mammalian Sources of Exposure to Alpha-gal

Alpha-gal is found in the meat, organs, tissues, cells, and fluids of all mammals except for humans, great apes, and Old World monkeys (1). It is also found in products made from mammals or that contain ingredients made from them (6,57). These include, but are not limited to:

Mammalian meat, organs, and other parts of mammals

These include some of the riskiest sources of alpha-gal. Examples include:

  • Mammalian meats (1), such as beef, pork, lamb, bison, venison, goat, horse, rabbit, squirrel, kangaroo, antelope, buffalo, camel, guinea pig, bats, whales, etc.
    • If you are not sure which animals are mammals, there is a guide here.
  • The internal organs of mammals, like liver (21), lung, heart, intestines (tripe), sweetbreads, and kidneys (6,57)
    • Internal organs can contain even more alpha-gal than meat  (22,23,24,25,26,27,94).
    • Some people who do not react to meat react after eating organs, like pork kidneys (24,59).
  • Mammalian gut sausage casings
    • Even turkey and chicken sausages often have these (6,57).
    • Removing the casing from chicken or turkey sausages and then eating the sausage without the casing is not advised, as this can lead to severe reactions. 
  • Mammalian fat, like lard, tallow, and suet
    • Mammalian fat is often in cooked foods, such as sauces, pastries, pie crusts, tortillas, tortilla chips, refried beans, baked beans, vegetable dishes, mashed potatoes, and desserts.
    • Some baking mixes (like Jiffy Corn Muffin Mix) contain lard.
    • Beef fat is often added to fry oil to enhance flavor (6,57).
  • Bones and bone marrow
  • Testicles (Rocky Mountain or prairie oysters)
  • Mammalian collagen (e.g. beef collagen sausage casings) (6,57)
  • Meat broth, bouillon, and stock (6,57)
  • Gravy (6,57)
  • Mammalian blood, found in soups, black pudding, blood sausage, blodplättar, and other foods
  • Meat extracts, like Bonox and Bovril
  • All other mammalian body parts, organs, tissues, cells, and fluids, such as tendons, brain, lungs, heart, nerves, skin, mammalian bile (Papait seasoning), and the products that contain them.

Most of the foods on this list should be avoided by everyone with alpha-gal syndrome. Many of us need to avoid all of them.

Rennet

Rennet is a complex set of enzymes that is used in the manufacture of some foods, such as cheese. Most rennet is extracted from the stomachs of ruminant mammals, although sometimes vegetable and microbial rennets are used. Some people with AGS can eat dairy products, as long as they don’t contain rennet from mammals.

Milk, other dairy products, and foods that contain them as ingredients (1,6,57)

Ten to thirty-three percent of people with AGS react to dairy products, especially those high in fat, like ice cream (6,57,85). A list of dairy products can be found here.

Gelatin and foods that contain gelatin (6,27,28,57)

Fewer than 10% of people with AGS react to gelatin in foods, although many more may have severe reactions after other types of exposure to gelatin, such as the intravenous administration of gelatin-based plasma volume expanders or gelatin-containing vaccines administered via intramuscular injections (6,57).

Natural flavors or flavorings

These are often beef or pork (57) and need to be avoided by many people with AGS. To find out whether the “natural flavors” in a product are derived from a mammal, contact the manufacturer. However, in the U.S., manufacturers are under no legal obligation to disclose the identity of ingredients that they call “natural flavors or flavorings.” Often, when asked, they will not disclose whether are derived from mammals or not.

Mammalian byproducts

An untold number of foods, especially processed foods, contain mammalian byproducts. There are hundreds of these byproducts often with obscure names, like oleic acid and monoglycerides. As of now, there is no comprehensive list of mammalian byproducts added to food in the U.S., much less information about their alpha-gal content. Most people with AGS do not react to mammalian byproducts in food, but some do (6,57), and severe reactions have documented (29). Further research is needed to determine alpha-gal content and safety of mammalian byproducts for people with alpha-gal syndrome (6,57). See our guide to mammalian byproducts here.

Cross-contamination

Some people with AGS react if their food is cross-contaminated by foods that contain alpha-gal, for example, if their poultry or seafood is cooked on a grill used for red meats (57).

Medications, vaccines, medical devices, and other medical products

Examples include:

  • Cetuximab (a drug that played a role in the discovery of AGS) (6,30,31,57)
    • Cetuximab has caused fatal reactions in people with AGS (86).
  • Other monoclonal antibodies (mAbs) produced in non-primate mammalian cell lines (6,57)
    • Evidence for alpha-gal expression on most of these mAbs, other than cetuximab, is minimal (6,57).
    • Exceptions include abatacept (57) and influximab (6,67)
  • Pancreatic enzyme replacements, such as pancrealipase and other enzyme replacements (6,36,57)
  • Thyroid hormones replacements (57)
  • Heparin (57)
  • Gelatin-based plasma expanders, such as Gelafundin, Gelofusine, Haemaccel (not commonly used in the U.S. if at all) (6,28,52,57)
  • Many vaccines, including those that contain gelatin or other mammalian byproducts. In the U.S., these include Zostavax, MMR, yellow fever, rabies, oral typhoid, FluMist and others (6,28,39,42,43,57,92)
  • Antivenom, such as crotalidae polyvalent immune Fab (CroFab) (6,50,51,57)
  • Bioprosthetic (bovine and porcine) heart valves (6,45,46,47,48,49,57)
  • Other products that contain gelatin, such as:
    • Hemostatic agents, such as Surgiflo (53) Floseal hemostatic matrix and Surgifoam powder (6)
    • Absorbable gelatin sponge (6), like Gelfoam
    • Gabapentin oral solution (6)
    • Lidocaine patch (6)
    • Gummy supplements (57)
    • Vaginal capsules (37)
    • Suppositories (28,87)
    • Collagen-containing agents, including implants (28,87)
    • Medications with gelatin capsules (6,57)
  • Many other perioperative, prescription, and OTC drugs  (32,33,34,35,57). Some of these pose a known risk to people with AGS; others contain mammalian-byproducts for which there is little data on alpha-gal content or their ability to contribute to clinical reactions, such as:
  • Many other medical products and devices, including (but not limited to) catgut sutures, lubricants, topicals, adhesives, etc. (6,32333435)
  • Some products used in dentistry

Airborne exposures

Some people with AGS report reactions to airborne forms of alpha-gal (57), including:

  • Suspended fat droplets in smoke or fumes from cooking meat, especially from grills
  • Other forms of airborne alpha-gal

Personal care and household products

Products containing “hydrolyzed protein” (gelatin), lanolin, glycerin, collagen, and tallow tend to be the most problematic. Hundreds of additional mammalian ingredients whose alpha-gal content is unknown are also added to personal care and household products, including:

  • Skin care products, including lotion
  • Hair products, such as shampoo and conditioner
  • Make-up
  • Deodorants and antiperspirants
  • Liquid soaps and other cleansers
  • Toothpaste
  • Hand sanitizers
  • Latex condoms
  • Personal lubricants
  • Perfumes
  • Toilet paper, which is sometimes impregnated with gelatin
  • Many cleaning products
  • Dryer sheets made with lanolin– these are problematic for many of us, triggering both airborne reactions and rashes.
  • Detergents and fabric softeners, such as Downy fabric softener
  • Crayons

“Due to the parenteral route of administration, allergists consider alpha-gal-containing drugs even more dangerous for allergic patients than mammalian meat.” (91)

Jörg Fischer, et al.

Carrageenan

The food additive carrageenan is made from red algae, not mammals, but contains the alpha-gal epitope (54). At least 1-2% of people with AGS react to carrageenan (57). Some people with AGS report severe carrageenan reactions with rapid onset. Read about our reactions to carrageenan here.  Products that can contain carrageenan include, but are not limited to:

Foods

  • Many dairy products including ice cream; milk shakes, like Dairy Queen blizzards; yogurt; flavored, evaporated, and condensed milk; whipped topping; cheese; and sour cream (76)
  • Many dairy-free substitutes (57)
  • Desserts, including custard, flan, pudding, mousse, sorbet, gelato, and gel desserts (76,77)
  • Drink mixes, such as powdered lemonade (77)
  • Juice (76,77)
  • Ready to spread icing (76,77)
  • Jams and jellies (76,77)
  • Candy (76,77)
  • Salad dressing, mayonnaise, and relishes (77)
  • Poultry and poultry products (77)
  • Drinks, such as beer and juice clarified by carrageenan  (77)
  • Seafood, such as fish treated with carrageenan to improve moisture retention  (77)
  • Infant formula  (77)
  • Tofu (77)

When carrageenan is used as a processing aid, for example when it is used to clarify beer and juice, as a spray on fresh cut fruit, or on fish to aid in retention of moisture, manufacturers are not required to list it on the label.

Medications other medical products

We have limited information about carrageenan in medications and medical products, but it appears to be used in:

Personal care and household products:

  • Many toothpastes
  • Liquid soaps and other cleansers
  • Skin care products
  • Hair products
  • Make-up
  • Air fresheners
  • See the Environmental Working Group’s Skin Deep database for more information about personal care products that contain carrageenan.

As many red seaweeds contain carrageenan (71), it’s possible that other forms of edible red algae may also contain the alpha-gal epitope.

 Other Potential Sources of Alpha-gal

Limited data suggest that some foods that do not obviously contain mammal or red algae derived ingredients can cause reactions for reasons that aren’t clear. These include:

  • Flounder roe (eggs) (26)
  • Possibly other types of fish roe (58,74)
  • Canned tuna (6)

What Is a Mammal?→

Mammalian Byproducts→

Carrageenan→

Checklist for the Newly Diagnosed→

What Foods Do Not Contain Alpha-gal? 

As far as we know, alpha-gal is not typically found in:

  • Fish or seafood (58) except for possibly flounder eggs (26) and maybe even the eggs of other teleost fish (58)
  • Birds, like chicken, turkey, quail, and emu (58)
  • Reptiles, like snakes, crocodiles, and lizards (58)
  • Amphibians, like frogs, except for cobra venom and possibly some amphibian eggs (58)
  • Plants, including fruits, vegetables, and grains
    • Note that algae are not plants, and some red algae (seaweed) do contain alpha-gal.
  • Edible fungi, like mushrooms

Poultry sausages may have casings made from the intestines of mammals.

Some of these foods–especially chicken, turkey, and seafood–may be injected, treated or sprayed with mammalian substances or carrageenan or otherwise contaminated by them. These may be listed among the ingredients, but if they are considered a processing aid, as with gelatin used to clarify juice and wine or carrageenan sprayed on cut fruit or fish, they will not be.

Flounder eggs trigger reactions in people with alpha-gal syndrome (26). It’s not known whether this is because they contain alpha-gal, cross-reactive glycolipids, mimetic peptides, or for some other reason.

Some people with AGS report reacting to canned tuna (6) for reasons that are not clear but which may be related to the use of processing agents or fillers.

There are unverified, anecdotal reports of people with AGS reacting to chicken eggs when the chicken are not fed a vegetarian diet. Eggs from chickens fed a vegetarian diet and duck eggs seem to be better tolerated.

In general, the less processed your food, the less likely it is to contain alpha-gal. Read labels and buy from trusted sources. Be careful when eating out. Cooking your own food will help you avoid alpha-gal.

More Information

Help Find a Cure→

Physician Experts→

Research Publications Database→

References

1. Commins SP, Satinover SM, Hosen J, Mozena J, Borish L, Lewis BD, Woodfolk JA, Platts-Mills TA. Delayed anaphylaxis, angioedema, or urticaria after consumption of red meat in patients with IgE antibodies specific for galactose-α-1, 3-galactose. Journal of Allergy and Clinical Immunology. 2009 Feb 1;123(2):426-33.

2. Commins S, Lucas S, Hosen J, Satinover SM, Borish L, Platts-Mills TA. Anaphylaxis and IgE antibodies to galactose-alpha-1, 3-galactose (alphaGal): insight from the identification of novel IgE ab to carbohydrates on mammalian proteins. Journal of Allergy and Clinical Immunology. 2008 Feb 1;121(2):S25.

3. Commins SP, James HR, Kelly LA, Pochan SL, Workman LJ, Perzanowski MS, Kocan KM, Fahy JV, Nganga LW, Ronmark E, Cooper PJ. The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-α-1, 3-galactose. Journal of Allergy and Clinical Immunology. 2011 May 1;127(5):1286-93.

4. Soh JY, Huang CH, Lee BW. Carbohydrates as food allergens. Asia Pacific Allergy. 2015 Jan 1;5(1):17-24.

5. Levin M, Apostolovic D, Biedermann T, Commins SP, Iweala OI, Platts-Mills TA, Savi E, van Hage M, Wilson JM. Galactose α-1, 3-galactose phenotypes: Lessons from various patient populations. Annals of Allergy, Asthma & Immunology. 2019 Jun 1;122(6):598-602.

6. Platts-Mills TA, Li RC, Keshavarz B, Smith AR, Wilson JM. Diagnosis and management of patients with the α-Gal syndrome. The Journal of Allergy and Clinical Immunology: In Practice. 2020 Jan 1;8(1):15-23.

7. Commins SP. Invited commentary: alpha-gal allergy: tip of the iceberg to a pivotal immune response. Current allergy and asthma reports. 2016 Sep 1;16(9):61.

8. Crispell G, Commins SP, Archer-Hartman SA, Choudhary S, Dharmarajan G, Azadi P, Karim S. Discovery of alpha-gal-containing antigens in North American tick species believed to induce red meat allergy. Frontiers in immunology. 2019 May 17;10:1056.

9. Monzón JD, Atkinson EG, Henn BM, Benach JL. Population and evolutionary genomics of Amblyomma americanum, an expanding arthropod disease vector. Genome biology and evolution. 2016 May 1;8(5):1351-60.

10. Raghavan RK, Peterson AT, Cobos ME, Ganta R, Foley D. Current and future distribution of the lone star tick, Amblyomma americanum (L.)(Acari: Ixodidae) in North America. PLoS One. 2019 Jan 2;14(1):e0209082.

11. Wilson JM, Platts-Mills TA. Red meat allergy in children and adults. Current opinion in allergy and clinical immunology. 2019 Jun 1;19(3):229-35.

12. Commins, SP. (2018). Retrieved from: More people developing red meat allergy from tick bites. CBS News

13. Flaherty MG, Threats M, Kaplan SJ. Patients’ Health Information Practices and Perceptions of Provider Knowledge in the Case of the Newly Discovered Alpha-gal Food Allergy. Journal of Patient Experience. 2020 Feb;7(1):132-9.

14. Flaherty MG, Kaplan SJ, Jerath MR. Diagnosis of life-threatening alpha-gal food allergy appears to be patient driven. Journal of primary care & community health. 2017 Oct;8(4):345-8.

15. Cabezas-Cruz A, Hodžić A, Román-Carrasco P, Mateos-Hernández L, Duscher GG, Sinha DK, Hemmer W, Swoboda I, Estrada-Peña A, De La Fuente J. Environmental and molecular drivers of the α-Gal syndrome. Frontiers in Immunology. 2019 May 31;10:1210.

16. Commins SP, Platts-Mills TA. Tick bites and red meat allergy. Current opinion in allergy and clinical immunology. 2013 Aug;13(4):354.

17. Stoltz LP, Cristiano LM, Dowling AP, Wilson JM, Platts-Mills TA, Traister RS. Could chiggers be contributing to the prevalence of galactose-alpha-1, 3-galactose sensitization and mammalian meat allergy?. The journal of allergy and clinical immunology. In practice. 2019 Feb;7(2):664.

18. Arkestål K, Sibanda E, Thors C, Troye-Blomberg M, Mduluza T, Valenta R, Grönlund H, van Hage M. Impaired allergy diagnostics among parasite-infected patients caused by IgE antibodies to the carbohydrate epitope galactose-α1, 3-galactose. Journal of Allergy and Clinical Immunology. 2011 Apr 1;127(4):1024-8.

19. Chinuki Y, Ishiwata K, Yamaji K, Takahashi H, Morita E. Haemaphysalis longicornis tick bites are a possible cause of red meat allergy in Japan. Allergy. 2016 Mar;71(3):421-5.

20. Hashizume H, Fujiyama T, Umayahara T, Kageyama R, Walls AF, Satoh T. Repeated Amblyomma testudinarium tick bites are associated with increased galactose-α-1, 3-galactose carbohydrate IgE antibody levels: a retrospective cohort study in a single institution. Journal of the American Academy of Dermatology. 2018 Jun 1;78(6):1135-41.

21. Bianchi, John (2019). Personal communication

22. Morisset M, Richard C, Astier C, Jacquenet S, Croizier A, Beaudouin E, Cordebar V, Morel‐Codreanu F, Petit N, Moneret‐Vautrin DA, Kanny G. Anaphylaxis to pork kidney is related to I g E antibodies specific for galactose‐alpha‐1, 3‐galactose. Allergy. 2012 May;67(5):699-704.

23. Fischer J, Hebsaker J, Caponetto P, Platts-Mills TA, Biedermann T. Galactose-alpha-1, 3-galactose sensitization is a prerequisite for pork-kidney allergy and cofactor-related mammalian meat anaphylaxis. Journal of allergy and clinical immunology. 2014 Sep 1;134(3):755-9.

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