They’ve been in the New York Times. They’re all over National Public Radio. They are tucked in the pages of National Geographic. They might be crawling up the back of your leg right now. Ticks! Ticks are everywhere!
This is not the first time I have addressed ticks in these pages. In the November/December 2008 issue of Massage & Bodywork, I published an article on tick-borne diseases, with a special emphasis on Lyme disease (“Tick-Borne Diseases,” page 107).
Now that these creatures are in the news again, it is time to revisit the topic.

A Tick Primer

The United States is home to about 90 species of ticks, and as I was writing this article, another headline emerged about a new species—the Asian longhorn tick—that has been found all along the US Eastern seaboard and as far west as Arkansas. This species is of interest because in Asia it causes an infection with a 15 percent mortality rate. This has not been observed in the United States yet, but it’s something to watch.
Ticks are arthropods, which simply means they have exoskeletons and jointed legs. They are in the same class of animals as mites, including the mites that cause scabies. Ticks are ectoparasites: they live on the surface of their hosts, while they feast on that animal’s blood—sometimes in such numbers that they can weaken or even kill it. Ticks’ hosts are usually mammals, but some ticks prey on reptiles or amphibians.
In addition to being bloodsuckers, ticks can be disease vectors, spreading pathogens from animal hosts to human hosts. This is how the bacterium that causes Lyme disease is spread, as well as the microorganisms responsible for ehrlichiosis, babesiosis, tularemia, and several other diseases.

A new condition

Recently a new tick-related condition has emerged. This one isn’t related to a pathogen that infects humans. Instead, this situation involves a massive and potentially deadly allergic response to a component of the saliva of lone star ticks. This species is most prevalent in the southeastern United States, although they have now been found as far north as Maine and as far west as Minnesota. The problem is, the triggering substance in lone star tick saliva is also found in meat from almost every mammal. The net result: people who are sensitive to this molecule, and who are bitten by the right tick, become allergic to meat.

Tick Bites and Meat Allergies

The connection between tick bites and the development of meat allergies is a recent phenomenon. It has been tracked for about 10 years, although the first recorded instances may date to the 1990s when a group of patients in a drug trial for colorectal cancer developed symptoms triggered by the gel caps of their medications.
It took several years, but scientists eventually associated the geographical distribution of previously healthy adults who suddenly developed extreme allergic reactions to meat with the distribution of Rocky Mountain spotted fever—an infection spread by lone star ticks. This led them to look for allergic markers related to tick bites, and the discovery of a new phenomenon: tick-triggered mammalian meat allergies.
The allergen in this situation is a sugar molecule called galactose-alpha-1,3-galactose, but scientists use the term alpha-gal. Alpha-gal is found in the cell membranes of all mammals, with the exception of most primates. It is a component of beef, pork, lamb, and game meats, but it is not found in poultry. If someone is sensitive to this molecule, the condition is called alpha-gal syndrome.
Alpha-gal gets into the human bloodstream when an affected lone star tick regurgitates into its host. A reaction may develop within a few weeks after only one tick bite, but repeated exposures appear to make immune system reactivity to alpha-gal more extreme.
In alpha-gal syndrome, the body suddenly begins to make a big immune response to the alpha-gal that occurs naturally in ingested meat. A widespread immune system response develops when alpha-gal molecules cross from the intestines into the bloodstream. The result usually involves a delay of several hours, followed by digestive discomfort, a rash, extreme itching, swelling, and a dangerous drop in blood pressure—in short, life-threatening anaphylactic shock.
The only treatment for alpha-gal syndrome is to avoid all mammalian meat. This also includes any substances or medications that use meat products. Many people find they have reactions to milk, butter, cheese, and other dairy products too. However, with time, this extreme allergic reaction may subside. After a couple of years, many people with alpha-gal syndrome find they can rebuild tolerance for some meats, especially lean cuts that are prepared without fats.
Interestingly, lone star ticks are not the only species that can trigger this reaction. The same response is seen in Australia, Japan, Sweden, and several other countries, with ticks endemic to those regions. In fact, this situation is so common in Australia (often as a reaction to kangaroo steaks) that EpiPens there are carried for meat allergies more often than for any other type of allergic reaction.

Questions? Lots!

Does all this make you curious? You’re not alone. This situation has piqued the interest of many researchers and allergy specialists. Here is a short list of the most burning questions and possible answers—any of which may change as we learn more about the ticks, their saliva, and our immune system responses.
Why is there a response to alpha-gal from ticks, but not from a lifetime of meat eating?
Many people are exposed to alpha-gal from eating meat for decades without any immune system reactivity. Then, something happens to make the susceptible person’s immune system response to alpha-gal much more extreme. Scientists theorize that other chemicals in tick saliva may heighten the immune system reaction and trigger the body to react to alpha-gal from all sources.

Does everybody who gets bitten by a lone star tick get alpha-gal syndrome?

No. Even if the same tick bites two people, it is not a guarantee that both people will develop an allergy to alpha-gal. Why? That may be a matter of individual immune system functionality. It has been observed that people with type A or O blood and a history of multiple tick bites are more likely to have this kind of reaction than others.

Why is this happening now? What has changed?

This is a very complex question with many possible answers. It may be that there are simply more ticks and tick bites than in previous years, so the percentage of the population with alpha-gal syndrome is growing. Or it may be due to changes in human gut microbiomes—our internal environment is less capable of dealing with allergic stimuli due to antibiotic use, low exposures to environmental triggers, and other factors. Another possibility is that the same numbers of people are being exposed to this trigger, but an increasing portion of them are proceeding to develop allergies—again, for reasons that are not clear. Finally, we could be seeing a reflection of changes to the ticks’ microbiomes as well as our own. And of course, it could be a combination of any or all of these possibilities.

How is this different from other allergies?

Alpha-gal syndrome is unique in several ways. First, it seems to come on with a specific and extreme onset in people who never had allergies to meat before—this is different from the pattern seen in most allergies, which usually begin in childhood and persist into adulthood. Also, this food-based allergy is triggered by a sugar molecule; almost every other food allergy is related to proteins. The allergy-causing antibodies are peculiar in alpha-gal syndrome too. Alpha-gal can trigger the production of several types of antibodies, and not all of them lead to big reactions. For some reason, it appears that the immune system switches what kind of antibodies it uses in alpha-gal syndrome, and this leads to the most severe immune system response. Lastly, alpha-gal syndrome is different because for most people it seems to subside within a few years—this is not a typical allergy pattern.

Is there a connection with other disorders?

One of the most fascinating lines of inquiry about alpha-gal syndrome is that it may be a factor in the inflammatory processes that support the deposition of atherosclerotic plaques. In the United States, the Southeast (where lone star ticks are most common) has the highest incidence of heart disease and stroke—it is sometimes called the “stroke belt.” Is there a connection? And what does alpha-gal syndrome tell us about other possible symptoms or syndromes? It is possible that many other conditions are related to tick bite or other vector-related reactions, and this insight may open the door to new and more effective prevention and treatment options.

Tori’s Story

Tori Stafford is a 21-year-old student at the University of Tulsa. Two years ago, Tori was spending an evening with a friend. She’d had a few bites of meatloaf around 5:30 p.m. At 8:30 p.m., they intended to go run an errand at a store, but Tori’s stomach was “messed up,” so she decided to go home instead. She got into her car and within moments, she says, “I was so itchy—my ears, the bottoms of my feet, my eyes were itching so bad I couldn’t drive.” Over the next few minutes, her symptoms got worse. Her friend convinced her to go to the ER. In the 15 minutes it took to get there, she had become itchy all over. Her lips and throat were swollen, she was shivering, and it was hard to breathe.
They gave her Benadryl, and three hours later she was released to go home, with a recommendation that she see an allergist. She did, and her blood work plus prick tests revealed alpha-gal hypersensitivity: extreme allergies to beef, pork, lamb—“anything on four legs.” Tori was skeptical, but when her allergist asked her about her outdoor activities and she remembered a tick bite from a few months before, Tori was convinced her meat allergy was real.
Unlike many people with this condition, Tori can enjoy dairy products, so ice cream is still accessible to her—we agreed that this is a significant factor in her quality of life. Now, two years later, she is slowly introducing meat back into her diet. The chances are good that Tori will fully recover from this reaction.
Implications for Massage Therapy Practice
What does all this have to do with massage therapy practice and making choices for the session room? Probably not a lot—except that our clients sometimes tell us things they don’t tell their doctors. Also, our healthy regular clients probably see us more often than they see their primary care providers. So, if someone reports an episode like Tori’s, with a surprising and sudden onset of itching, swelling, and difficulty breathing, we may be able to steer them in the right direction for an important diagnosis. Note: this is not to suggest that we should ever say anything even vaguely like, “Wow, sounds like a meat allergy—try avoiding meat for a while and it will probably go away.” I hope that is very clear.
Getting some background information on tick-induced meat allergies may not make substantial differences in your practice, but the curiosity this condition may spark is good for all of us. We live in an amazing, fascinating world. We live in amazing, fascinating bodies. We can share that amazement and fascination and appreciation in every interaction with our clients.

Resources

Abcore. “Allergy Antibodies.” Accessed September 2018. www.abcore.com/allergy-antibodies.
Aubrey, Allison. “Red Meat Allergies Caused by Tick Bites Are on the Rise.” NPR.org. June 25, 2018. Accessed September 2018. www.npr.org/sections/thesalt/2018/06/25/621080751/red-meat-allergies-caused-by-tick-bites-are-on-the-rise.
Gibbens, Sarah. “A Tick Bite Could Make You Allergic to Meat—and It’s Spreading.” National Geographic. June 21, 2017. Accessed September 2018. https://news.nationalgeographic.com/2017/06/tick-bite-meat-allergy-spreading-spd.
McNeil, Donald G., Jr. “An Invasive New Tick Is Spreading in the U.S.” The New York Times. August 6, 2018. Accessed September 2018. www.nytimes.com/2018/08/06/health/asian-long-horned-tick.html.
National Institutes of Health. “NIAID Scientists Link Cases of Unexplained Anaphylaxis to Red Meat Allergy.” November 28, 2017. Accessed September 2018. www.nih.gov/news-events/news-releases/niaid-scientists-link-cases-unexplained-anaphylaxis-red-meat-allergy.
Paules, Catharine I. et al. “Tickborne Diseases—Confronting a Growing Threat.” New England Journal of Medicine. July 25, 2018. Accessed September 2018. https://doi.org/10.1056/NEJMp1807870.
Velasquez-Manoff, Moises. “What the Mystery of the Tick-Borne Meat Allergy Could Reveal.” The New York Times. July 24, 2018. Accessed September 2018. www.nytimes.com/2018/07/24/magazine/what-the-mystery-of-the-tick-borne-meat-allergy-could-
reveal.html.