Saturday, April 28, 2012

Tick Bite Can Turn Victim Vegetarian

A bite from one of these could end your carnivore days forever. Photo courtesy: John Tann/CC BY 2.0

Imagine breaking out in agonizingly painful and itchy red welts, or even anaphylactic shock, with no clear explanation about why it is happening. With careful logging of everything you eat or touch, the picture becomes more clear: eating meat triggers this misery. People with these symptoms are finding themselves faced with a choice: eat meat and suffer; or become vegetarian.

Fortunately for those inflicted by this mysterious allergy, one of the victims of this strange disease was Dr. Thomas Platts-Mills, a reknowned University of Virginia immunologist. Dr. Platts-Mills and his colleagues at UVA have been on a mission to figure out just what is going on. They reported initially in 2009 on what appeared to be a wholly new type of food allergy: cases of anaphylactic shock that were not occurring immediately after a food was eaten as is typical for food allergies, but which had its onset 3-4 hours after consumption of the trigger.

In the spring of 2011, the team of researchers came to an even more surprising conclusion: tick bites are causing meat allergies. The trigger turns out to be an oligosaccharide (a complex sugar, galactose-alpha 1,3-galactose or alpha-gal, if you like scientific names) contained in the cell on non-primate mammals -- that means a molecule that is in beef, pork, lamb, and other meats that is not found naturally in human cells. Alpha-gal in the tick's saliva sensitizes susceptible people when they are bitten; hives or anaphylactic shock result when the person subsequently ingests alpha-gal in meat.

The growing number of cases, as well as celebrity victim John Grisham, have recently raised the public profile of this allergy, which has been receiving reviews in the medical literature for several years already. Known cases largely follow the geographic range of the Amblyomma americanum, or the Lone Star tick, with a focal point in Virginia, but also including North Carolina, Tennessee, Arkansas, the lower half of Missouri and Australia, where doctors have associated another species of tick with meat allergies.

Not yet explained: Neither Lone Star ticks nor eating beef are new, so why are the reported cases of this allergy suddenly increasing? Have the ticks evolved a new component of their saliva recently? Are people more susceptible due to other confounding factors in their diets or lifestyles? Could changing climate in tick habitats be to blame?

While we do not recommend deliberately allowing white-spotted ticks to feast on you in hopes of finally breaking off your love affair with meat, you might want to look at it this way: if you convert to vegetarianism now, you won't need to worry about miserably itchy attacks of hives as a consequence of tick bites.

The Lone Star tick is just one more reason -- joining sustainable One Planet living, health benefits, and a warming sense of moral superiority -- for adopting a vegetarian lifestyle.

The Lone Star tick website gives great advice on how to recognize the male and female Lone Star ticks. True tick experts may note that the tick in the image has dressed up to better imitate the female Lone Star tick, recognizable by a single white "star" on the dorsal shield, a marking that is not shared by the male of the species.

In the meantime, be careful in the woods; and, use an environmentally- and people-friendly bug repellant.

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