Lone Star Tick Turns Meat Eaters into Vegetarians
When meat eaters convert to become vegetarians, it can happen in one of two ways: they make the choice themselves, or the choice is made for them. It appears that people who are bitten by the lone star tick can end up in the second category, as has been reported recently regarding a rash of tick bites in Virginia.
Yes, you can be allergic to meat
Some vegetarians have kiddingly told carnivores they are allergic to meat, and while their remarks are often a way to circumvent criticism from meat eaters, it turns out people can be allergic to meat. A meat allergy is known as galactose-alpha-1,3-galactose (alpha-gal), and it is believed to affect more than 1,500 people in the United States, although the exact number is difficult to determine and it could be rising given the recent rise in tick bites.
The meat allergy was originally discovered by a team of researchers led by Thomas A. Platts-Mills and Scott P. Commins at the University of Virginia Health System. In their 2009 article in the Journal of Allergy and Clinical Immunology, they reported how IgE (immunoglobulin E) antibodies to alpha-gal were found in 24 patients who had experienced anaphylaxis (severe, life-threatening allergic reaction) or hives after eating beef, pork, or lamb.
Individuals with alpha-gal have elevated levels of IgE, and the higher the IgE, the more severe the allergy. Platts-Mills is intimately familiar with the meat allergy, after being bitten numerous times by the ticks.
Meat allergy is unique
While having a meat allergy is uncommon, what is also unusual about this food allergy is that it is caused by sugar and not a protein, as are most other food allergies. Yet another novelty concerning meat allergy is that it has been linked to the bite of the lone star tick (Amblyomma americanum), which is commonly found in Virginia, but can also be found throughout the United States, especially among the eastern, southeastern, and south central states.
Alpha-gal is different from other food allergies in that anaphylaxis is delayed for four to six hours after the individual has eaten the offending food. Other food allergies, such as those to peanuts, shellfish, and eggs, typically occur within seconds to minutes of eating the food item.
This characteristic makes alpha-gal an especially dangerous allergy, because individuals may be sleeping, driving, or in any number of other situations when the severe allergic reaction occurs. That reaction could be deadly unless victims are prepared to give themselves an epinephrine injection immediately.
According to Commins, there may be an organisms in the tick's saliva that makes people who have been bitten by the insect to become allergic to the alpha-gal sugar found in meat, as he commented in a CNN report.
Combating a meat allergy
Although people with the meat allergy can combat it by injecting themselves with epinephrine after sitting down to a steak dinner, such a measure is likely too extreme for most people. Commins did note that some people who have been bitten but who avoid subsequent bites by the lone star tick may become less allergic to meat over time.
The only way to discover if one's reaction to meat has lessened, however, is to eat meat or have a food challenge and wait for a reaction. A food challenge is a method used by a doctor (usually an allergist) in a controlled environment to determine if a food allergy exists or to confirm a food allergy.
The optimal way to conduct a food challenge is when neither the doctor nor the individual with the allergy knows whether the food or capsule consumed contains the allergen. Such testing needs to be done several times and patients must be observed for any reaction.
According to the Centers for Disease Control and Prevention, the lone star tick (so named because of the single dot on the female's back) has been increasing its numbers, range, and distribution over the past few decades. They can be aggressive and will feed on humans as well as on dogs and cats, who can also bring the ticks into the house.
A bite from a lone star tick can cause rash, headache, joint or muscle pains, swollen lymph nodes, and fever within 30 days of receiving the bite. Apparently it may also turn a meat eater into a vegetarian.
Centers for Disease Control and Prevention
CNN: Ticks causing mysterious meat allergy
Commins SP et al. Delayed anaphylaxis, angioedema, or urticaria after consumption of red meat in patients with IgE antibodies specific for galactose-alpha-1,3-galactose. Journal of Allergy and Clinical Immunology 2009 Feb; 123(2): 426-33
Image: Wikimedia Commons