The lone star tick, native to the Southeast but spreading to the north, is a distinctive-looking tick, so named because of the single white dot on its back. Unlike black-legged (deer) ticks, lone star ticks don't transmit Lyme disease, the bacterial illness that can wreak havoc on people's nervous systems, but they do transmit other tick diseases, namely ehrlichiosis, a bacterial disease that can be fatal if not treated properly.
It also appears that their saliva carries an antibody that causes the immune system to overreact in the presence of sugars found in red meat, leading to an allergic reaction that usually shows up as itchy, burning hives all over your trunk and back.
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"Meat allergies are not very common," says Thomas Platts-Mills, MD, professor of medicine and head of the division of Allergy and Clinical Immunology at the University of Virginia Medical Center, and the doctor who stumbled onto this discovery. "And this is truly the first example we've found of a food allergy being cause by a bug bite."
He discovered the relationship after doing some research into why people were having allergic reactions to a cancer drug that was introduced in 2005. Nearly 20 percent of people receiving the drug developed hives after their injections, similar to those experienced by people with meat allergies. The drug contained the sugar found in meat. All of the reactive people had the antibody carried by the lone star tick. But he didn't know the tick was the vector until he himself was bitten and noticed his levels of that particular antibody spiked. After he started asking his meat-allergic patients if they'd been bitten by ticks prior to becoming allergic to meat, 90 percent reported that they had.
"Have we proven that ticks are the cause in a formal, scientific sense? No," says Dr. Platts-Mills, "but I'm 99 percent positive that they are." He published his findings in the Journal of the American Academy of Allergy, Asthma and Immunology.
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Dr. Platts-Mills thinks that lone star tick larvae could also be vectors for this allergy. Most people know their larvae by their more colloquial name, chiggers—tiny critters that burrow under your skin and itch like crazy. And he's also interested at looking at other biting insects, such as biting black flies and no-see-ums, to determine whether their bites could transmit food allergies.
Meat allergies are difficult to diagnose. It usually takes between three and five hours for the body to have an allergic reaction, and in some people, the allergy will go away not long after a tick bite, while in others, the allergy could persist for up to 20 years, Dr. Platts-Mills says. "We can't predict accurately how long it will last," he says, and subsequent tick bites could make it worse. "We've seen some people [whose antibody levels] are going lower, then they get a bunch of tick bites, and they're way higher." He also notes that African Americans seem more susceptible to the allergy-creating bites.
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Your best bet? Just avoid ticks—especially if you love red meat. Here are some commonsense ways to cut down on tick-bite risk:
• If you've spent time outside—even in your yard—take a shower as soon as you go into the house. Research has shown this tactic to be very effective in knocking ticks off of your body before they can attach and transmit disease (or food allergies!).
• If you live near woods or a meadow, install a strip of gravel between your yard and those habitats. First of all, ticks don't like crossing rocky surfaces. But since gravel also cuts down on the mice that run into your yard, the ticks have more difficulty coming into your lawn and garden without rodents to catch a ride on over that rocky area.
• Mow your grass regularly, as tall grass and brush are a tick's favorite hiding spots.
• Keep woodpiles in bright, sunny locations. Ticks don't like hot or dry conditions, but they love wood, and wood in shaded areas is a perfect home for them.
• Tuck your shirt in and tuck your pants into your socks on long hikes, to keep ticks from crawling inside your clothing. Insect repellents containing DEET are the most effective chemical protection against ticks, but they're also toxic. Only as a last resort when you're in areas with heavy tick populations should you use them, and apply them only to your clothes, not to exposed skin.