Ticks as Predators
Ticks don’t fly, and they don’t blow in the wind. They live in tall grass and either crawl up or fall onto their hosts. People who spend lots of time outdoors in the summer are generally told to avoid ticks by wearing long clothing or spraying on lots of bug repellent, but Dr. Thomas Mather (Tick Encounter Resource Center, University of Rhode Island) says neither is the best method of protection.
“Those are the tips you typically find in women’s magazines,” he said. “We know people aren’t going to do this. They’re not going to want to wear long pants in the summer. They’re not going to want to tuck their pants into their socks.
“Most people don’t want to cover themselves with bug spray, and bug repellent with DEET really doesn’t work. It does a good job of keeping mosquitoes away. Not ticks, though. Just because it says it on the can, doesn’t mean it works.”
So how do you avoid ticks? Mather’s Tick Encounter Resource found that covering shirts, shorts (yes, shorts) and shoes, inside and out, with a bug repellent called permethrin does the trick.
Last year, Mather and colleagues did a two-day test using 15 volunteers, half with treated clothing, half with untreated clothing, and unleashed hundreds of blood-sucking ticks onto them.
What they found was that people in the treated clothing were 71 percent less likely to have living ticks attached to their clothing at the end of the test period. Dead ticks cannot transmit disease, Mather said.
They also found that ticks exposed to permethrin-treated clothing died within 10 to 20 seconds of contact.
The tough part, Mather said, is finding permethrin, which is commonly sold only in sporting good stores. Permethrin must be spread onto clothing 48 hours before it’s worn, and it is not recommended for spraying directly onto the skin.
Why So Much Interest in Lyme Disease?
The most feared tick-borne illness is Lyme disease, which is spread by ticks so small that they often go unnoticed and is named for the Connecticut town where Yale researchers first traced the disease back to insects.
Marc Siegel, an internist and FOX News contributor, said other tick diseases don’t receive as much attention, and for good reason.
“They’re not as common as Lyme disease,” Siegel said. “It’s also because we tend to target certain health concerns in the media, and Lyme disease has gotten a lot of attention because we have a deer problem. And when people see deer, they think of Lyme disease.”
Unlike other tick diseases, Lyme disease is seen in most areas of the U.S. But it’s most common in the Northeast.
New England and Mid-Atlantic states average more than 17,000 cases of Lyme disease annually, according to the interactive map found on the Tick Encounter Resource Web site.
The Mountain region of the U.S. averages just 20 cases annually, while the Pacific region averages 104 cases.
If caught early, Lyme disease is curable, Siegel said. But if it’s diagnosed late, it can become a chronic condition.
“You have to weigh the enjoyment of being in the outdoors with the risk,” Mather said.”This is particularly important in the Northeast, where the black-legged tick is so common and Lyme disease can be debilitating and even cause death.”
Siegel said early detection, which will prevent Lyme disease from becoming a chronic condition, should be the focus.
People who find ticks on themselves should remove them immediately with a sharp pair of tweezers. Square tweezers will not do the trick, Mather said, because they are likely to leave a portion of the tick in the skin. Ticks should also be pulled straight out, not twisted.
Siegel suggested bringing the tick to a physician to have it tested for disease. “If it tests positive for Lyme disease, I always treat with antibiotics,” he said. “If it tests negative, you don’t have to worry about it.”
Five Tick Diseases to Watch For:
Lyme Disease: Spread by the black-legged or deer tick, this disease is most common in the Northeast. Symptoms include a circular rash at the site of the tick bite, tiredness and neurological and facial muscular problems.
Rocky Mountain Spotted Fever: Common to the Southeast, symptoms of the disease include sudden onset of fever, headache and muscle pain, followed by development of rash. The disease can be difficult to diagnose in the early stages, and without prompt and appropriate treatment it can be fatal.
Ehrlichiosis: Common to the Southwest, this disease is spread by the lone star tick and is carried by dogs, cattle, sheep, goats, and horses. Symptoms include a fever and swollen lymph nodes.
Babesiosis: This disease is carried by deer ticks and is found most often in the Northeast and upper Midwest. Symptoms include a nonproductive cough, headache and increasing malaise.
Human Granulocytic Anaplasmosis: HGA is increasingly recognized as an important and frequent cause of fever after tick bite in the upper Midwest, New England, parts of the mid-Atlantic states and northern California, according to the Centers for Disease Control and Prevention. Other symptoms include headache and malaise.
Dr. Thomas Mather, a professor of public health entomology and director of the Center for Vector Borne Disease and Tick Encounter Resource Center at the University of Rhode Island, said tick problems tend to have a regional focus.
“Kind of like how on The Weather Channel you’ll see a map and it will be hot in one region, stormy in another,” he said.
If there were a Tick Channel, and it showed a map of the country, viewers might see tick-borne diseases such as Lyme disease, babesiosis and human anaplasmosis plaguing the Northeast, Mid-Atlantic and upper Midwestern regions of the U.S., Mather said.
In the Southeast, you would see some Lyme disease and lots of Rocky Mountain fever. In the Ozark Plateau, home to states like Missouri and Arkansas, you’d see Rocky Mountain spotted fever and ehrlichiosis. In the Western region, there’d be more Lyme disease and Rocky Mountain fever.
Mather said the prevalence of tick diseases on a particular region depends on the types of ticks found there and the animals they most commonly feed off of. In the Northeast, for example, the black-legged or deer tick is most prevalent and feeds off of rodents and deer, carriers of Lyme disease.
The Western black-legged tick, like its name, is found in the West. It tends to feed on livestock, which carry Lyme disease and Rocky Mountain spotted fever.
The American dog tick spreads Rocky Mountain fever in the Midwest and feeds off of dogs, cattle, deer, raccoons, and opossum.
The wood tick, found in the West, is the culprit that caused the Washington state boy’s tick paralysis. In the U.S., it’s rare to see this disease in humans, Mather said.
“You’re more likely to see it in animals,” he said. “You might have dog that shows a sudden lameness, and that could be tick paralysis. It’s more common in humans in Australia.”
The odd thing about tick paralysis, Mather said, is that once the tick is removed, the disease goes away and usually requires no further treatment.
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