Preventing Lyme disease

Bite of a deer tick can cause major headache.

The ticks are out.

Regular ticks are bad enough, scuttling into hidden niches on the human body and gorging themselves on blood. But their ick factor pales next to the danger posed by deer ticks, which can transmit Lyme disease.

A deer tick needs to be attached to the skin for 36 hours to transmit the disease; even then it’s easily treatable if caught promptly. But if untreated, symptoms include fatigue, fever and achiness; eventually, it can lead to nerve damage, joint pain.

Robert Sitko of Stillwater, Minn., a beekeeper who tends apiaries in the St. Croix River Valley and likes to go camping, knew he was at risk. One year, he saw the tell-tale bull’s-eye rash of Lyme disease on his body and went to a doctor, who prescribed three weeks of antibiotics.

That was that until a year later, when he ran a 105-degree fever and landed in the hospital. That time, it was anaplasmosis, also known as ehrlichiosis, another bacterium transmitted by deer ticks.

Now, Sitko does everything he can to avoid being bitten be a deer tick. He tucks his pants legs into his socks. He checks his skin and clothes religiously. He uses insect repellents. He might have taken the vaccine if it hadn’t been discontinued for human use, but he gets a shot of it for his German shorthair every year.

And after he found a deer tick while cutting trees in his back yard, he drove to REI and bought a canister of Permethrin clothing repellent. He can’t wait to use it.

“What you do is spray it on your clothes, let it dry two hours, and it’s supposed to last six weeks or six washings,’’ he said. “Supposedly, it kills ticks on contact. I thought, that’s the perfect thing for people going on a week’s camping trip.’’

Dr. Russell Johnson, a microbiologist who studies agents of Lyme disease University of Minnesota, says the product does work.

“It works very well,’’ he says. “In fact, it kills ticks within seconds of contact.’’

Depending on location, Johnson said, 40 to 60 percent of adult female deer ticks carry Lyme disease. The first ticks out mostly are adults; the nymphs that appear from mid-May to early July carry the disease at about half that rate, but all are looking for blood meals and are harder to see.

Deer-tick nymphs appear as black dots; adults are the size of a sesame seed. Western Wisconsin and the St. Croix Valley of Minnesota are considered hot spots for Lyme-carrying deer ticks, but they’re expanding their range northward and westward to the lakes region of Minnesota, he said.

To prevent infection, tuck in shirts and pants; ticks are easiest to see against light-colored clothing. Spray skin and clothing with bug spray containing 30 percent DEET, or spray clothing with Permethrin; an aerosol can that will spray three sets of clothing costs about $10. And check carefully.

Robert Sitko suggests running hands over skin to detect the smaller ticks. If you find one, pry it off gently with tweezers. Ticks also can hide themselves in folds of clothing and crawl onto the body later; Johnson says putting clothing in a dryer for 10 minutes will kill them.

About 80 percent of people will develop an even red rash that may look like a bull’s-eye rash, Johnson said. But even if you don’t, and you develop an unexplained fever or ache about two weeks after spending time in woods, consider the possibility of Lyme disease.

In 2006, 914 cases of Lyme disease were reported in Minnesota, says Melissa Kemperman, an epidemiologist with the state Department of Health, along with 177 cases of the more severe anaplasmosis and 18 cases of babesiosis, tick-borne disease caused by protozoa. About 25 percent of Minnesotans with Lyme picked it up in Wisconsin.

“We’re seeing all of these diseases increasing over time,’’ she says.

Last updated on May 7, 2008