Bite Out of Ticks

Baltimore Sun

Taking the bite out of ticks

Insecticide at deer feeders shows promise in killing carriers of Lyme disease

June 06, 2002|By Jason Song | Jason Song,SUN STAFF

The BB-sized tick could suck John Carroll's blood until it became the size of a bean, leave him with an angry red bite, and possibly give him debilitating Lyme disease to boot.

Carroll let it go.

"Don't squash it," he warned a visitor who was getting a little too close to the squirming insect Carroll released into the woods near Beltsville yesterday.

It is not that Carroll, a scientist who works at the U.S. Department of Agriculture's Beltsville research facility, is fond of ticks. After a decade of careful study, he can't think of anything good to say.

"They're really just out for themselves and the [diseases] they spread," he said.

But instead of killing, Carroll is counting juvenile tick larvae in an effort to measure the effectiveness of a new device that could drastically reduce the number of ticks and dangerous Lyme disease cases across the country.

"It's the only device we know of that gets [at] ticks on deer," said John George, a USDA scientist in Texas who is helping to oversee the project. "We think it will make a big difference."

In Connecticut, New York, New Jersey, Rhode Island and Maryland, scientists are conducting tick counts in locations where the new device is being tested to see if the experimental machine, which coats deer with a layer of insecticide, is working.

Deer ticks (Ixodes scapularis) are the primary carrier of Lyme disease, a stubborn and sometimes long-lived bacterial infection that has been on the upswing in the northeastern United States - including Maryland - over the last decade. Some Lyme victims say they suffer its effects for years.

The machine, which was invented by a team of Texas scientists, is baited with corn. To eat the corn, deer must push their head and shoulders between two paint-rollers that are coated with amitraz, an insecticide scientists say doesn't harm deer but will kill ticks.

While ticks attack every part of a deer, more than 90 percent are concentrated near the neck and face of the deer. And when a deer grooms itself, it will spread the insecticide to the rest of its body.

The devices, known as "four-poster feeders," have been placed in three sites in Maryland: Loch Raven in Baltimore County, Gibson Island in Anne Arundel County and Beltsville in Prince George's County. Scientists have been counting the number of ticks in the areas surrounding deer feeders and comparing them to control sectors that have no feeders.