Published November 12, 2010, 12:00 AM

North Dakota deer tick tests positive for Lyme

Only 1 tick linked to disease so far
Researchers studying deer ticks in North Dakota have confirmed Lyme disease in one of the ticks captured during a research project that began last spring.

By: Brad Dokken, Forum Communications Co., INFORUM

Researchers studying deer ticks in North Dakota have confirmed Lyme disease in one of the ticks captured during a research project that began last spring.

The tick-transmitted disease can affect the skin, nervous system, heart and joints.

According to Nate Russart, a University of North Dakota graduate student working on the tick study, Lyme disease was confirmed in a single adult deer tick captured in Steele County. Researchers sampled 92 deer ticks, mostly in eastern North Dakota, and none of the other ticks tested positive for the disease, Russart said.

The study marks the first time deer ticks have been confirmed in North Dakota.

Relatively common in Minnesota, which has more of the forested habitat deer ticks prefer, Lyme disease remains uncommon in North Dakota. But more cases have shown up in recent years. According to the state’s Department of Health, North Dakota had 15 confirmed or suspected cases of Lyme disease in 2009, along with 11 cases in 2008, 12 cases in 2007 and seven cases in 2006.

From 2000 to 2005, North Dakota had no more than three cases, and there were no reports of Lyme disease in 2001, 2003 and 2004, the health department said.

Minnesota, by comparison, has had 900 to more than 1,200 Lyme disease cases since 2005, according to statistics from the state health department.

No surprise

Russart said he wasn’t surprised to find Lyme disease in one of the deer ticks. If anything, he said he would have expected more of the ticks to test positive.

“It might indicate the ticks have moved into the area, and the Lyme disease hasn’t yet, but that’s just speculation,” Russart said. “Our sample size isn’t really big enough to draw those kinds of conclusions.”

Dr. Jennifer Cope, an epidemiologist for the state Health Department in Bismarck, said the confirmed presence of deer ticks is the most important finding in the study so far. Even though tests found only one tick with Lyme disease, she said the presence of the ticks in North Dakota means there’s potential for more cases of the disease.

The goal, she said, is to educate clinicians who might not routinely diagnose Lyme disease to be on the lookout.

“The potential (for Lyme disease) is there; we have the vector, so that’s probably the most important message,” Cope said. “If treated early, it’s a very curable disease.”

Cope said additional research is planned for next year.

“We have a baseline now, and we’d like to get to different areas” to sample for deer ticks, she said.

The state Health and Game and Fish departments helped fund the study, which also includes researchers from North Dakota State University.

Russart said most of the deer ticks found were on the small mammals. Re­search­ers also captured hundreds of the larger, more common dog ticks, or wood ticks, which Russart said will be tested for other diseases. Wood ticks are known to carry diseases such as Rocky Mountain spotted fever, but not Lyme disease.

Russart said he also plans to test the deer ticks for other diseases.

Russart said he made two sweeps across the state collecting ticks, along with additional sampling closer to Grand Forks, and the deer ticks were most abundant in northeastern North Dakota.

Adult deer ticks are about half the size of a wood tick, and the nymph and larval stages are even smaller.

“There are deer ticks, and we have Lyme disease in the state,” Russart said. “There might not be a very high prevalence of it, but it’s possible, and people should make sure they check themselves after they’ve been outside.”

Brad Dokken writes for the Grand Forks Herald