Researchers looking at growing tick population and migration in Maine

Posted Aug. 23, 2011, at 9:01 p.m.

Deer ticks know how to travel.

The tiny hitchhikers have jumped aboard birds, rats, mice, humans and, of course, deer on their relentless 30-year journey north and east into every county in Maine, New Brunswick and Nova Scotia. Now, bites from infected deer ticks are causing between 900 and 1,000 people in Maine to be diagnosed with Lyme disease every year.

“If you’ve got the ticks, the deer and the mice, you’re going to have the potential setup for Lyme,” said Maine epidemiologist Dr. Stephen Sears.

The disease causes symptoms such as fatigue, headache, joint soreness, arthritis, neurological problems, heart problems and memory problems in sufferers.

Sears expects even more Mainers to become sickened in coming years. A map provided by the federal Centers for Disease Control shows how Lyme is spreading across the eastern seaboard and the upper Midwest. A thick band of blue dots indicating confirmed cases of the disease covers Connecticut, Rhode Island, Massachusetts and New Jersey. The thick band extends north only as far as midcoast Maine, with the rest of the state speckled with just a few blue dots. That potential for growth is one reason why Sears and the Maine Center for Disease Control are treating Lyme as a preventable disease, with heavy emphasis on public education.

“What can you do to know about Lyme disease and to prevent getting ticks?” he said. “It’s always better to prevent than to treat.”

Prevention

Experts say that common-sense tactics can help most people avoid getting bitten by ticks. Or, if they’re bitten, to more quickly seek treatment, as the sooner Lyme disease is treated, the easier it is to treat.

Meryl Nass, a physician with Mount Desert Island Hospital, had some tips for keeping safe. She said pesticides with 20 percent DEET are relatively effective against ticks, adding that some newer, less toxic pesticides also can work.

Nass sprays the bottoms of her pants and her shoes with pesticide before going hiking, avoids low-hanging branches and stays on the trails. Pulling socks over pants also helps, and hikers should always do a tick check after going outside.

But she cautioned against letting fear of Lyme disease deter people from getting fresh air, sunshine and exercise.

“The best thing for people is to be pretty careful — and to be careful enough so they won’t be worried about it,” she said. “We shouldn’t allow it to influence our lives; we should just be prudent.”

Jim Dill, a pest management specialist with the University of Maine Cooperative Extension, said he takes special care in the wood-grass interface where ticks are usually found. People can sweep their backyards for ticks by taking an old, fuzzy light-colored wool blanket and making it into a “tick drag.”

“You put it on a stick and drag that blanket in areas where kids are going to play, or in places where ticks will be,” he said.

But since ticks move around, people must keep dragging for them. Pesticides are a longer-lasting tick deterrent, and Dill recommended going to a local hardware store and asking for a yard-type pesticide.

“It is a terrible disease,” he said of Lyme.

Northern progress

When Dill was a boy playing in the central Maine woods years ago, he never had a tick on him. Back then, deer dicks were in such low numbers in the state they were practically nonexistent.

“Now, deer ticks are moving north,” he said.

Reasons for that include the fact that there are more deer in Maine and the general warming of the climate, which is better for ticks, Dill said.

But ticks don’t thrive in hot, dry conditions, as Maine had for much of last summer. According to the Maine CDC, which tracks confirmed cases of Lyme disease by county, there were 734 cases in Maine in 2010. There were nearly 1,000 cases the previous summer, which was notably wetter. While every county in the state has had confirmed cases, the numbers are much higher in the southwestern and midcoast counties and much lower in counties like Piscataquis, Aroostook, Somerset, Penobscot and Washington.

Scientists at the Maine Medical Center Research Institute in South Portland are working to track the tick migration.

Susan Elias, a research associate at the institute’s Vector-borne Disease Laboratory, said that researchers have been busy going into different towns and flagging for ticks during the first year of a climate-change study that has been funded by the federal Centers for Disease Control.

“The CDC is charged to look at how public health is affected by various examples of climate change,” she said. “You might have more heat waves, more heavy rainfall events, more variability. How will these factors affect public health? How will we expect increased heat or variability or rainfall to have an affect on tick abundance or tick range?”

A report based on research from the study’s first year should be completed later this fall, she said.

For more information about Lyme disease, please visit the website www.cdc.gov/lyme.

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