Ticked Off: Maine Lab Tracks Growing Impact of Disease-Carrying Pests

Aug 25, 2014

A deer tick.
Credit File photo / MPBN

SCARBOROUGH, Maine - Twenty-five years ago, a critter about the size of a poppy seed grabbed the attention of a few researchers at Maine Medical Center. It was the deer tick - a tiny creature that carries a potentially devastating illness: Lyme disease. The researchers formed the Vector-borne Disease Lab to learn more about where deer ticks occur in Maine and about how they spread disease. A quarter of a century later, the lab is as busy as ever. Patty Wight has the first of two stories on the work being done there.

If you're at all creeped out by ticks, you need to get over it quickly at Maine Medical Center's Vector-borne Disease Lab. Diagrams of ticks effectively serve as wallpaper. There's a giant inflatable tick on the wall, a furry stuffed one in an office, and vials and vials of the real guys.

"That's probably 1,000 there, and maybe 500 there, and we've got a freezer full of DNA and tick bodies," says Research Assistant Susan Elias, one of five staffers at the lab who handle ticks that come through the door, either from the lab's own work in the field or from other scientists in New England. The job of the Vector-borne Disease Lab is to identify these ticks and check them out for disease. They do this, says Elias, either by dissecting ticks or grinding them up and extracting DNA.

"We did some educational programming for fifth graders awhile back, and I had one little girl raise her hand and say, 'Miss Elias, how did you get such a disgusting job?!' " she says.

But to Elias, the work fascinating.  It's about piecing together a story of why deer ticks are in Maine, where to find them, and how best to control them.

Vector-borne Disease Laboratory founders Dr. Robert Smith, left, and Dr. Peter Rand.
Credit Patty Wight / MPBN

At about 50 research papers and counting, says lab co-founder Dr. Rob Smith, it's a growing story. "I don't think anybody predicted the tick would become abundant in so many different habitats or environments, and certainly not in northern New England," Smith says.

It turns out, Maine offers prime real estate for ticks. Migratory birds bring them in. Rodents, deer, and damp wooded vegetation make them stay. There are 14 species of ticks in the state, but researchers at the Vector-borne Disease lab focus on deer ticks because in Maine that's the only kind that transmits diseases to humans.

"Nobody predicted that this tick could carry several different organisms," Smith says. "We're now up to five different pathogens that have been recognized that deer ticks can carry and transmit to people" - potentially serious diseases, such as babesiosis and anaplasmosis that are treatable with antibiotics, and the rare but deadly Powassun virus, which claimed the life of a Maine woman last year.

While the lab has helped to identify some of these pathogens, it's a more difficult chalalenge to control them. "I think we have to be pretty humble about our understanding in general because these are complicated infections, and lots of different factors can cause one to become more prominent."

But Maine's islands offer unique laboratories that provide some answers. The lab worked with Monhegan Island in the late '90's to eradicate its abundant deer population, and cases of Lyme disease dropped to almost zero, says lab co-founder Dr. Pete Rand.

"The question is, though, how far do you have to go to reduce a deer population in order to break the cycle?" Rand says. "We and others think that may be 10 deer per square mile or less."

Lab researchers have also found ornamental shrub species like Japanese barberry and honeysuckle are favorite homes for ticks. The lab was also the first to find that a botanical pesticide made of rosemary oil is just as effective at killing ticks as a chemical spray. But for all that they've learned, there's still a long way to go, says Dr. Rob Smith.

"When you look at this on a population basis, there have not a lot of success stories, in terms of preventing these diseases," he says, "even though we think we know how to do it."

And that's because it has not been easy making the public aware and concerned enough to take preventative measures - wearing long sleeves and pants and using repellant. But that's just one of the things the Vector-borne Disease Lab is working on, as it continues to tell the story of ticks in Maine.

Tomorrow we'll hear about the Vector-borne Disease Laboratory's work on mosquito-borne illnesses.