Tick-borne diseases are on the rise in Maine, the state’s top public health agency warned Thursday.
The Maine Center for Disease Control and Prevention said in a news release that so far this year it has recorded nearly 2,000 cases of Lyme disease, an inflammatory disease caused by a bacterium found in infected deer ticks. It’s one of the most common vector-borne illnesses — diseases transmitted to humans through the bite of an infected tick, flea or mosquito — with an estimated 30,000 new cases reported annually in the United States, according to the federal Centers for Disease Control and Prevention.
In its release Tuesday, the Maine CDC said this year it has also recorded nearly 700 cases of anaplasmosis, over 160 cases of babesiosis, 10 cases of hard tick relapsing fever and four cases of Powassan encephalitis.
“This is a record high for Powassan encephalitis cases,” the agency said. “Maine is also on track to break records for anaplasmosis, babesiosis and Lyme disease cases this year.”
That’s not to mention that the peak of tick season in Maine is the fall, Chuck Lubelczyk, an ecologist at the MaineHealth Institute for Research’s Vector-borne Disease Laboratory, said Thursday.
“In some ways, this is probably a preventative, cautionary press release, just warning people that there is still going to be a tick season going into the fall,” Lubelczyk said.
The answer to why tick-borne diseases are on the rise is not a straightforward one, said ecologist Griffin Dill, who manages the Tick Lab at the University of Maine Cooperative Extension in Orono.
“Part of it is just an increased awareness of (the threats that ticks pose), which increases, you know, the testing, which then of course increases the number of cases,” he said.
On the “ecological side” of things, milder, shorter winters in Maine allow ticks to emerge earlier in the season, and that gives them more time to feed on animals, like deer or the white-footed mouse, that carry the pathogens that cause these diseases, get infected and bite people or other animals, such as dogs.
“It’s these kinds of complex interactions between the climate, the hosts. Also, you know, we play a big role as well,” Dill said.
Maine being a highly forested state gives ticks plenty of space to thrive.
“And then we kind of mix in human development into those forested areas and we create this really nice edge habitat where our yard meets the forest. And it’s really great for mice, for chipmunks, for deer, for birds,” he said.
“And some of those hosts are really important to the ticks and then tick-borne pathogens and so we kind of create this perfect habitat for the ticks and their wildlife hosts,” Dill said.
Ticks are also going into new areas, Lubelczyk said.
“Every year, we have new communities where these ticks are being found as they expand northward and eastward.”
That’s partially due to the human development that Dill mentioned. But it also is partially due to what’s in the sky.
Every spring, migratory songbirds come up from South or Central America and on their way back to Maine, pick up ticks when they forage or nest in the ground in areas where there’s a higher prevalence of deer ticks.
“Essentially, really what it is, is these ticks are just hitchhiking on them as they’re flying up during migration,” Lubelczyk said.
“So what happens is year after year, you have a constant supply of these ticks being deposited. And eventually you get to the point where there are enough ticks to actually have a sustainable population of ticks,” and when they reach a certain threshold is typically when disease begins popping up, he said.
So what are Mainers, who love spending time outdoors, to do?
The Maine CDC recommends using EPA-approved tick repellents and wearing proper clothing while doing outdoor activities, like hiking, to reduce the risk of getting bitten by a tick.
Dill and Lubelczyk said people who spend time outdoors in tick habitats should get into the habit of doing tick checks on themselves and their companions, like a dog or a horse.
And finally, Lubelczyk said, there are several grounds maintenance measures property owners or entire communities can take on, such as keeping shrub layers down and picking up leaves in the fall.
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