LEWISTON — Maine is getting warmer and wetter. Bugs like that.

A lot.

And diseases like bugs.

In some parts of Maine this year, experts say, up to half of the deer ticks are expected to carry Lyme, a potentially serious infectious disease caused by bacteria. Forty Mainers have been diagnosed in 2016 so far — and most of that time it’s been winter.

Lyme isn’t the only thing bugging Maine.

Cases of tick-spread infectious diseases have been growing in recent years. Mosquito-borne illnesses such as West Nile virus and eastern equine encephalitis are moving into the state, and researchers believe more diseases will come as the climate continues to warm.

“It’s a common (belief) that the most deadly animal in the world is the mosquito, and I’m sure that’s literally true,” said Monroe Duboise, a University of Southern Maine associate professor of applied medical sciences, who has studied vector-borne diseases — those transmitted by bugs.

Experts say Mainers shouldn’t fear going outside, but as the climate warms they should take precautions: Use insect repellent, wear long pants and long-sleeved shirts, stay out of bug-infested areas when possible.

And get used to it.

“We’re just keeping an eye out for anything coming our way,” said Maine State Epidemiologist Siiri Bennett. “Things do spread. Whether it’s mosquitoes or squirrels, they don’t really stop at the state boundary.”

Warmer, wetter, great for opossums
Between 1895 and 2014, Maine warmed 3 degrees, according to Maine’s Climate Change Future 2015 Update, a report produced by the Climate Change Institute and Maine Sea Grant at the University of Maine.
During that same period, Maine’s annual precipitation increased by 6 inches, a 13 percent jump, most of it rain in summer and fall. Snowfall decreased by an inch. 
Climate change is complex, affected by both human actions and the whims of Mother Nature. Even in the midst of that warming trend, there were cold years, many attributed to major volcanic eruptions.
There will likely be such cool periods again — the climate doesn’t change in a straight line — but “overall, the warming’s probably going to continue,” said Maine State Climatologist Sean Birkel, co-author of Maine’s Climate Change Future update.
That report predicts Maine will warm another 3 to 5 degrees by 2054 and towns throughout Maine will see far more days in which the heat index hits 95 degrees or higher. Lewiston will triple from five 95-plus-degree days a year to 15.
By 2050, precipitation is expected to increase by 1 to 7 percent, depending on the region. Most of that will be rain. By 2054, Southern Maine is expected to lose over 40 percent of its snowfall, while central Maine will lose 20 to 40 percent and northern Maine will lose less than 20 percent.  

Since the early 1900s, Maine has seen its winter shorten and summer lengthen by two weeks. Experts predict that will happen by another two weeks between 2035 and 2054, which means Maine’s summer will be a full month longer than it used to be.

That warmer, wetter weather has a very real impact on the critters Mainers are used to seeing — or not seeing.

“Opossums are kind of our classic example of a new species that’s shown up, especially in Southern Maine,” said Nate Webb, wildlife biologist for the Maine Department of Inland Fisheries and Wildlife.   

Once virtually unheard of in Maine — they’re prone to frostbite in cold weather — opossums are now common in parts of the state. It’s possible that other, more exotic, creatures could soon be, too.

“That’s something that we’ve had to really keep a close eye on,” Webb said. “We haven’t seen that with venomous snakes yet, but certainly the red-eared slider, which is a turtle species, is now established in several locations in Maine. That’s something nobody ever really thought could become established this far north. It turns out that they are capable of surviving here.” 

It’s the same with bugs.

Lyme skyrockets

Extremely cold temperatures kill both ticks and mosquitoes, but Maine is getting warmer. The bugs, and the diseases they carry, are increasingly at home here.

The deer tick, with the Lyme disease it often carries, is by far the most prominent, and growing. In 2001, Maine reported 108 cases of Lyme. In 2014, it reported about 1,400 cases. Part of that increase is likely due to better awareness and diagnosis.

Last year’s numbers aren’t final, but Bennett, with the Maine Center for Disease Control and Prevention, said preliminary figures show about 1,200 cases for 2015. It’s the first time in years Maine has seen any kind of a dip.

“One theory is that the winter of 2014 to 2015 was very severe and it lasted a long time. It was a very late spring, so in fact the summer season was quite short,” Bennett said. “So it may be that we didn’t see a real increase in cases because the season was so short.”

That’s good news for last year. Maybe not so good news for this one.

“You look at a year like now, where perhaps our season is starting early, there is a potential there for again having an increase in the number of cases. We don’t know,” Bennett said.

Lyme has been reported in every county in the state. It is most prevalent in Southern and coastal Maine, where Lyme disease maps show a blanket of blue, each tiny, colored dot representing a single case. Islands have also been hard hit by Lyme. The disease is spreading in Central, Western and Eastern Maine. 

Griffin Dill, integrated pest management professional and tick ID program coordinator for the University of Maine Cooperative Extension, believes one-quarter to one-third of Maine’s deer ticks will carry Lyme this year, depending on the region.

“In some cases it could be as high as 50 percent or more,” he said.  

Other serious tick-borne illnesses are increasing in Maine, too. Babesiosis, a parasitic infection that attacks the red blood cells and can cause life-threatening complications, grew from nine cases in 2011 to 55 in 2015. Anaplasmosis, a bacterial infection that can also be life-threatening, grew from 26 cases in 2011 to 186 in 2015.

Mosquito-borne diseases aren’t as prevalent. While ticks can burrow under snow to stay warm enough to survive winter, a single hard frost can kill off mosquitoes.

But Maine’s summers are getting longer and wetter, which mosquitoes like. Even tropical mosquito-borne diseases are moving into the Northeast. 

Once unheard of in Maine, there have been two human cases of eastern equine encephalitis, or EEE, since 2014. There have also been two human cases of West Nile virus.

The Maine CDC watches for the mosquitoes that carry those diseases and others.

“We start testing and trapping in certain areas in July to sort of see what sort of mosquitoes we’re seeing,” Bennett said. “We don’t have a huge program because of resource limitation, but we do some of that trapping here in Maine. We do watch what’s happening in places like New York and Massachusetts very closely. If they start to see certain things coming through, then of course we’re more on the alert. They will tend to move up.”

What else could be coming? According to some researchers, possibly the mosquito that carries the Zika virusdengue fever and chikungunya virus.

“The maps that were drawn, I think, two or three years ago probably would have put the time of arrival at about the middle of the century,” said Duboise at USM. “I think that timeline would be reassessed some at this point and very likely that could be optimistic. They could arrive sooner.”

He’s thinking in a few years.

“The odds are pretty good,” he said. “Or pretty bad.”


Maine isn’t alone. Vector-borne diseases and climate change are a worldwide problem and they’ve gotten both national and international attention. According to the World Health Organization, more than 1 billion people are infected and more than 1 million people die from vector-borne diseases each year.

Earlier this week, the Obama administration moved $589 million from other projects, including fighting Ebola, to tackle the Zika virus. 

Maine lawmakers have pushed for funding to fight vector-borne diseases, especially Lyme. 

“Lyme disease is a problem that is growing really quickly and we need to get ahead of it with more research and better data,” said Maine’s 1st District congresswoman, Democrat Chellie Pingree, who sits on the U.S. House Appropriations Committee and helped create a $5 million research program at the Department of Defense focusing on tick-borne diseases.

On the ground in Maine, state officials monitor both tick and mosquito populations, as well as the animals that those bugs like to feed on. For Lyme-carrying ticks, that means the white-tailed deer. 

As the Maine Department of Inland Fisheries and Wildlife tries to balance competing priorities — disease concerns versus the positive aspects of wildlife — the department is asking Mainers what they want to do about deer management, especially in areas with a lot of Lyme.

“It’s a factor,” Webb said. “It’s really up to the public to tell us as managers how important they think that factor should be in management decisions.”

There are few vaccines to prevent vector-borne diseases in humans. Although one was developed in the late 1990s to protect people against Lyme, its manufacturer withdrew it from the market after three years because of declining sales and consumers’ fears over vaccine side effects.

Researchers around the world continue to work on vaccines for diseases carried by insects. Some are just starting to look into an anti-tick vaccine that could be widely given to wildlife — like the white-tailed deer in Maine — to prevent the bugs from feeding and continuing their life cycle.

“However, it’s very ‘Star Trek’ and it’s probably quite a ways off before that’s ever going to be deployed in a useful fashion,” said Chuck Lubelczyk, vector ecologist with the Maine Medical Research Institute. “That’s sort of the Holy Grail of  vaccine development.”

In the meantime, experts say, Mainers can take steps to protect themselves:

* Get rid of the places bugs live. For mosquitoes, that means used tires (the most common site for mosquito breeding in the United States) and standing waterFor ticks, that means Japanese barberry shrubs, bittersweet vines, leaf and brush piles and overgrown grass. 

* Be aware of your surroundings. Don’t go into areas most likely to harbor ticks, such as off hiking trails.

* Make sure window and door screens are intact to stop bugs from coming inside.

* Use bug repellent when outside. The U.S. Centers for Disease Control and Prevention recommends repellents that use DEET, picaridin, IR3535 or oil of lemon eucalyptus.

* Dress to stop insect bites. That means wearing a hat, long-sleeved shirt and long pants tucked into socks. Light-colored clothing helps you spot ticks more easily. 

Check yourself, your children and your animals after being in areas that could be infested with ticks. Some diseases, such as Lyme, can only be transmitted after the tick has been attached for many hours. 

* If you find a tick attached, carefully remove it and save it in a plastic baggie (with rubbing alcohol or placed in a freezer) for identification.  

“The best way to protect yourself is to not be bitten in the first place,” said Bennett with the CDC. “That’s the bottom line.”

There is one bit of good news.

“Opossums are very well-known to love eating ticks,” said Maine Audubon staff naturalist Doug Hitchcox.

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