Tick season is in full swing in Maine, and so far, weather conditions have been favorable for these dangerous pests. This may not bode well for the months ahead.
“The real kicker is that it’s been a very damp spring, and the damp helps ticks survive,” said Chuck Lubelczyk, a field biologist for the Maine Medical Center Research Institute’s Lyme and Vector-Borne Disease Laboratory. “If it stays damp and rainy as it has been, we can expect a fairly normal to healthy season for ticks.”
In addition, Maine just experienced a relatively snowy winter, with snowfall above average throughout the state. Snow protects and insulates overwintering ticks, helping them survive the cold months.
“I think we had enough snow cover over the winter that winter conditions probably didn’t have any impact on tick populations,” said Griffin Dill, pest management specialist at the University of Maine Tick Identification Lab. “We’re not anticipating reduced tick numbers or reduced tick activity [this year].”
Nevertheless, a hot, dry summer could slow down tick activity in the state, Lubelczyk said. Maine’s most troublesome tick — the blacklegged tick, also known as the deer tick — is highly susceptible to drying up and will seek shelter in dry conditions rather than search for animals — or people — to bite.
“This time of year it’s tricky because the growing season is just starting, and once the trees start to green out, they’ll pull an awful lot of the moisture out of the soil,” Lubelczyk said. “If we end up running into the situation that we’ve had the past couple of years where we have dry conditions starting in June and lasting through August, that’s not a good situation for ticks. The next few weeks is going to be very telling.”
A new tick in Maine
To date, 16 species of ticks have been identified in Maine, but for years, people have only worried about one species: the blacklegged tick. The sole vector for Lyme disease, the blacklegged tick has bitten and infected thousands of Maine residents.
But there’s another tick crawling northward that Mainers may soon have to be concerned about.
The lone star tick, common throughout the Southeast, recently became established as far north as Connecticut and Cape Cod, Massachusetts. This species — which was named for the white star shape visible on the female’s back — can carry and transmit a number of dangerous pathogens to people. Their bite can also cause people to become allergic to red meat.
“We don’t at this point think it’s established in Maine,” Lubelczyk said, “but we’ve been looking.”
That’s not to say lone star ticks haven’t been seen in Maine. They have but so far, researchers have been unable to verify that any breeding populations exist. They believe the lone star ticks found were transported by migrating birds.
“A lot of the lone star ticks that come into our lab are related to someone who’s been traveling out of state,” Dill said. “That said, we do get a handful of them a year from people who pick them up in Maine. They’re making it to the state, but the real question is whether they can persist and make it through the winter here. That’s still unclear.”
Compared to blacklegged ticks, lone star ticks are larger, hardier and less vulnerable in dry environments. They also seek hosts differently. The blacklegged tick and American dog tick — both of which are common throughout Maine — “quests” for hosts by perching on grass blades or other vegetation and waiting to latch onto animals that pass by. The lone star tick, on the other hand, pursues hosts more aggressively. The species will actually move across the landscape, albeit slowly, in pursuit of prey, responding to carbon dioxide and movement.
“With these ticks, when they get established, it’s a real game changer because they’re very successful at repopulating and come in big numbers where they’re found,” Lubelczyk said of the lone star tick. “They carry different pathogens [than Maine’s other ticks] and are a serious pest on livestock, so they’re an agricultural concern as well.”
New tick-borne diseases in Maine
In Maine, Lyme disease has long been the most prevalent and concerning tick-borne disease. Carried and transmitted by the black-legged tick, this disease often starts out with flu-like symptoms, and if not treated with antibiotics, it can progress to affect the joints, nervous system and other organ systems.
But that’s not the only tick-borne disease that Maine residents should be aware of.
In the past five to 10 years, Maine has seen a steady increase in the number of reported cases of two other diseases that are transmitted by the black-legged tick: anaplasmosis and babesiosis.
“We’ve seen some of the same pattern in other states,” Dill said. “It seems like Lyme disease kind of comes in first and has this steady increase in the number of cases, and then anaplasmosis comes in behind it, and then babesiosis.”
In addition, Maine researchers are keeping an eye on Rocky Mountain spotted fever, a tick-borne disease carried and transmitted by the American dog tick, a species that is common throughout Maine. Currently, researchers believe that Maine’s population of American dog ticks don’t carry the disease.
“We’re actually working on a panel [lab test] that will hopefully have finished in the next month or so to be able to test dog ticks and some other ticks known to be vectors of that pathogen so we can start doing surveillance and figure out if its occurring here and at what magnitude,” Dill said.
In 2019, there have been 10 probable cases of Rocky Mountain spotted fever in Maine, but all or some of those cases could have been from ticks picked up while people were traveling out of state. Currently, most cases of this disease are reported from North Carolina, Tennessee, Missouri, Arkansas and Oklahoma.
“[In addition to affecting humans] it’s also a canine pathogen, so if it were here, we’d likely see it in the veterinary community first,” Lubelczyk said. “No cases are confirmed yet that are Maine-acquired.”
Another tick-borne disease that Maine residents should be aware of is ehrlichiosis, a bacterial infection that can cause life-threatening breathing difficulty and bleeding disorders and can be transmitted by the lone star tick and blacklegged tick. This disease is difficult to positively diagnose because it’s so similar to anaplasma, but in Maine, the number of probable cases has been climbing in the past few years. In 2018, there were nine probable cases of ehrlichiosis in Maine; and in 2019, there have been 19 probable cases.
Awareness is key
In recent years people’s awareness about ticks and the many diseases they can carry has increased dramatically in Maine, and tick researchers are hoping that will make a difference moving forward.
May is Lyme Disease Awareness Month in Maine, and the Maine Department of Health and Human Services is encouraging residents to be “tick aware and tick alert” when spending time outdoors, especially as the weather warms and becomes more favorable for both ticks and people.
Lyme disease and other tick-borne diseases are treatable and most individuals recover completely with proper treatment; however, the easiest way to avoid these diseases is to be vigilant about protecting yourself from ticks.
“We want people to be aware of ticks, but we don’t want them to be afraid of ticks,” Dill said. “We want people to go outside and do all the things Maine has to offer. Just take those precautions, whether it’s using repellents or covering up — and do tick checks.”
To learn about how to protect yourself from ticks and to learn how to send ticks in for free identification, visit the UMaine Tick Identification Lab website at extension.umaine.edu/ticks.
Related: Ticks on migratory birds