According to researchers, the epicenter of Maine’s tick problem is the Midcoast region. Over six years of operation, the University of Maine Cooperative Extension tick lab has tested more than 22,000 ticks from various locations throughout the state. Their findings reveal that ticks from Hancock, Knox, Lincoln, and Waldo counties are most likely to carry pathogens responsible for Lyme disease, anaplasmosis, and babesiosis—the three most prevalent tick-borne illnesses in Maine.
The Midcoast region not only has the highest reported human cases of these illnesses but also the most hospitalizations related to them. “We don’t have a definitive answer as to why the Midcoast has become Maine’s tick hotspot,” stated Griffin Dill, coordinator of UMaine Extension’s tick lab. “The area shares similarities with southern Maine, including climate, the presence of animal hosts, and suitable habitat. We are still investigating the underlying reasons.”
Similar to southern Maine, the Midcoast boasts diverse habitats, abundant wildlife species, and increasingly mild winters, all of which favor tick survival and the transmission of pathogens. Dill noted that limited on-the-ground tick surveys suggest that tick abundance in Midcoast Maine is not significantly higher than in southern Maine.
Scientists like Susan Elias, a staff scientist at the Maine Medical Center Research Institute's vector-borne disease laboratory, are exploring how human behavior may differentiate the outcomes of tick populations in Midcoast Maine from those in southern Maine. While age and lifestyle differences at the county level could provide some explanations, their analysis of town-level pathogen and illness data indicates that residents living in prime tick habitats in both regions tend to be older and lead active lives.
The research conducted by Elias and her colleague Robert Smith concluded that existing data for Maine lacks specificity to accurately determine the contributions of various factors affecting tick-borne illness risks. They emphasized that differences in human behavior within residential landscapes are plausible and warrant further investigation.
Recent studies published in the latest edition of the Journal of Maine Medical Center reveal that the Midcoast tick cluster has been present for 15 years. However, researchers had previously overlooked it because they were comparing total counts of positive ticks and human cases reported by county rather than analyzing the rate of infected ticks and cases per capita. Dill explained that focusing on infection and illness rates per 100,000 residents helped identify the Midcoast cluster.
Ticks sent in from residents of Lincoln County showed the highest rate of the bacteria causing Lyme disease, Maine’s most frequently reported tick-borne illness, with 52% of adult deer ticks testing positive. The average positivity rate across all counties was 44%. Additionally, the Midcoast counties report some of the highest human rates of Lyme disease, anaplasmosis, and babesiosis in the state, indicating that ticks in Hancock, Knox, Lincoln, and Waldo counties are effectively transmitting pathogens to humans.
The prevalence of tick-borne diseases poses an increasing public health risk in Maine, especially as ticks expand their range, likely due to climate change. In 2024, Maine reported a record 3,218 cases of Lyme disease, surpassing the previous year's total of 2,943 cases, according to statistics from the Maine Center for Disease Control and Prevention (CDC).
Symptoms of Lyme disease include a characteristic bull’s-eye rash (though not everyone exhibits this symptom), fever, headache, joint pain, and fatigue. When detected early, Lyme disease is treatable with antibiotics. Anaplasmosis and babesiosis, while less common, present similar symptoms but typically do not cause rashes. However, both can lead to severe complications, including respiratory failure, renal failure, and hemorrhage.
The Maine CDC provides year-round public education on how to prevent tick bites. Megan Porter, a CDC veterinarian and public health educator specializing in vector-borne diseases, announced that the agency will launch a targeted social media campaign aimed at residents and visitors in tick hotspots, including southern and Midcoast Maine, as well as some Downeast coastal areas experiencing rising cases.
Warmer, shorter winters are contributing to increasing tick populations. Dill noted that even the snowy winter of 2024-25 likely did not significantly reduce tick populations, as snowpack insulates against extreme cold temperatures that typically kill ticks. Furthermore, climate change has led to earlier tick emergence in spring and extended activity into fall, with ticks actively seeking hosts whenever temperatures exceed approximately 39 degrees Fahrenheit.
Maine is home to 15 tick species, but the blacklegged tick, or deer tick, is primarily responsible for most of the state’s tick-borne diseases, according to the tick lab’s latest annual report. Invasive species, such as the Lone Star tick, also pose threats to human, wildlife, and domestic animal health.
To address these public health threats, UMaine Extension engages in “passive surveillance,” which involves studying ticks submitted by the public to monitor Maine’s growing tick population and their associated pathogens. A significant portion of the ticks submitted were found on individuals after engaging in outdoor activities like yard work, gardening, or playing in their own backyards.
The tick lab has established long-term monitoring sites across Maine, including locations in Wells, Orono, and Bar Harbor, to study the impact of soil temperature, moisture, air humidity, and wildlife trends on tick density and pathogen transmission. These stations will also monitor for other disease-carrying tick species that have yet to establish themselves in Maine but have migrated to other parts of the U.S., such as the Lone Star tick and the Asian longhorned tick.
Residents who wish to submit ticks for identification and pathogen testing can complete the online submission form available on the tick lab’s website at ticks.umaine.edu and mail their samples to the Tick Lab at 17 Godfrey Drive, Orono, ME 04473. Identification is free, while pathogen testing incurs a fee of $20.
To minimize the risk of tick bites, especially in gardens and wooded areas, Porter recommends wearing light-colored clothing that covers arms and legs, tucking pants into socks, using an Environmental Protection Agency-approved tick repellent, and performing thorough tick checks after outdoor activities. For those who have been in tick-prone habitats, drying clothes on high heat for 10-15 minutes before washing is also advisable.
