Maine Tickborne Illness Cases Surge as Lyme Disease Reports Climb 32 Percent in One Year

AUGUSTA, Maine – Tickborne illnesses are rising sharply across Maine and much of the United States, with state health officials reporting record numbers of Lyme disease, anaplasmosis and babesiosis cases as residents face increasing exposure close to home.

The Maine Center for Disease Control and Prevention reported 4,257 cases of Lyme disease in 2025, up from 3,218 cases in 2024. The increase represents a jump of more than 1,000 reported cases, or approximately 32 percent, in a single year.

Other tickborne illnesses also reached record levels in Maine last year. Reported cases of anaplasmosis rose from 1,284 in 2024 to 1,604 in 2025, an increase of nearly 25 percent. Babesiosis cases increased from 309 to 352, a rise of nearly 14 percent.

The numbers continue a troubling trend in Maine. Reported Lyme disease cases increased from 2,943 in 2023 to 3,218 in 2024 before climbing to 4,257 in 2025. Over that two-year period, Maine saw an approximately 45 percent increase in reported Lyme disease cases.

The threat has continued into 2026. As of May 19, the Maine CDC had already recorded 832 combined reports of Lyme disease, anaplasmosis and babesiosis for the year.

Maine’s growing tick problem is also reflected in data from the University of Maine Cooperative Extension Tick Lab.

In 2025, Mainers submitted 5,486 ticks to the laboratory from all 16 counties and 411 towns. That was an increase from 4,776 ticks submitted in 2024. Of the ticks submitted last year, 4,035 were blacklegged ticks, also known as deer ticks, the species primarily responsible for transmitting Maine’s leading tickborne illnesses.

Testing of adult and nymph blacklegged ticks submitted to the laboratory found that 41 percent carried the bacterium responsible for Lyme disease. Another 12.6 percent tested positive for the parasite associated with babesiosis, while 9.5 percent carried the bacterium responsible for anaplasmosis.

The Tick Lab also detected the bacterium associated with hard tick relapsing fever in 1.4 percent of tested blacklegged ticks and Powassan virus in 0.8 percent.

The laboratory’s findings show that tick exposure is no longer confined to hiking trails or remote wooded areas. Approximately 67 percent of people who submitted blacklegged ticks reported encountering them on their own property. Yardwork and gardening were the most commonly reported activities connected to those encounters.

Maine Pet Owners Also Face Growing Tick Threat

Maine’s expanding tick population is not only a threat to people. Dogs and cats that spend time outdoors may be exposed to ticks and can carry them back into homes, extending the risk to their owners and other family members.

The University of Maine Cooperative Extension Tick Lab warns that dogs and cats are commonly exposed to ticks during outdoor activity and are vulnerable to a number of tickborne diseases. Dogs may become infected with Lyme disease, ehrlichiosis and anaplasmosis. While cats do not typically exhibit symptoms of Lyme disease, they can contract other tickborne illnesses.

For Maine dog owners, the danger is particularly significant because Lyme disease is endemic in the state and blacklegged ticks remain Maine’s primary disease-carrying tick. The Maine CDC identifies the deer tick, also known as the blacklegged tick, as the primary vector in the state for Lyme disease, anaplasmosis, babesiosis, hard tick relapsing fever and Powassan virus.

The University of Maine Tick Lab recommends routine tick checks on pets, particularly after they have spent time outdoors, along with immediate removal of any ticks that are found. Pet owners are also urged to reduce tick habitat around their yards and speak with their veterinarian about tick preventatives and repellents appropriate for their animals.

Pet owners should also watch for changes in a dog or cat’s behavior or appetite after a suspected tick bite and contact a veterinarian if concerns arise, according to the Tick Lab. With a majority of reported blacklegged tick encounters in Maine occurring on residential property, family pets may face exposure during ordinary time spent in their own yards.

Maine is also seeing signs of additional tick species moving into the state. The Tick Lab reported receiving Maine’s first submitted Asian longhorned tick specimen in 2025, a nymph acquired in Cumberland County.

The laboratory also received 30 lone star ticks last year, including six identified as having been acquired in Maine without recent out-of-state travel. The lone star tick is not currently considered established in permanent populations in Maine, but it has been associated elsewhere with ehrlichiosis, Heartland virus disease and alpha-gal syndrome, an allergy to red meat and other mammalian products.

The deer tick remains Maine’s primary threat. State health officials consider Lyme disease, anaplasmosis, babesiosis, hard tick relapsing fever and Powassan virus endemic in Maine.

The rise in Maine mirrors a broader national trend.

In April, the federal Centers for Disease Control and Prevention reported that emergency room visits for tick bites were higher than normal in many parts of the country. Weekly emergency room visit rates were the highest recorded for that point in the season since tracking began in 2017 in every region of the United States except the South Central region.

The federal agency estimates that approximately 31 million Americans are bitten by ticks each year.

Lyme disease remains the most commonly reported tickborne illness in the country. The CDC reported more than 89,000 Lyme disease cases nationwide in 2023, while estimating that approximately 476,000 patients may be diagnosed and treated for the disease annually.

Health researchers have identified several contributing factors behind the spread of medically significant ticks, including warmer temperatures, longer active seasons, changing landscapes, expanding deer populations and increased human contact with tick habitat.

In Maine, deer ticks can remain active whenever temperatures are above freezing, giving residents additional opportunities to encounter them during portions of the fall and winter.

The state’s latest numbers show the growing risk is increasingly part of everyday life for Maine residents, with thousands of tick encounters occurring not deep in the wilderness, but in yards and gardens across the state, places where families and their pets spend time every day.