HELENA, MT – The Montana Department of Public Health and Human Services (DPHHS) has confirmed the presence of blacklegged ticks—commonly known as deer ticks—for the first time in Montana, with recent findings in Dawson and Sheridan counties.
According to DPHHS, three blacklegged ticks (Ixodes scapularis) were discovered through surveillance efforts over the past year. One was confirmed in Dawson County by Rocky Mountain Laboratories in 2024, and two others were confirmed in Sheridan County later that year by the Centers for Disease Control and Prevention (CDC). While these ticks tested negative for human disease-causing pathogens, including Lyme disease, their presence is prompting increased monitoring.
Devon Cozart, Vectorborne Disease Epidemiologist with DPHHS, emphasized the significance of the findings. “The presence of this new type of tick in the state could mean that Montanans have an increased risk of exposure to diseases that weren’t previously a threat in Montana,” Cozart said.
Blacklegged ticks are known carriers of several illnesses such as Lyme disease, anaplasmosis, babesiosis, and Powassan virus, though there is currently no evidence of increased disease risk in Montana. These ticks are typically smaller and darker than other common Montana species, including the Rocky Mountain wood tick and the American dog tick.
DPHHS is launching a citizen scientist initiative to support ongoing tick surveillance. Residents, particularly in Dawson and Sheridan counties, are encouraged to report suspected blacklegged tick encounters via an online form available through the department’s website. Instructions are also provided for submitting ticks for identification.
To prevent tick bites, DPHHS advises using EPA-registered repellents, treating gear with permethrin, checking for ticks frequently, and removing ticks promptly. Individuals are also encouraged to consult a healthcare provider if symptoms like fever, rash, or headaches occur after a tick bite.
Further investigation is underway to determine whether the blacklegged tick is establishing a permanent habitat in Montana.
For more information about ticks and tickborne diseases, please visit: About Ticks and Tickborne Disease | Ticks | CDC.
