The Connecticut Agricultural Experiment Station released on March 23 the findings from its sixth year of statewide active tick surveillance, providing updated information on tick populations and disease prevalence across Connecticut.
The annual survey is important for public health, as it helps track the presence of ticks and the pathogens they carry. This information supports efforts to reduce tick-borne illnesses in the state.
Researchers collected more than 10,000 ticks from 40 publicly accessible locations in all eight counties during spring, summer, and fall of 2025. The study focused on five human disease-causing pathogens: Anaplasma phagocytophilum (anaplasmosis), Babesia microti (babesiosis), Borrelia burgdorferi (Lyme disease), Borrelia miyamotoi (hard tick relapsing fever), and Powassan virus. Blacklegged ticks remained consistently abundant throughout sampling efforts. While higher numbers of longhorned and lone star ticks were observed this year, researchers said these totals were largely due to isolated sampling events with large clusters at individual sites rather than widespread increases.
New London County had the highest average adult blacklegged tick density at 81 per acre, while Litchfield County reported the highest nymphal density at 28 per acre. Pathogen testing showed that Lyme disease infection rates were highest in adult female ticks from Fairfield County (68%) and in nymphs from New Haven County (32%). Statewide infection rates for blacklegged ticks included Borrelia burgdorferi at 55% in adults and 25% in nymphs; Babesia microti at around 14% for adults and nymphs; Anaplasma phagocytophilum at up to 9% in adults; Borrelia miyamotoi at about 2%; and Powassan virus detected rarely.
“Ticks are still a common part of the Connecticut landscape, including both established and emerging species,” said Dr. Megan Linske, Vector Ecologist specializing in Tick-Host-Habitat Dynamics at CAES. “People can come into contact with ticks in their own yards or while enjoying the outdoors, so taking preventative measures is key to lowering the risk of tick-borne illness.” Linske encouraged residents to conduct routine tick checks after outdoor activities, wear protective clothing such as long sleeves or permethrin-treated garments, tuck pant legs into socks when necessary, and stay informed about local risks through resources provided by CAES.
The Connecticut Agricultural Experiment Station receives support from its Research Foundation, a nonprofit organization according to the official website. It was also noted as being the first agricultural experiment station established in the United States according to its official website.
CAES maintains its main campus in New Haven according to its official website, where it focuses on research and education aimed at resolving agricultural, public health, and environmental challenges according to its official website. The station operates under an eight-member Board of Control authorized by state law according to its official website. As a pioneering research organization nationwide according to its official website, CAES offers services such as soil testing and community programs designed to improve resident well-being throughout Connecticut while partnering with various institutions.
