Connecticut Releases 2024 Tick Surveillance Data, Finds Rising Risk

CONNECTICUT — The Connecticut Agricultural Experiment Station has published its 2024 report on tick activity, showing a growing presence of disease-carrying ticks and an expanded range of newer species across the state.

The report marks the fifth year of statewide tick tracking by the Center for Vector Biology and Zoonotic Diseases. More than 4,000 ticks were collected from 40 public sites in all eight Connecticut counties during the spring, summer, and fall months. Researchers tested the ticks for five pathogens that can cause illness in people: the bacteria linked to Lyme disease, anaplasmosis, babesiosis, hard tick relapsing fever, and the Powassan virus.

Blacklegged ticks, often called deer ticks, made up the majority of those collected, with 3,503 samples. Longhorned ticks were the second most common, with 696 found. The rest included 74 American dog ticks and 72 lone star ticks.

Lone star ticks and longhorned ticks were found in four counties — Fairfield, New London, Middlesex, and New Haven. When the survey began in 2019, these species were only found in Fairfield and New London.

New London County had the highest number of adult blacklegged ticks, averaging 83 per acre, and the highest count of younger ticks (called nymphs), at 25 per acre. Litchfield County had the highest infection rate among adult female ticks at 65 percent. Fairfield County had the highest rate in nymphs at 41 percent.

The statewide infection rates in blacklegged ticks were as follows:

• Lyme disease: 54 percent in adults, 23 percent in nymphs
• Babesiosis: 16 percent in both adults and nymphs
• Anaplasmosis: 7 percent in adults, 2 percent in nymphs
• Hard tick relapsing fever: 3 percent in adults, 2 percent in nymphs
• Powassan virus: Found in less than 1 percent of adult ticks, not found in nymphs

“The spread of lone star and longhorned ticks in Connecticut, along with rising blacklegged tick numbers, shows why ongoing tick monitoring matters,” said Dr. Megan Linske, a tick researcher at the station. “People should take simple steps to protect themselves when outdoors.”

Health officials advise residents to stay on trails, avoid thick brush, wear long and light-colored clothing, tuck pants into socks, and consider clothing treated with tick repellent. Regular tick checks after spending time outside can also help prevent illness.