Will a mild winter impact ticks?
In Connecticut, spring brings with it warm weather and budding flowers. But it’s also the time when residents break out their flea collars for Fido and Figaro, and become more aware of the pesky ticks their pets could be harboring.
Ticks are not only a bloodsucking nuisance for dogs and cats, but black-legged ticks, also known as deer ticks, are carriers of Lyme disease, which is caused by bacteria and transmitted to humans through the bite of infected ticks.
Lyme disease is the most prominent tick-associated disease of concern in Connecticut with 2,022 cases reported in 2017, according to a report by the Connecticut Department of Health. In that report, Wilton had 14 confirmed cases.
Lyme disease symptoms vary from victim to victim, and are typically marked by a rash, headache, fever, and chills, and later by possible arthritis and neurological and cardiac disorders.
So, with this past winter being a mild one, will this be a good year or bad year for ticks?
The answer is complicated and depends on a number of factors.
Connecticut’s tick population is affected by both climate change and temperature change, according to Dr. Goudarz Molaei, research scientist and director of passive tick surveillance and testing at the Connecticut Agricultural Experiment Station (CAES).
“We’ve had a relatively mild winter but we also had some periods of bitterly cold weeks as well. But we also did not have much snow coverage and that is important for ticks and rodents,” Dr. Molaei told The Bulletin.
In years when there is ample snow coverage, the snow provides shelter and insulation for both rodents and ticks and they do well in the winter, he said.
“This winter has seen relatively cold temperatures but not much snow on the ground. So we’ve been seeing a substantial decrease in the number of ticks from Dec. 1, 2018 up to today,” he said.
While the number of ticks is lower so far compared to the previous winter, it’s too early to celebrate because ticks have a two-year life cycle. “The number of ticks from the preceding year also impacts tick density,” Dr. Molaei said.
Another impact on tick density is the population of deer (as reproductive hosts for ticks) and rodents (as reservoir hosts that provide disease agents to ticks).
White-footed mice are a popular rodent host for black-legged ticks, so when the white-footed mice population is high, tick population is likely to be higher too.
Rodent population is affected by acorn yield, according to Dr. Molaei. In years when there are a greater number of acorns on the ground, he said, there are higher masses of rodents.
Acorn population has been especially bountiful the past few years in Connecticut, as evidenced by a growing squirrel population which, like mice, thrive when the nut is plentiful.
Taking all those variable factors into account, the CAES has initiated a new statewide active tick surveillance program that will provide information on the distribution and abundance of ticks.
Ticks will be collected at 40 sites across all eight counties in Connecticut from April through October with a focus on the black-legged tick.
The study will also note the prevalence of current and newly emerging agents of human disease including: Borrelia burgdorferi, the agent of Lyme disease, Babesia microti (babesiosis), Anaplasma phagocytophilum (anaplasmosis), B. miyamotoi (a relapsing fever Borrelia), B. mayoni (a new Lyme Borrelia), and Powassan virus.
In an effort to provide more information on ticks and Lyme disease, Dr. Molaei and a panel of professionals are holding a community conversation about mosquito and tick-borne diseases on Tuesday, May 21, from 7 to 9 p.m. at the Darien Library, 1441 Post Road, Darien.
The panel will discuss how the CAES examines ticks, how it evaluates methods to control ticks, and how tick-borne diseases are diagnosed and treated.