N.H., Vt. tick population likely steady or higher this season, experts say

Valley News Staff Writer
Published: 4/23/2019 10:31:35 PM

After years of mild winters helping tick numbers soar in the warmer months, the hefty snowfall this past season is unlikely to put much of a dent in the region’s parasite population, according to experts in Vermont and New Hampshire.

“It takes a lot to kill them over the winter,” said Eliza Doncaster, vector management coordinator for the Vermont Agency of Agriculture. “To really have a big die-off, it would need to be way below zero for a long time with no snow.”

Rachel Maccini, an entomologist and program coordinator for the University of New Hampshire Cooperative Extension, agreed, saying the tick season is expected to be at least the same or even higher than last year, due to a wet fall and spring.

Generally, moisture keeps ticks alive and prevents them from desiccation — death from drying out. Then, the snow cover during the winter gives the ticks insulation from the freezing cold.

The bloodsucking arachnids come in three forms — larval, nymph and adult. The larval ticks, freshly hatched from their eggs, are most active during the summer and cannot transmit Lyme disease.

But soon after their first “blood meal” and molting, nymphal ticks cause the most cases of Lyme disease due to their small size in the late spring to early summer, according to Doncaster. Then the adults, which are most active in the spring and fall, go after a large animal like a human or dear, to get enough food to produce eggs.

In total, tick season extends from late April or early May to October or November, depending on the weather. Doncaster and Maccini both say some areas in Vermont and New Hampshire already have seen tick activity.

While there have been studies of tick populations in Connecticut and New York, Vermont is just beginning to track the numbers, according to Doncaster.

“Everyone says it’s getting a little worse and worse each year, but we don’t have data going back far enough to make a conclusion,” she said. Last year, the department started a new study with the Vermont Department of Health studying the tick population at 40 sites four times a year. In the 2015, the department started another study with the goal of visiting every town in Vermont and assembling a small dataset for each place.

Meanwhile, Maccini will be doing her first “tick drag” in a camp location to identify local hot spots. The sampling technique consists of taking a piece of corduroy cloth, dragging it through grassy and wooded areas and then counting the number of ticks that latch onto the cloth.

And while researchers in the Twin States are busy nailing down data, hikers and outdoorspeople have much more practical — if familiar — tasks on their to-do lists.

“Wear your insect repellent and do tick checks,” Doncaster said. “I can never say that enough.”

Amanda Zhou can be reached at azhou@vnews.com.

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