DARIEN — Every year, as the air warms and the ground thaws, blacklegged (deer) ticks emerge in abundance throughout the Northeast and bring with them the threat of Lyme disease.

But with an unusually warm winter, and a tick season that never really ended, some suburbanites are wondering if that will mean more ticks this summer, and more instances of Lyme.

Fordham University’s Louis Calder Biological Field Station in Armonk, N.Y., studies ticks extensively. Dr. Tom Daniels, director of the station, said predicting the tick season at this point in the region is complicated. But he suspects the warm weather actually works against some ticks.

“Because of the relatively warm weather we’ve had, there has been some tick activity already,” Daniels said. “If you’re not expecting ticks this time of year, it’s possible that you would be bitten by an adult female,” which have a higher infection rate than adult males. “But it’s not very common, because adults are not very common.”

Adult ticks are primarily active in cooler weather and, because of their size, are more easily spotted. But the primary vector of Lyme is ticks in their nymphal stage, of which 25 to 30 percent carry the Lyme bacterium. These smaller ticks are more active in warmer months, typically peaking from late May to early June and persisting through the fall.

Daniels hypothesized that mid- to late-season nymphal activity may be negatively affected by the warm weather.

More Information

The Calder Center’s Tick Index, which assesses the weekly risk of being bitten by a nymphal or adult deer tick, can be viewed at http://www.fordham.edu/info/21491/indices/3038/fordham_tick_index beginning in the spring.

For tips on avoiding bites and staying Lyme-free, visit darienct.gov/health.

As evidence, Daniels cited the spring of 2013, following the particularly warm winter of 2012-13, in which very few ticks were found by Daniels and his team at the Calder Center. “The evidence suggests that the tick population took a hit because they didn’t have cold temperatures,” Daniels said.

Daniels also suggested that the absence of significant snowfall — which acts as an insulation for ticks in the cold and can keep them from drying out — could also have taken its toll on tick populations.

But whether or not that will be the case is difficult to judge. At present, local officials are still dealing with last year’s tick season that never really ended.

Darien Director of Health David Knauf said people can bring ticks to one of two state Agricultural Experiment Stations in town year-round to have them tested for Lyme.

“Usually during the course of the winter there’s a month or two or three when the ground is snow-covered and frozen and we don’t have ticks,” Knauf said. “We didn’t have that this year. They were out and about all winter.”

Daniels said that’s not such a bad thing.

“We think if they’re more active, they’re more likely to burn out,” he said. “They’ll lose energy and we won’t see them later in the season.”

“Tick season could be extended in the sense that it might start earlier. But that might be offset by that fact that it was particularly warm, which could shorten the season,” Daniels said.

Still, Daniels stressed, there are many variables at play and much uncertainty regarding the intensity of 2016’s tick season.

justin.papp@scni.com; dariennewsonline.com