Is This Going to be a Bad Tick Year?
Written by NEWVEC Executive Director, Dr. Stephen Rich
Every spring I am asked to prognosticate on the coming seasonal abundance of ticks in New England. I know I’m not alone. Everyone whose name is associated with tick research probably hears the same question. And I know that some of my colleagues do hold forth a projection, but I have seldom heard anyone report a favorable reckoning. That might be because, like weather reporting, there’s very little downside to overreporting and much grinding and gnashing of teeth when reality exceeds prediction. It's always safer to predict a storm that doesn’t come than to fail to warn about a tempest.
The internet is packed with divinations about how the preceding winter will affect the preponderance of ticks come spring and, like all things interwebbed, there are many opposing viewpoints. Some speculate that a harsh winter will kill ticks and thus reduce their numbers in the following seasons. Others cite studies that show heavy snowfall actually provides an insulating blanket to protect ticks from the cold. Could it be that there is truth in these seemingly diametrically opposed viewpoints?
Having gone into the woods to collect ticks (even though they are hoping to collect me) for decades now, I am always reluctant to chime in on the acarological prophesying. My general message is that every spring in New England is tick season and whether this year is slightly better or slightly worse ends up mattering very little. What has changed from year to year is the geographical range of ticks. When I was student at the Harvard School of Public Health in the early 90s, it was quite rare to see blacklegged ticks any distance off the coast. Inland communities at that time had very few ticks. All that changed in the late 1990s and into the new century. In 2025 ticks can be found in virtually every county of every state in the northeast US, and they’ve even become abundant in our neighbors to the north (Ontario, Quebec, and the maritime provinces).
Beyond that, where ticks were found last year, they will be found this year. The variance that one might detect, or perceive, is most generally attributed to either very localized distribution (tick densities are patchy) or misinterpretation of temporal patterns. What does that mean? The difference in tick counts between the right side and the left side of any given trail in tick habitat is likely to be as great if not greater than the count for that same trail in the prior year. Moreover, since people often forget the tick activity life cycle—April/May adults followed by June/July nymphs, and ending the year with October/November adults—and erroneously compare different periods between successive years. For many years I would see family friends at the start of the youth hockey season in New England (generally at the end of August), and they would invariably tell me it’s been a “great year for ticks,” meaning that they weren’t seeing many. Then I have to remind them that there are never many active ticks in New England in August/September. They were tricking themselves into an observation by comparing that August/September with a prior year’s May/June, the time of year when deer ticks are consistently plentiful.
Why would people ask for tick predictions? I assume it’s with the hopeful expectation that eventually the growing trend of ticks and tick-borne diseases will reverse or at least subside. Recently, we estimated that at least 1.36 million people are bitten each year, and there is presently no reason to suspect that number is likely to decrease. So my message is consistent: use personal protection (including permethrin treated clothing and repellents containing DEET or picaridin) and conduct daily tick checks when outdoors. While tick densities are not likely to decrease, there are practical steps that people can take to prevent tick-borne diseases!
