Exploring the rise in tick populations

In this interview with dvm360, Susan E. Little, DVM, PhD, DACVM, Krull-Ewing professor of parasitology at the Center for Veterinary Health Sciences at Oklahoma State University in Stillwater, talks about her lecture It’s Always Tick Season, presented at the 2025 Veterinary Meeting & Expo (VMX). Little discusses the boom in tick populations over the last decades, as well its driving factors and the risk of tick-borne diseases in pets.

Below is a partial transcript which has been lightly edited for clarity.

Susan E. Little, DVM, PhD, DACVM: The increase we've seen in tick populations in the last few decades has just been incredible. I mean, I think it was beyond what anybody's estimations were in terms of what the tick explosion was going to look like, and so we've got more ticks, more places. They've moved up in latitude, up in altitude. The geographic spread has just been phenomenal, and there's a number of reasons for that. We've certainly seen habitat change and increased wildlife host populations, right? So that leads to increased ticks and ticks [in] more places.

We've seen introduction and establishment of new species, and so those have taken off because they found a welcoming environment with the habitat and the host there to feed them. And then we're also dealing with the effects of climate change, and so we've got earlier springs, later falls, milder winters. I know it doesn't feel like it right now, but on average, our winters are much milder than they've been historically. And so with that increased temperature, the ticks have really taken advantage of that. It gives them more degree days to be out there, finding a host, feeding on a host, and if they find a dog or a cat that's not protected with tick control, they're going to take advantage of that.