Esh Schaden knows the Bird Hills Recreation Area like the back of his hand. During one of his off-trail runs this April, he stumbled through several bushes and, as a result, got some scratches on his legs. In his house after the run, he examined the scratches and discovered something that had not been there before: a small parasite known as a tick.
Upon closer inspection, he found four more. He quickly brushed them off before they could do any damage.
“I guess I was running through bushes, but it’s really nasty because they try to get to pockets and places where you won’t find them,” Schaden said. “It’s really nasty and, you know, I don’t appreciate that.”
For Schaden, the most alarming part of the story was not just the amount of ticks he had found, but also the time and place in which they had appeared.
“I was shocked to just end up with that many ticks on me this early in the year,” Schaden said. “It’s warm, but I feel like in April, I usually don’t find this many ticks on me, especially here.”
Schaden’s story is a scenario that increasingly more people need to be wary of. As climate change alters the seasons and regions in which different species thrive, the pests we previously perceived as small hindrances are becoming serious threats.
A study done by the CDC showed a major increase in Lyme disease cases from the 1990s to 2022. The nationwide study measured the average number of Lyme disease cases per 100,000 people. At the beginning of the study, there were an average of 3.86 cases per 100,000; in 2022, the number of cases increased to 18.77. With these numbers, it is hard to determine if there is a trend in the data, considering the fact that increasing diagnosis of a disease doesn’t always mean an increase in the disease itself.
But other data from the National Institute of Health also suggests that the ranges in which ticks can live are expanding. As temperatures rise, ticks are able to travel to higher latitudes that were previously inaccessible. These locations, previously safe from certain tick populations and the diseases they carry, are now face-to-face with them. For example, in Canada, four tick-borne diseases—Anaplasmosis, Babesiosis, Powassan virus, and Borrelia miyamotoi disease—have emerged and now pose a threat to citizens.
Another implication of climate change for ticks is that more of them can survive warmer winters, increasing their populations in the following years. Although ticks are very resilient when it comes to the cold—being able to survive in temperatures as low as -7.06 degrees Fahrenheit—they don’t usually search for a host below temperatures of 40 degrees Fahrenheit. Warmer temperatures cause the seasons when ticks are searching for a host to begin sooner and end later, exposing the world to ticks for a longer period.
However, the trend of migrating to colder climates is not unique to ticks. An article from the University of Southern California estimates that 50% of the planet’s 4,000 species, from frogs to bears to great white sharks, are moving to higher latitudes. This leads to different human-animal interactions. So, as the climate continues to change, our behavior will need to as well.
