Last winter’s warmer temperatures allowed more ticks to survive into spring. In addition, an earlier spring is lengthening tick season. Experts say this trend will continue as the climate warms.
“This is the first winter where I've still seen live ticks on patients every month throughout the winter,” said Randy Hays, who has been a veterinarian in Durango, Colorado, for 20 years.
Hays says that for the past five to six years, he’s seen a steady increase in tick activity. He says it’s not only people and their pets that are experiencing more ticks, but wildlife as well. He says it’s all connected in the wildland-urban interface.
“And so our town deer definitely have ticks,” Hays said.
Hays referred to a client he saw earlier this year who lives downtown, who had so many ticks in their home that they had to call pest control.
“She's got a little small dog that just hangs out in its backyard,” he said. “But there's deer that bed down at night in the front yard.”
And if those deer have ticks, the ticks jump off and look for their next host.
“They hang out in the grass or nearby bushes, and then they'll crawl up a blade or onto a leaf, and they'll just hang out waiting for another four-legged-furry-animal to come by and pick them up, so they can continue their lifecycle,” Hays said.
There are over 20 different species of ticks in Colorado. Most of them are known as three-host ticks. This means they feed on three different hosts during their life cycle.
“A young tick is going to wait for a small mammal, maybe a mouse, or a rabbit,” said Lisa Mason, the Horticulture Specialist and Entomologist at the CSU extension office in Durango.
“And it waits. When that mammal walks by, the tick jumps on the mammal, and then it will feed. And then it will drop.”
She said the tick will do this two more times.
“That third host, that third part of the life cycle is when that impacts humans the most,” Mason said.
Mason says it’s hard to surveil tick populations beyond anecdotal evidence. But currently there’s a citizen science program in Colorado for tick monitoring.
“Through this program I receive around 300 ticks every year from around the state,” said Chris Roundy, public health entomologist with the Colorado Department of Public Health and Environment in Denver. “It's given us a really good idea of where people are encountering ticks, what types of ticks they're finding.”
There’s a portal on the CDPHE website where people can submit photos and even send ticks they’ve found to an entomology lab.
“The ticks that are sent in, we know were found on a host,” Roundy said. “That gives us a good picture of what ticks are out there that humans or their pets are encountering. This lets us cast a very wide net around the state.”
Roundy says that while it’s hard to draw clear evidence from this data, this summer has been particularly bad for ticks in Colorado.
“A wet 2023 meant a lot of tick babies,” Roundy said. “That population of ticks is one that we're still dealing with. And then our warm spring, our mild winter, meant that they got an early start.”
He added that 90% of the ticks people send in are the Rocky Mountain Deer Tick and American Dog Tick. Roundy also leads another tick surveillance program with local health departments across the state where they actually go looking for the ticks
“It's called tick dragging because we take a white cloth and drag it through the grass and brush where we expect to find ticks,” Roundy said. “The ticks think that they found a nice host to take a blood meal from. So they grab onto that cloth.”
The white cloth makes it easy to identify the ticks. Roundy’s team then sends them to the CDC for pathogen testing.
While the ticks in Colorado don’t carry Lyme Disease, they do carry Rocky Mountain Spotted Fever and Colorado Tick Fever, says veterinarian Randy Hays.
“And so not only are people seeing more ticks on themselves or their pets or their livestock, but they're also experiencing more tick-borne disease among humans,” Roundy said. “Doctors are seeing that; human physicians are as well.”
Hays, Roundy and other experts say it’s important to stay safe. Wear long pants and avoid tall grass. And if you find a tick on you or your pet, remove it with tweezers as close to the skin as possible.
To learn more about the symptoms of tick-borne diseases, how to stay safe, and how to participate in the citizen science monitoring program, visit cdphe.colorado.gov.