As ticks gain ground in Alaska, researchers say health risk remains low for now

Over the last few years, a team of researchers in Alaska has been testing ticks found around the state to see what kind of threat the tiny bloodsuckers pose to humans, pets and wildlife.

So far, the team has found no evidence that the small arachnids currently lurking in the woods and grasses around Alaska carry the pathogens that cause Lyme disease, tularemia or other human diseases, according to a comprehensive report slated to be published by the state’s health department that summarizes more than a decade of tick research in Alaska.

Out of dozens of ticks found in Alaska and tested over a two-year period to see whether they carried any pathogens, just one was found to be carrying Lyme disease — and it came off a dog that had just traveled from New York, said Micah Hahn, an associate professor of environmental health at the University of Alaska Anchorage who helped author the report.

Hahn said the findings showed that right now, the threat ticks in Alaska pose to humans and domestic pets appears to be relatively low. But that could change, and researchers continue to worry about the possibility of ticks that are carrying Lyme and other diseases hitching a ride on pets arriving in the state from Outside, and infecting wildlife here.

“The worry is that a tick that is infected will get imported to the state on a pet, and then fall off in the woods when the dog is walking through Kincaid or through Far North Bicentennial, and then bite a squirrel or vole or another wild animal that’s living in that area. And then all of a sudden, we have this pathogen introduced into the state,” Hahn said.

For Lyme disease to become a serious problem in Alaska, Hahn said it would take multiple instances of infected ticks falling off into the environment and biting wildlife.

The likelihood of more ticks and tick-borne diseases becoming established in Alaska has increased as winter temperatures have become milder in recent years, creating a climate more hospitable to ticks, Hahn said. Southcentral and Southeast Alaska are “pretty hospitable (to ticks) now, and these areas of hospitability will expand with climate change,” she said.

For many years, Alaska has been home to tick species that infect rabbits, voles, mice, squirrels and birds, but are not known to pose any threat to humans. In the last decade, 10 non-native tick species have been identified in the state, including the Lone Star tick and the American dog tick. Many of these non-native species can be carriers for Lyme and other diseases.

Ticks regularly travel to Alaska from the Lower 48 by hitching a ride on humans and pets. As these ticks have gradually become more established here, researchers have been trying to determine the risks that non-native ticks posed to people, pets and wildlife.

Hahn and others have conducted passive surveillance of ticks found around the state as part of the Alaska Submit-A-Tick Program, an ongoing project where residents can ship ticks to the state’s public health lab for identification and testing.

Scientists also visited nine recreation sites in Anchorage, Soldotna, Homer, Kenai and Anchor Point in the summers of 2019 and 2020 to see what ticks they could find there, and trapped small mammals in the area to test them for tick-borne illnesses.

As part of those efforts, a total of more than 2,000 ticks were tracked in Alaska between 2010 and 2022. About half were found on domestic animals, and most were discovered during the summer months. The vast majority were native tick species. Of the non-native ticks reported, about half were collected from humans or pets that had traveled outside of the state within the last two weeks.

Those numbers represent just a small percentage of the total number of ticks in Alaska during that time, Hahn said. At least another decade of research is needed to determine whether the number of ticks in Alaska is actually increasing, she said.

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From a wildlife health perspective, a major concern is the winter moose tick, a species of tick that has been found on moose, elk and deer in the Lower 48, Western Canada and the Yukon, said Kimberlee Beckmen, a wildlife veterinarian with the Alaska Department of Fish and Game.

The winter tick poses a serious health issue that can kill moose during the winter months, especially calves and yearlings. The ticks cause the moose to itch and scratch off significant amounts of hair and cause substantial blood loss, which leaves the moose vulnerable to the cold.

So far, there have been no detections of the winter tick in Alaska, but Beckmen said she’s “very concerned” that it could make its way to the state soon given recent detections in the Whitehorse area.

The state is planning a winter tick surveillance project over the next five years, and Beckmen said she encouraged the public to report sightings of moose with hair loss.

Hahn said it was important for Alaskans to know what ticks look like so they can identify them on animals and people; to check themselves and their pets for ticks after spending time outdoors in grassy or wooded areas; to check wildlife for ticks while trapping or hunting; and to talk to their veterinarians about flea and tick prevention if they plan on traveling with their pets to parts of the Lower 48 where ticks that carry diseases are more common.

Adult ticks are very small, about the size of an apple seed, she said. When they feed, they swell with blood, becoming as large as a grape and sometimes harder to recognize.

“Alaskans should be aware of ticks, particularly when they’re traveling, for their own protection, and to make sure that they don’t bring ticks back with them so that they becomes a problem locally in the state,” she said.

Hahn said the recent research also highlighted a need for clinicians and veterinarians in Alaska to familiarize themselves with the symptoms of common tick-borne diseases and learn about the travel history of patients exhibiting symptoms. She said a lot of tick outreach by the state is focused on these groups in particular.

“We found that there was a lot of room for education around ticks among pet owners and vet clinics,” she said. “They really are probably the most likely to come in contact with ticks in the state.”