Ticks are emerging. Experts warn of rare but deadly vector-borne virus on the rise
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While the knowledge of ticks being vectors for Lyme disease is ubiquitous, there’s a lesser-known threat these insects carry that's concerning health experts: the Powassan virus.
The Metropolitan Mosquito Control District spotted its first tick of the season on March 27.
“We suspect they’ve been active for some time and have had numerous reports from members of the public that they've been found throughout the Twin Cities already,” the MMCD wrote online last month. Seasonal staff began to work on Monday.
Epidemiologist Elizabeth Schiffman, who supervises the Vectorborne Diseases Unit at the Minnesota Department of Health, joined MPR News host Cathy Wurzer on Morning Edition with information to prevent infection and keep people safe.
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What is Powassan?
It’s a tick-borne disease, but instead of being caused by a bacterium like Lyme, it’s viral.
The virus is found most commonly in blacklegged ticks — also known as deer ticks — and can be deadly to humans. There’s no vaccine or cure.
“We actually discovered the first case in Minnesota back in 2008, so it’s not brand new to us, but we’ve definitely seen an increase in cases over the last few years,” Schiffman said. “I would say it’s probably the most serious of our tick-borne diseases.”
Powassan hits older people and immunosuppressed individuals the hardest, she explained. It can lead to severe illness and death.
“And people who do survive, often will have some long-term impacts after the fact,” Schiffman added.
There were 14 confirmed cases of Powassan virus in Minnesota last year.
What are the symptoms?
Symptoms start to show within 1-4 weeks of being bitten by an infected tick and can include a fever, vomiting, headache and weakness.
“We think that there are probably some cases of Powassan that are just mild or maybe even asymptomatic, especially in younger people,” Schiffman said.
But for those who become very ill, severe headaches, neurological issues, seizures, meningitis and encephalitis can develop. While there’s no treatment for Powassan, those patients may be hospitalized and get respiratory support.
Should dog owners worry?
Ticks are a common concern for people with pets who spend time outdoors. Blacklegged ticks carry the most disease affecting humans, including Lyme, which also sickens dogs. MDH reports Minnesotans regularly get bitten by the American dog tick, or wood tick, but don’t tend to get sick.
Rarely, they can cause Rocky Mountain spotted fever. Lone star tick bites are seldom found in Minnesota but can have severe complications. However, Schiffman said the Powassan virus hasn’t been known to cause canine sickness.
Could federal funding cuts affect disease detection?
Testing for Powassan isn’t as widely available as it is for other tick-borne diseases, in part due to its rarity. In Minnesota, it’s possible at the Mayo Clinic and MDH’s Public Health Laboratory.
By the time providers reach out for a Powassan test, they’ve ruled out pretty much everything else, Schiffman said. “So we’re kind of biasing toward those really more severe cases” in terms of numbers.
Federal funding slashes and their ripple effects could potentially affect the detection of diseases like Powassan.
“These tests are, they aren’t free and they do take resources,” Schiffman said. “Stuff like this is really a priority for us at the health department, and we will do our best. But it is possible, if the cuts continue, and they're severe enough, that things like this could be impacted in the future.”
Prevention is key
Now is the time of year to start thinking about these parasites. They arrive upon snow melt, peak in late spring to early summer, and then rally for a second spike in the fall.
“The ticks are out enjoying the spring weather, just like we are,” Schiffman said. “When you’re outside in wooded and brushy areas, in particular, knowing to do tick checks, wearing an effective repellent, just doing all the things, even like pulling your socks up over your pants, is helpful.”
MDH says DEET-based repellents and EPA-regulated products containing permethrin are effective. Veterinarians can advise on a variety of tick deterrents for furry friends. Maintaining lawns and trails, cleaning up brush and leaves and making a barrier between your grass and nearby woods can also help to prevent ticks.
If you find a tick on you or your pet, remove it as quickly as you can. MDH offers a short video on how to do so.