A serious tick-borne disease — other than Lyme — has established itself in southern Maine. Researchers from the Maine Medical Research Institute in Scarborough have found the Powassan virus in deer ticks across southern areas of the state.
The research was conducted after a midcoast woman died from the disease in 2013. In November of that year, 73-year-old Marilyn Ruth Snow was bitten by a deer tick infected with the Powassan virus. She fell ill almost immediately and died about a month later.
Her case was rare: according to the U.S. Centers for Disease Control, in the ten year period from 2006 to 2015, only 77 cases of Powassan were reported nationwide. Of those, 8 people died. But Snow’s death prompted researchers to find just how prevalent Powassan is here.
“We know with Lyme disease, we have rates of infection up to 60 percent in the tick population in certain parts of the state. But for Powassan, it was a real unknown for us,” says Chuck Lubelczyk, a vector ecologist at Maine Medical Research Institute in Scarborough.
In 2015 and 2016, researchers collected deer ticks across the state and tested them for the virus. Lubelczyk says they found that Powassan is readily present in one area of the state in particular.
“All of the ticks that we have found so far have been occurring in southern Maine, along a coastal stretch from MDI back to York County,” he says.
Though Powassan was not found in northern or eastern Maine, Lubelczyk says tick-borne diseases move, as evidenced by the spread of Lyme disease across the state over the past couple of decades.
Unlike Lyme disease, which tends to be transmitted most frequently in the summertime, Lubelczyk says Powassan is most often diagnosed from March to April, and October to December.
“This disease, Powassan virus, is just really another reason to really, really be careful of encountering ticks in the fall and early spring,” he says.
Though many people who become infected do not develop symptoms, Maine Center for Disease Control epidemiologist Dr. Siiri Bennett says the disease can have serious consequences.
“You can die from it, and it can cause seizures. Because it can cause encephalitis, an inflammation of the brain, and that’s why we’re concerned about it,” she says.
Bennett says to protect yourself against tick bites, wear repellent and long pants. It’s a good habit to protect against all tick-borne diseases, but Lubelczyck says it’s especially important for Powassan.
“The real scary thing about the Powassan virus is that unlike Lyme disease, which can be transmitted in 24-48 hours, laboratory studies indicate that Powassan virus is probably transmitted in under an hour,” he says.
And many Mainers spend much more time than that outdoors.