The Maine Center for Disease Control and Prevention is reporting the state’s first case of the tick-borne Powassan virus since 2017.

The Powassan virus – which is rare but can cause severe illness – is much less common than other tick-borne diseases such as Lyme or anaplasmosis. Nationally, about seven cases are reported each year and this is just the 11th case of Powassan virus in Maine since 2000, the CDC said in a statement Wednesday.

Deer ticks, known for carrying the bacteria that causes Lyme disease, also carry the Powassan virus. Dill Griffin, Cooperative Extension

Maine typically has more than 1,000 confirmed Lyme cases annually, and hundreds more anaplasmosis cases. So far this year, Maine has reported 255 cases of Lyme, 327 cases of anaplasmosis and 36 cases of babesiosis, another tick-borne disease, through July 23, the Maine CDC reported.

The person who contracted the Powassan virus is an adult from southern Maine who has been hospitalized in New Hampshire, the CDC statement said. Health officials believe the patient contracted the virus in Maine. The New Hampshire Department of Health and Human Services notified the Maine CDC of the case this week. The state did not provide additional information, which is standard.

The Powassan virus is transmitted to humans through the bite of a deer tick or a woodchuck tick.

“Powassan, although rare, can be serious so it is important to be aware of your surroundings and take steps to avoid being bitten by ticks,” said Nirav D. Shah, director of the Maine CDC.


Symptoms include fever, vomiting, weakness, headaches, confusion, seizures and memory loss. The virus may cause long-term neurologic problems, and a severe infection can cause death.

The last cases of Powassan in Maine occurred in 2017, when two people contracted  the virus. Both were hospitalized with encephalitis but made full recoveries.

There is no medication to treat the Powassan virus infection, unlike Lyme disease, which is a bacterial infection that can be treated with antibiotics.

Griffin Dill, integrated pest management professional at the University of Maine Cooperative Extension, said he’s not sure why Powassan is so rare in comparison to other tick-borne diseases. The extension operates a “tick lab” and while the lab currently does not test for Powassan virus, it does test tick specimens for Lyme, anaplasmosis and babesiosis.

“As prevalence of pathogens grows, Lyme disease leads the charge, and then it’s later followed by increasing levels of other pathogens, like anaplasmosis and babesiosis,” Dill said. He said 7 percent of all tick specimens sent to the lab are co-infected, which means they have two pathogens, carrying both Lyme and anaplasmosis, for example.

The Maine CDC recommends a number of preventive measures to keep ticks at bay, including wearing light-colored, long-sleeved clothing and long pants when out in the woods or brush; using insect repellent; staying on the trails; bathing after being out in tick habitats and performing frequent “tick checks.”

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