Aside from the pending investigation, there has only been one case of Powassan virus on the island in the past 20 years.

A tick-borne illness has been spotted in a Martha's Vineyard resident, making it the third diagnosis in the United States this year.

The potential case comes during one of the worst tick seasons in New England in years, with a surge of tick-borne diseases and tick exposures. Only one case of Powassan virus has been recorded on Martha’s Vineyard in the past 20 years, officials said. So far this year, three cases have been confirmed in Massachusetts.