BOSTON, Mass. (WWLP)-- A 12th human case of West Nile virus (WNV) has been found in Massachusetts. According to the Massachusetts Department of Public Health (DPH), a man in his 50's was exposed in Essex County. No animal cases have been detected yet this year. Both EEE and West Nile Virus pose a threat to Massachusetts: How to protect yourself “This has been an active year for mosquito-borne disease, including West Nile virus,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “The risk for disease will continue until the first hard frost, so we continue to recommend that people take steps to protect themselves.” The DPH reports that across the state so far this year, there have been 330 WNV-positive mosquito samples found in Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties. Last year, there were six human cases of WNV and no animal cases.  Health officials say the best way to prevent infection to WNV and other mosquito borne illnesses is to reduce skin exposure by wearing long pants and shirts when outside, especially between dusk and dawn, and to use an insect repellent.