A Middlesex County man in his 70s has contracted eastern equine encephalitis (EEE). It's the fifth confirmed human case this year, according to the state Department of Public Health.
As a result, state officials raised the risk level in the towns of Ashland, Hopedale and Milford to critical. The risk level in Bellingham, Blackstone and Millville has been raised to high.
A Fairhaven woman died after contracting EEE in August. The other three human cases were detected in Worcester, Plymouth and Hampden counties.
Health officials urged the public to take individual steps to protect themselves, stressing that reducing exposure to mosquitoes by avoiding outdoors after dusk and by using repellent are among the best strategies
The five human cases of EEE this year are the first in Massachusetts since 2013. There have also been eight cases found in horses and one in a goat, officials confirmed.
Experts say EEE pops up in cycles in Massachusetts. Two separate outbreaks from 2004 to 2006 and from 2010 to 2012 saw 22 confirmed human cases.
Communities will continue truck-mounted mosquito spraying, but aerial spraying has ended for the season because evening temperatures are now too low for the process to work effectively.
Reporting from State House News Service was used in this report.