State health officials say a third horse has died in Massachusetts this summer because of mosquito-borne Eastern equine encephalitis.
The 3-year-old horse from Lancaster is the second to die in Worcester County. The state health department said Thursday that lab results confirmed EEE in the horse that died Aug. 13, a day after showing symptoms. A horse from Warren was euthanized Aug. 1 because of the diease. and a horse from Middleborough was euthanized in July.
A Rhode Island man was confirmed last weekend as having the virus, which officials say he probably contracted in southeastern Massachusetts, an area of high risk from mosquitoes. He was hospitalized in critical condition.
Massachusetts had last reported a human case in 2008 and Rhode Island in 1998.