Massachusetts health officials have announced a second confirmed case of the mosquito-borne eastern equine encephalitis virus in the state. A second confirmed case of the virus in a horse was also announced Thursday. The human case is a woman in her 30s. Both were exposed in the area of Plymouth County that was aerial-sprayed Tuesday night. Both became infected before spraying was performed. The detection of the latest case comes after a New Hampshire resident infected with the virus died, state health authorities said Tuesday. Massachusetts Public Health Commissioner Robbie Goldstein said people should take steps to prevent mosquito bites.