The Massachusetts of Department of Public Health posts information regarding mosquito-borne diseases in Massachusetts on their website at this link.
Information on their website includes:
In Medfield, the Norfolk County Mosquito Control District conducts regular spraying to reduce the mosquito population. They released this letter earlier this year with information about spraying. To request spraying on your street, visit their website.
No mosquitoes or animals have tested positive for EEE in Medfield to date in 2020.