West Nile virus was detected in mosquitoes collected in Fall River, the Massachusetts Department of Public Health said Tuesday.
The mosquitoes were collected from an area near St. Patrick's Cemetery.
The Bristol County Mosquito Control Project will do ground spraying at St. Patrick's and Oak Grove cemeteries from 2 to 5 a.m. Thursday, weather permitting.
Fall River Mayor Will Flanagan said residents should keep their windows closed and stay inside during the spraying hours.
Mosquitoes infected with West Nile virus have been found in 10 of the state's 14 counties.
"These geographically widespread findings indicate that virus is circulating throughout the Commonwealth and is not confined to municipalities where infected mosquitoes have been found," a public health warning said.
Flanagan said residents need to take the usual precautions if they're outdoors during prime mosquito hours at dawn and dusk. Experts say wear long sleeves and long pants and use repellents with DEET.