State health officials say they have detected Eastern Equine Encephalitis in a mosquito pool collected in Bridgewater.
The Department of Public Health said the pool was collected on July 15.
The nearby towns of West Bridgewater, Easton, Raynham and Middleborough are already at moderate risk level based on last year’s EEE activity, the DPH said.
There have been no human cases of West Nile virus or EEE in Massachusetts this year. There was one case of EEE last year among Massachusetts residents.
EEE is spread to humans through the bite of an infected mosquito. Initial symptoms of EEE are fever — often 103 to 106 degrees Fahrenheit — stiff neck, headache and lack of energy; in severe cases, symptoms can progress to confusion, disorientation and coma.
West Nile virus is usually transmitted to humans through the bite of an infected mosquito. Most people infected with West Nile virus will have no symptoms. West Nile virus symptoms tend to include fever and flu-like illness, but in rare cases, more severe illness can occur.