West Nile Risk Now Higher In 5 MetroWest Communities: State

WAYLAND, MA — For the first time this summer, state health officials have increased the risk of West Nile virus to "moderate" in Wayland, Marlborough, Sudbury, Natick and Framingham.

The increase comes after multiple mosquito samples tested positive for the rare but potentially serious disease. The state has confirmed just under 100 West Nile samples statewide so far this season, including mosquito samples captured in Framingham on July 30, Marlborough on July 19, and in Natick and Wayland in early July.

Most of Massachusetts is still at "low" risk of West Nile as of Tuesday, according to state maps. There are several larger clusters at "moderate" risk including communities around Worcester, Burlington, Boston and across Bristol and Plymouth counties. The state also confirmed the first human West Nile case on Tuesday: a man in his 40s from Hampden County. An animal in Plymouth County also tested positive for Eastern equine encephalitis.

According to health officials, about 80 percent of people infected with West Nile don't develop symptoms, but about 20 percent will suffer symptoms like fever, rashes, nausea and vomiting, headaches and body aches. About 1 percent of cases can develop potentially serious encephalitis or meningitis. People over age 50 are thought to be at greatest risk.

"Because most people who are exposed to WNV have no symptoms, it is difficult to know exactly how many people have been infected," according to the state. "Between 2014 and 2023, 131 people were reported with WNV infection in Massachusetts. Eight of these people died. Cases have been identified from around the state."

The risk of Eastern equine encephalitis (EEE) in the area is still "low," according to the state. There have been recent samples collected in northern Essex County and in the Middleborough area. Those places have either "moderate" or "high" risk of EEE.

As usual, local health officials are reminding residents to guard against mosquito bites by using repellent with EPA-registered ingredients like DEET, permethrin (cannot be applied directly to skin), picaridin and oil of lemon eucalyptus. Residents should be extra cautious during dawn and dusk, when mosquitoes are most active.