More Mosquitoes In Worcester Test Positive For West Nile: State

WORCESTER, MA — More mosquitoes collected in Worcester have tested positive for West Nile virus, state health officials have confirmed.

Samples collected on Aug. 1 and 2 tested positive for the potentially serious virus. Mosquitoes collected in traps in Worcester previously tested positive on July 25 and July 19.

The Worcester area is now rated as having a "moderate" risk of West Nile, which is higher than most parts of the state, according to Department of Public Health risk maps. The Boston area, Framingham area and large parts of Bristol and Plymouth counties are also at "moderate" risk.

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 state has confirmed 116 positive West Nile samples in mosquitoes so far this summer. 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.

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.

The Central Massachusetts Mosquito Control Project will be out spraying in the areas where the most recent samples were confirmed — in neighborhoods around Shrewsbury Street, and along Grove Street east of Institute Park — on Wednesday evening.