11th West Nile Virus Case Confirmed In MA, EEE Risk Levels Raised

MASSACHUSETTS — The 11th human case of West Nile virus in Massachusetts this year was confirmed Friday, according to the Massachusetts Department of Public Health.

The person is a man in his 60s with recent out-of-state travel, meaning the exact location of exposure is uncertain, health officials said. However, there is a possibility he could have been exposed within the Greater Boston area, which is already known to be at high risk for WNV.

Both West Nile virus and Eastern equine encephalitis, another virus affecting people in Massachusetts this season, are transmitted to humans through the bite of an infected mosquito.

The Department of Public Health has also raised the risk level of EEE to high in Concord due to two consecutive weeks of EEE-positive mosquito findings in species known to be able to spread the virus to humans, according to officials.

See also:

• 3 New MA West Nile Virus Cases Confirmed As Mosquito-Borne Illness Worries Escalate
• West Nile Virus Alert: 8 MA Communities Now 'High Risk'

This is an expansion of an area already considered to be at high risk from EEE, officials said. In addition to 11 West Nile virus cases, there have been four confirmed human cases of Eastern equine encephalitis in Massachusetts this season.

A total of 314 WNV-positive mosquito samples have been detected so far this year from Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties, officials said earlier this week. There have been 95 EEE-positive mosquito samples, four human cases, and two horse cases reported in Massachusetts so far this year.

"It may be mid-September, but warm and humid weather continues across Massachusetts, keeping the risk of both EEE and West Nile elevated," Public Health Commissioner Robbie Goldstein, MD, PhD. said.

Goldstein said Tuesday that "West Nile virus does not always raise as much concern as EEE, but it remains a potentially very serious disease, especially for those over the age of 60 or with certain medical conditions, such as cancer, diabetes, high blood pressure, kidney disease, or an organ transplant."

The last outbreak of EEE in Massachusetts occurred in 2019-2020 and resulted in 17 human cases with seven deaths. In addition to this year's four human cases, EEE has also been identified in two horses in Massachusetts.

Residents throughout the state are advised to avoid going outdoors, especially in wooded areas, around the hours of dusk and dawn when mosquito activity is highest and to wear long clothing when out at those times.

The state DPH advised the use of a repellent with DEET, permethrin, picaridin, or oil of lemon eucalyptus, according to the instructions on the product label.

Residents are also asked to clear standing water on properties that can be used as mosquito breeding areas.

"There will continue to be risk from mosquito-borne disease until the first hard frost, and I encourage everyone to continue to take measures to protect themselves," Goldstein said.