Two new human cases of West Nile virus confirmed in Massachusetts, bringing total to 6

Two more people in Massachusetts have been diagnosed with West Nile virus, bringing the total number of human cases in the state this season to six, public health officials said.

The Massachusetts Department of Public Health announced two new cases Tuesday. One is a man in his 50s who was exposed in Suffolk County, and the other is a man in his 80s who was exposed in southern Middlesex County.

Because of the new cases, the state said it is raising West Nile virus risk levels to high in Saugus, Arlington, Belmont, Malden, Medford, Melrose, Chelsea, Revere and Winthrop.

“The risk of West Nile virus infection in Massachusetts will persist until the first frost,” Public Health Commissioner Robbie Goldstein said in a statement. “While temperatures may be a bit cooler, September is still within the peak period of West Nile virus activity in Massachusetts. As we all adjust to our post-summer schedules, one routine everyone should continue to follow is using mosquito repellent when outdoors.”

In 2023, there were six human cases of West Nile virus infection in Massachusetts, and no cases in animals. So far in 2014, no animal cases have been reported.

The state said that so far this year, 286 mosquito samples have tested positive for West Nile virus in Barnstable, Berkshire, Bristol, Dukes, Essex, Hampden, Middlesex, Norfolk, Plymouth, Suffolk and Worcester counties.

Public health officials stressed that residents have an important role to play in protecting themselves and their loved ones from mosquito-borne diseases like West Nile virus, which can cause severe symptoms in older adults. Most people recover on their own without treatment and have no symptoms of illness, but others may develop headaches, fever, vomiting or body aches, officials said.

The state has a map tracking mosquito-borne disease risks in Massachusetts and has urged the public to take the following steps as the season continues:

• Protect your pets by eliminating standing water around your property and contact your veterinarian about mosquito repellents approved for use on animals or vaccines available to protect against diseases they can transmit.

• Avoid mosquito bites by using insect repellent, avoiding peak mosquito times (dusk to dawn), and wearing clothing such as long pants that can help keep insects away from your skin.

• Protect your home from mosquitoes by draining any standing water, such as bird baths or unused flower pots where mosquitoes could lay their eggs, and install screens to prevent insects from entering the home.