SAUGUS — Director of Public Health John Fralick spoke at a Board of Health meeting regarding the town’s high risk level for West Nile virus.

“Lower Essex County has been raised to a high risk level as of last week,” Fralick said, due to several cases in Middlesex and Suffolk counties.

“Kind of the whole greater Boston area has been raised to a significant risk level, until the end of the arbovirus season,” Fralick said.

Fralick said that the arbovirus season typically ends in mid to late October, which is marked by the first “hard frost” of the season. This occurs when nighttime temperatures reach either two nights in a row of 28 degrees Fahrenheit or less, or three nights in a row of 32 degrees Fahrenheit or less.

“Once we see some frost on the ground, you see your breath in the morning, that’s when you know… the risk level will probably start coming down,” Fralick said.

Fralick said that throughout the state, so far there have been seven cases of West Nile virus this year, none within town.

He added that another mosquito-borne illness, Eastern equine encephalitis (EEE), has had four human cases in the state. He said these illnesses will be an “ongoing risk” for the community.

Fralick stressed the importance of the existing literature on precautionary measures that residents can take.

“I think at this point, everybody has heard the rhetoric as far as the types of precautions…as far as wearing bug spray, limiting your dusk activities, and wearing long pants and long sleeves… making sure that there’s no standing water on your properties, and making sure your screens are all intact in your homes,” Fralick said.

“It’s something that we’re really trying to make sure folks are aware of, just because… it’s going to be an ongoing thing until the end of the season,” he added.

Fralick said that government agencies have been working to make sure that residents are prepared, adding that the Department of Agriculture has been doing work across the state to “keep us more prepared for the reason of the season.”

He stressed that it is important to remain vigilant throughout the remainder of the arbovirus season.

“It’s nice, it’s fall, leaves are changing, that kind of thing — but we just want to make sure that everybody’s staying vigilant while we’re getting into the end of this season,” Fralick said.

Board of Health Chair Maria Tamagna said that just because the risk level has been raised to high, it does not necessarily mean there have been more positive mosquito samplings.

“It means that we have reached that threshold of high, and once your town, your city or town, reaches that threshold, we’re going to stay there,” Tamagna said.

Fralick said that the Northeast Mosquito Control Board has been conducting residential spraying treatments for mosquitos by request. He added that residents interested in doing so can make a request for treatment via the town’s website.

“They’ve been using an ultra low-volume aerosol sprayer,” Fralick said.

He added that the spraying deals with live mosquitos, and there are additionally larvicide treatments being done at catch basins around town.