Mosquito spraying was done Monday night in Saugus after mosquitoes were found carrying the West Nile virus, according to an e-mail from the board of health. The chemical, used on an area between Winter and Hamilton Streets, was a low dosage and posed no threat to humans. Fields at the Belmonte and Waybright Schools were not sprayed.

“They do weekly testing; they have traps set up throughout Saugus,” said Frank Giacalone, director of public health, referring to the Northeast Massachusetts Mosquito Control, a state agency that works at preventing the spread of diseases carried by mosquitoes. He added that they mainly test for West Nile virus and Eastern Equine Encephalitis (EEE).

According to a public health fact sheet on EEE put out by the Massachusetts Department of Public Health, EEE is rare—with under 100 cases since it first arrived in 1938—but there’s no treatment, and survivors “will often be permanently disabled,” according to the fact sheet. West Nile virus, according to another fact sheet, also has no treatment, but 80% of people infected will have no symptoms; less than 20% will have fever, nausea, and swollen lymph glands; and less than 1% will get serious symptoms, like meningitis or encephalitis.

“We haven’t had a normal year. We had a very mild winter and a very mild spring,” Giacalone said, adding that those are much better conditions for mosquito breeding.

He also said that no one, so far, had gotten either disease, but Saugus does have plans from the control agency for dealing with mosquitoes. “They fine tune the program for the community,” Giacalone noted.