While state officials await test results from two suspected cases of mosquito-borne viruses in humans, a school district in York County has sprayed pesticides at elementary school properties to protect students.

Responding to a report in mid-August that West Nile virus had been identified in a mosquito sample in Lebanon, school officials there decided to “be on the side of caution” and authorized spraying of the edges of the two elementary school properties, said Jim Ashe, interim superintendent.

The spraying Wednesday morning was a “proactive” measure to protect children as young as 6 through middle-schoolers, who will return to school Sept. 6.

The spraying covered a swath about 4 to 5 feet wide on the perimeter of the grounds of the town’s two elementary schools, Hanson and Lebanon, which are separated by a 100-foot-wide thicket of woods with a brook — prime mosquito habitat.

Neither the playgrounds nor the buildings were sprayed, Ashe said, but officials felt margin spraying would create a wall of repellent that could serve as a buffer from insects.

The state Center for Disease Control and Prevention still was waiting late Monday for the results of tests on two suspected cases of mosquito-borne disease. One, being tested for West Nile virus, is believed to have been contracted in another state, CDC officials have said. The other case is a suspected Eastern equine encephalitis infection.

State epidemiologist Stephen Sears said he expects no word until late this week from the federal laboratory that’s doing the tests.

With the start of school, more children will be out early in the morning, and student athletes will be practicing or playing games in the late afternoon and evening. Dawn and dusk are mosquito-heavy times of the day, so school and health officials feel some extra attention and protection is wise.

“It’s fairly prudent to do something,” said Jim Dill, a pest management specialist with the University of Maine Cooperative Extension. “Protection is the best thing.”

Applying pesticides, he said, is “kind of a last resort,” particularly now in Maine, because no cases of mosquito-borne disease have been confirmed in humans; but “it’s better to be safe than sorry.”

Dill called the spraying in Lebanon “due diligence” on school officials’ part. “If you save one person, it’s worth it.”

“We’re always going to be a little more proactive” when the public health issue concerns young children, said Superintendent Ashe. “We were just trying to be protective.”

The pesticide was applied by two truck sprayers dragging hoses a few hundred feet long, said Kevin Moore, facilities manager for the school district, Regional School Unit 60.

Ashe did not rule out additional spraying. Pesticides have not been used at any other school properties in the district, which includes Lebanon, North Berwick and Berwick.

Everything depends on whether the virus turns up in humans or appears to be spreading farther, Ashe said.

He said the district would take its lead from the local health department.

Another consideration for school officials who decided to spray was the community’s use of school playgrounds and fields, said Moore.

One of Maine’s confirmed cases of West Nile virus in a mosquito was detected in Gorham. Several calls to Gorham school officials weren’t returned Monday, so it wasn’t known whether they are considering using pesticide.

Some entomologists and consumer watchdogs have opposed the use of pesticides for West Nile virus vigorously, citing what they see as minimal risk from the disease and hazards of pesticide use.

Many pesticides kill insects indiscriminately, including bees. Colony collapse disorder has wiped out an estimated 90 percent of the wild bee population in the U.S., along with 70 percent of the wildflowers that depend on pollination.

Public health officials in Maine have advised people not to panic about West Nile virus but to take common-sense precautions, including staying indoors from dusk to dawn, wearing long-sleeved shirts and long pants, avoiding areas of stagnant water and low wind, and using appropriate insect repellent.

Dill, with the University of Maine Cooperative Extension, envisioned another approach: suspending all outdoor activities, including Friday night football games, soccer games and other sports, until mid- to late October, when mosquitoes would be killed off by a couple of hard frosts.

That plan would be effective, he said, but probably not popular.