(JOLIET) It’s getting cold and mosquitoes are scarce, so the Will County Health Department has suspended West Nile virus testing.

The department’s Division of Environmental Health closed its 14 mosquito monitoring sites Thursday because cooler weather means testing is no longer critical, according to a statement from the department.

Regular mosquito collections at the sites produced 407 test samples, including 62 that tested West Nile-positive, the health department said.

All testing sources confirmed 84 WNV-positive mosquitoes this season, a 67.8 percent spike from 2014, the department said.

“There is still some risk of WNV transmission to humans,” Health Department Executive Director John Cicero said in the statement. “The first hard frost will mitigate that risk. Until that hard frost occurs, people should continue to take precautions when spending time outdoors.”

Residents are encouraged to use insect repellent when going outdoors in the evening, and to wear long-sleeved shirts and long pants.

More than 70 percent of the department’s 2015 WNV-positive samples were collected from sites in Joliet and Bolingbrook. All but one monitoring site reported at least two virus-positive samples.