CALDWELL -- Officials say the number of mosquitoes testing positive for West Nile Virus has climbed sharply in the Treasure Valley region.

Canyon County Mosquito Abatement District Director Ed Burnett says the number of infected mosquitoes in the region is estimated to be roughly ten infected insects in every thousand mosquitoes.

The county will begin aerial spraying for the mosquitoes next week. But Commissioner Steve Rule says that residents need to be extra careful until the spraying is completed.