Ada County has become the fifth county in southwestern Idaho where West Nile virus has been identified in local mosquitoes. No human cases have been reported so far this year, but last year Idaho had 13 human cases of the virus, with five of those suffering neuroinvasive infections. The virus can cause severe illness, especially in people over age 50.

The other four counties in the region where the virus has been confirmed in mosquitoes so far this summer are Canyon, Gem, Payette and Owhyee. The state Department of Health & Welfare has more info here.