The agency explains the chain plainly: a case only appears in the national count if a doctor suspected West Nile, tested for it, and reported it. On its West Nile data page, the department states that monitoring for infected mosquitoes is "limited to a few counties due to lack of resources." Through this season, West Nile has been detected in mosquitoes in Benton, Grant and Yakima counties 22 times, according to reporting by the Spokesman-Review. The same reporting describes little to no mosquito screening in northern or southeastern Washington, with many rural communities lacking established mosquito control districts. A mosquito control district is a local taxing and operating body that runs trapping, testing, and larval control.