West Nile virus has been detected in two mosquito samples in Umatilla County, one east of Umatilla and one on the southern edge of Stanfield.

The samples were collected June 28, and testing was done at the Oregon State University Veterinary Diagnostic Laboratory on July 6. It’s the first detection of West Nile in Oregon so far this year.

Residents can expect an increase in mosquito control operations, including Ultra-Low Volume applications of insecticide from truck-mounted sprayers. Spraying will typically be done after sunset, when mosquitoes are most active. All applicators are licensed by the Oregon Department of Agriculture.

West Nile is primarily a bird disease, with magpies, blue jays and crows especially susceptible. Mosquitoes feed on infected birds and can pass the virus to humans or other animals when they bite. Most people infected with West Nile do not become sick, but some may develop mild flu-like symptoms and, in rare cases, the virus may cause encephalitis, or inflammation of the brain.

The risk of West Nile is low, but the public is encouraged to take precautions against mosquito bites. People can reduce their exposure to mosquitoes by avoiding outdoor activities at dawn or dusk, when mosquitoes are active, using mosquito repellent or wearing long-sleeved shirts and pants when working in mosquito-infested areas.

Other tips include screening doors and windows, and getting rid of old tires or other containers where water can accumulate and serve as a breeding ground for mosquitoes. Those with horses should check with their veterinarians for vaccinations, and be sure to flush or replace the water in their troughs weekly.

For more information and updates on West Nile, visit www.public.health.oregon.gov or call the Umatilla County Health Department at 541-278-5432.