Dead birds in Benton County. 1st West Nile virus in WA in 2026
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- One type of dead bird tested positive for West Nile virus.
- No human or horse cases from mosquito bites in Washington yet this year.
- A plane and trucks will spray insecticide Thursday in parts of Benton County.
West Nile virus has been detected for the first time this year in Washington state in dead crows in Benton County, says the Benton County Mosquito Control District.
A Washington state Department of Transportation employee mowing in Prosser began noticing dead crows and reported them to the mosquito control district, said Angela Beehler, district manager.
The district arranged for testing of four crows found over several days, and all were positive for the virus, she said.
The district also has begun collecting trapped mosquitoes, but the crows were tested first and no results for mosquitoes are available yet.
Although most birds survive the infection, the virus frequently kills crows and jays, according to the Centers for Disease Control and Prevention.
Infected birds can develop high levels of the virus, spreading it to mosquitoes that bite them. The infected mosquitoes can then spread the virus to people and other mammals, including horses.
The virus is not known to have spread to people and horses yet this year in Washington state, although one person in the state was infected during a visit to Arizona, Beehler said.
A Tri-Cities area resident has not been reported to be infected with West Nile virus since 2021, according to Washington state Department of Health data.
Only about one in five people infected with the virus will develop a fever and other symptoms such as headache or body aches, joint pains, vomiting, diarrhea or rash.
However, in about one in 150 cases are serious, resulting in encephalitis, meningitis or other complications that can lead to death.
The risk of severe disease is highest among people over 60. People with certain medical conditions that affect the immune system, such as cancer, diabetes, hypertension or kidney disease, are also at greater risk for serious illness, according to the Benton Franklin Health District.
A vaccine is available for horses, which can die from the virus, but there is not a vaccine for people.
West Nile virus prevention
Instead, people can take steps to prevent illness by avoiding mosquito bites and preventing mosquitoes from breeding.
To reduce the risk of infection, stay indoors at dusk and dawn, which are prime mosquito-biting times, says the health district.
If you go outside when mosquitoes are present, use an insect repellant approved by the Environmental Protection Agency. Wear loose-fitting, light-colored shirts with long sleeves, long pants and a hat.
Repair any holes or loose-fitting screens and don’t open windows, especially at night, if they do not have screens.
The Benton County Mosquito District plans to have a plane out for a couple of hours starting around sunset Thursday, June 11, depending on the weather, to spray an insecticide that kills adult mosquitoes in the West Richland area, Grandview and Mabton.
Truck spraying also will be done Thursday in West Richland and in parts of Richland, including Johnson Park and south of Jones Road.
Check the calendar and linked map at mosquitocontrol.org for details.
People also can drain standing water on their property that provides a place for mosquitoes to breed, including tires, buckets and other containers.