A Franklin County resident has died after testing positive for West Nile virus, the first death linked to the disease in Washington state this year, the Benton-Franklin Health District said this week.
The resident was older than 70 and had underlying health conditions that increased the risk of severe illness, according to the health district, as reported by AppleValleyNewsNow. The district has not released the person's name, hometown or exact date of death.
"We send our sympathies to the family of our Franklin County community member," Dr. Steven Krager, the health officer for Benton and Franklin counties, said in a written statement. "There is no vaccine or specific treatment for West Nile virus disease, so our best course of action is prevention. Take precautions to avoid mosquito bites, especially as warm weather continues and mosquitoes remain active."
The death is the fourth West Nile virus case BFHD has identified in the two-county area in 2026.
A season that started with dead crows near Prosser
The virus first showed up locally in June, when a state Department of Transportation worker mowing roadside grass near Prosser began finding dead crows and reported them to the local mosquito control district. Testing confirmed West Nile virus in four crows recovered over several days, Annette Cary reported for the Tri-City Herald in a story carried by the Yakima Herald-Republic. At that point no Tri-Cities-area resident had been reported infected since 2021, according to state Department of Health data cited in that report.
That changed in late August, when BFHD confirmed the first human case of the year, a Benton County resident whose infection health officials believe came from a local mosquito bite. "This is the first case of West Nile Virus disease with local transmission in Washington State this year," Krager said in a statement at the time, according to AppleValleyNewsNow.
A Franklin County resident tested positive in September, around the same time testing confirmed the county's first West Nile-positive mosquito pool since 2021, AppleValleyNewsNow reported. This week's death brings the local case count to four for the year, though it's not clear from BFHD's public statements exactly how that tally splits between Benton and Franklin county residents, or whether additional Washington cases have since been confirmed elsewhere by the state Department of Health.
Why the risk doesn't end with cooler weather
Most people infected with West Nile virus never feel sick. About one in five develop fever, headache, body aches, joint pain, vomiting, diarrhea or a rash, according to BFHD's health topic page. Roughly one in 150 infections turns serious, causing encephalitis or meningitis, and that risk is highest for people over 60 and those with weakened immune systems.
BFHD notes that West Nile virus is the leading cause of mosquito-borne disease in the continental U.S., with cases typically running from early summer through fall — meaning mosquitoes in the Tri-Cities can still pose a risk as temperatures start to drop in October. The health district is urging residents to keep using repellent, wear long sleeves during dawn and dusk hours when mosquitoes are most active, and drain any standing water around homes and yards where mosquitoes breed.
It's not yet clear when area mosquito control districts plan to wind down seasonal trapping and spraying for the year. Residents with questions about local mosquito activity or testing can contact the Benton-Franklin Health District directly.
