First Fresno County West Nile virus sign found in dead bird

Fresno County health officials said a dead bird collected in the city of Fresno tested positive for West Nile virus, the county’s first sign of virus activity this year. The California Department of Public Health notified local authorities, and Fresno County Health Officer Dr. Trinidad Solis said the positive bird shows the virus is already circulating in the community.

That early signal matters because West Nile activity typically builds through the summer and into the fall, according to the Centers for Disease Control and Prevention. California’s surveillance system tracks dead birds, mosquitoes, human cases and infections in other animals so public-health workers can spot a problem before it shows up in emergency rooms or hospital wards.

In Fresno County, the timing is notable. Last year, the county’s first West Nile detection came from mosquito sampling on June 25, 2025, and officials later confirmed the county’s first human West Nile death of the year. This year’s first detection arrived earlier, through a dead bird, on May 15, giving health crews an earlier neighborhood-level warning that mosquito activity is underway.

County officials are urging residents to cut risk now by using approved insect repellents with DEET, picaridin, oil of lemon eucalyptus or IR3535, especially at dawn and dusk when mosquitoes that spread West Nile are most active. They also want people to drain standing water from flowerpots, tires, buckets and other containers, check window and door screens, and eliminate runoff or other spots where water can collect. Neglected swimming pools remain a major source of mosquito production in urban and suburban areas, and Fresno County’s mosquito-control system includes different districts across the county that residents can contact about mosquito problems.

Officials are also asking people to report dead birds through the California West Nile Virus website or by calling the West Nile call center at 1-877-WNV-BIRD, or 1-877-968-2473. Dead-bird reports can be submitted online year-round, and by phone from April through October. With California now documenting more than 8,000 West Nile infections and more than 400 deaths since 2003, county leaders are treating the dead bird as a warning to tighten up the usual summer defenses before human cases appear.