SUTTER-YUBA REGION, CA (MPG) - The Sutter-Yuba Mosquito and Vector Control District has confirmed the first evidence of West Nile virus (WNV) activity in both Yuba and Sutter Counties for 2025.

Two mosquito samples collected on July 8 tested positive for the virus, one from the Linda area in Yuba County and another from the South Yuba City area in Sutter County.

To date, there have been no confirmed detections of West Nile virus in dead birds, sentinel chicken flocks, or human cases in either county.

With recent hot weather accelerating mosquito development, surveillance traps are showing an increase in the population of Culex mosquitoes, the primary vectors of West Nile virus.

The district’s surveillance program remains fully active and mosquito control operations are being conducted in areas where virus activity has been detected.

The district urges residents to take preventative measures, as avoiding mosquito bites is the most effective way to protect yourself and your family from West Nile virus and other mosquito-borne illnesses. The following “4 D’s” of mosquito prevention are simple, but essential steps. Defend, dawn and dusk, doors and windows, and drain standing water.

Use insect repellents containing DEET, picaridin, oil of lemon eucalyptus, or IR3535 to defend against mosquitoes. These EPA-registered ingredients are proven to be effective in preventing bites. Always follow product instructions, especially when applying to children. Visit the EPA Repellent Search Tool for more information.

Limit outdoor activities during dawn and dusk when mosquitoes that transmit West Nile virus are most active. If you must be outdoors, wear long sleeves and pants for added protection.

Ensure that window and door screens are intact and in good repair to prevent mosquitoes from entering your home.

Mosquitoes lay eggs in standing water. Regularly empty containers such as flowerpot saucers, buckets, tires, and birdbaths. Report neglected or green swimming pools to the district.

Residents are also encouraged to report dead birds, which are early indicators of West Nile virus activity, to the California Department of Public Health at https://westnile.ca.gov or by calling 877-968-2473.

For more information, please visit our website at https://sutter-yubamvcd.org.

For questions regarding this detection, contact the district office at 530-674-5456 ext. 0, Monday through Friday, between 7:00 a.m. and 3:30 p.m. excluding holidays.