June 26, 2024

Elk Grove, Ca— The Sacramento-Yolo Mosquito & Vector Control District announced today that the first mosquito sample of the season has tested positive for West Nile virus in Yolo County. The mosquito sample was collected near the town of Dunnigan and follows the detection of a dead bird that also tested positive for the disease in Woodland earlier this month. “This is a clear sign that West Nile virus activity is spreading,” said Gary Goodman, District Manager. At the same time, West Nile virus activity continues to gradually increase as more dead birds and mosquito samples collected from Land Park and other areas throughout the city of Sacramento also tested positive this week.   “With the warmer temperatures we’ve seen recently West Nile virus activity is steadily rising,” indicated Goodman.  “We are heading into one of the hottest months of the year and it’s extremely important that residents continue taking proper precautions to protect themselves from mosquitoes.” Last year in California there were 433 confirmed human cases of the disease, including 19 fatalities. 
In response to the recent findings, the District will continue to monitor all West Nile virus activity through widespread mosquito trapping and testing as well as perform ground treatments in areas where positive mosquitoes have been found to quickly decrease populations and protect public health. 
Another ongoing concern is the spread of invasive mosquitoes throughout the District.  Aedes aegypti were detected for the first time within District boundaries in 2019 and Aedes albopictus were first found in 2022.  This year invasive mosquitoes have already been found in different areas throughout the District.  Invasive mosquitoes aggressively bite during the day and pose a significant health threat because they can transmit dangerous viruses including Zika, dengue fever and chikungunya.
To see a complete map of the WNV findings and for current information about District activities, please visit:
Residents may also subscribe to mailing lists to receive email notifications for upcoming mosquito treatments by zip code. To sign up, go to Spray Notifications on the website at
2024 West Nile virus activity update:
Sacramento County:  17 dead birds and 10 mosquito samples have tested positive for West Nile virus to date. 
Yolo County:  1 dead bird and 1 mosquito sample have tested positive for West Nile virus