August 21, 2023

Contact:  Luz Maria Robles, Public Information Officer
Office:  916-405-2082 |  Cell:  916-416-6337


–Davis is an area of concern
Elk Grove, Ca— The Sacramento-Yolo Mosquito and Vector Control District continues to closely monitor the spread of West Nile virus as activity remains intense and widespread throughout Sacramento and Yolo counties.  Laboratory test results for last week confirmed 83 mosquito samples tested positive. This is a sharp increase, especially in Davis and Woodland where much of the activity is concentrated. “This is a record year for West Nile virus activity and the threat of becoming ill is very real,” said Gary Goodman, District Manager. Recently, the first human case of West Nile was confirmed in Yolo County.  “We are very concerned about the intense activity, especially since we are still in the middle of the summer and typically we don’t see a decrease in mosquitoes until mid-September,” added Goodman. West Nile virus is transmitted by the bite of an infected mosquito and can cause serious illness in older people and those with a compromised immune system. One in five people develop fever with other symptoms such as headaches, joint pains, body aches, vomiting and diarrhea. One in 150 people develop the severe form of the disease affecting the central nervous system which can result in death.
Earlier this month, the District conducted aerial spraying to combat mosquitoes and West Nile virus over the cities of Davis and Woodland in Yolo County. Laboratory surveillance efforts show that the abundance of mosquitoes and infection rates were reduced significantly in these areas. However, due to an increase in agricultural sources surrounding both of these cities and a record amount of rain last winter that created a variety of breeding sources, mosquito populations continue to be abundant.
In response to the ongoing West Nile virus activity and in effort to reduce the overall number of mosquitoes that pose a threat, the District has intensified ground mosquito control treatments around parks, neighborhoods and agricultural. These efforts will continue for a few more weeks. Based on the ongoing activity, additional aerial treatments over the cities of Davis and Woodland are still being considered.

Throughout the state, West Nile virus activity is also on the rise. To date, there are 26 confirmed human cases from 12 different counties. Last year there were a total of 221 human cases including 15 fatalities.
For current information about any treatments planned, please visit Residents may also subscribe to mailing lists to receive email notifications for mosquito treatments by zip code. 
2023 West Nile virus activity update:
Sacramento County:  237 mosquito samples and 120 dead birds have tested positive for West Nile virus to date.
Yolo County:  251 mosquito samples and 26 dead birds, have tested positive for West Nile virus to date

Practice the District D’s of Mosquito Prevention: 

DRAIN standing water that may produce mosquitoes. 
DAWN and DUSK are times to avoid being outdoors.   
DRESS appropriately be wearing long sleeves and pants when outside. 
DEFEND yourself by using an effective insect repellent.  Make sure to follow label directions! 
DOOR and window screens should be in good working condition.
DISTRICT personnel are also available to address any mosquito problems. Call them at 1-800-429-1022 or visit