PRESS RELEASE

The Yolo County Health and Human Services Agency’s (HHSA) Communicable Disease Program has confirmed the county’s first human case of West Nile virus in 2025. The individual, a Davis resident, was hospitalized for their illness. This case is one of 15 reported statewide this year, making Yolo County the seventh county in California to confirm a human infection. It also serves as a reminder that mosquitoes in Yolo County can carry West Nile virus, and residents are urged to take precautions to protect themselves from mosquito bites.

"Just one bite from an infected mosquito can transmit West Nile virus,” said Yolo County’s Public Health Officer, Dr. Aimee Sisson. “Most people who become infected don’t get sick, but about one percent of individuals develop a serious neurologic illness. When you protect yourself against mosquito bites, you protect yourself against West Nile virus. Applying mosquito repellent and wearing loose clothing that minimizes bare skin, especially around dawn and dusk, are great steps to fight the bite.”

West Nile virus symptoms typically show up 2 to 6 days after a bite from an infected mosquito. Although most individuals do not have symptoms, up to 20 percent of infected people may experience fever, headache, body aches, nausea, or vomiting. While most cases resolve within a few days to weeks, serious neurologic effects can occur, resulting in hospitalization and sometimes death. Severe illness is more common in older adults, people with weakened immune systems, and those with chronic medical conditions.

To reduce the risk of West Nile virus infection, the Sacramento-Yolo Mosquito & Vector Control District recommends following the 7 D’s of mosquito prevention:

• DRAIN any stagnant water to eliminate mosquito breeding sites.

• DAWN and DUSK, when mosquitoes are most active, are times to limit outdoor activities.

• DRESS in long sleeves and pants when outdoors.

• DEFEND against mosquitoes by using effective insect repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus.

• Ensure DOOR and window screens are intact to prevent mosquitos from entering homes.

• For assistance, contact the DISTRICT at 1-800-429-1022 to address mosquito concerns.

“This first human case is a strong reminder that West Nile virus is active in our area,” said Gary Goodman, District Manager of the Sacramento-Yolo Mosquito & Vector Control District. “We are working diligently to control mosquito populations and reduce the threat of West Nile virus, but we cannot do it alone. Residents play a critical role by eliminating standing water around their homes and using repellent when outdoors. Together, we can help reduce the risk of West Nile virus in our communities. If you are experiencing mosquito problems around your home, please give us a call so we can help.”

The Sacramento-Yolo Mosquito & Vector Control District has been implementing comprehensive control measures to reduce mosquito populations in Yolo County, minimizing the risk of disease transmission.

Additionally, HHSA offers a Wellness Vending Machine Program that provides free wellness products to residents, including insect repellent. For vending machine locations, please visit www.YoloCounty.gov/Wellness-Vending-Machine.

For more information and resources, visit the Sacramento-Yolo Mosquito & Vector Control District's website at www.FIGHTtheBITE.net or call 1-800-429-1022. For more information about West Nile virus in California, including data and statistics, please visit WestNile.ca.gov.