Two human cases of West Nile confirmed in Yolo County. Both resulted in hospitalizations

Two cases of human West Nile virus infections have been confirmed in Woodland, marking the first cases of the mosquito-borne virus in Yolo County this year.

They both had to be hospitalized, the county said in a news release Thursday afternoon.

“Last year, several Yolo County residents died from West Nile virus infection,” Yolo County’s Public Health Officer, Dr. Aimee Sisson said in the release. “Mosquito bites aren’t just annoying — they can be deadly. Protect yourself with mosquito repellent and clothing that minimizes bare skin.”

Yolo County saw 45 total infections of West Nile in humans in 2023, three of which were fatal.

As of last Friday, the California Department of Public Health had confirmed nine human cases of West Nile this year in California, one of which was fatal. Overall, the amount of statewide cases in humans is lower this year to date than last year and the five-year average.

Yuba and Stanislaus counties both confirmed one human case of West Nile virus in July. Butte County has had two human cases of the virus.

Symptoms can appear between two and 14 days after infection and can be mild or flu-like, including fever, vomiting, body aches or headaches. More rare cases can lead to neurological illness and hospitalization.

“Most people who become infected after a mosquito bite do not get sick, and the risk of serious illness to most individuals is low. However, about one percent of individuals can develop a serious neurologic illness.”

80% of people infected with West Nile virus do not experience symptoms, according to the Centers for Disease Control and Prevention.

Reducing the risk of West Nile can be as simple as dressing in long sleeves and pants or limiting time outdoors when mosquitoes are most active, at dawn and dusk. Preventative measures also include draining stagnant water to eliminate breeding sites and using repellent.

Yolo County Health and Human Services has a wellness vending machine program that provides people with free wellness products, including mosquito repellent, the release said.

Data from the California Department of Public Health shows significantly fewer infected samples of mosquitoes this year compared with last year’s data at this point in the summer. 2024 has also seen less than the five year average, at 838 infected mosquito samples compared to the five-year average of 1,313. Last year, at this time, 13 human cases of West Nile had been confirmed.