Stanislaus County confirms 1st human case of West Nile Virus in 2026

Stanislaus County has reported its first human case of West Nile virus for 2026 as the number of cases in California surges compared to recent years.

The county's Health Services Agency said in a press release on Monday that the last significant increase in human West Nile vires cases was in 2023. WNV activity in California is currently at a five-year-high, according to the state Department of Public Health.

Stanislaus County did not specify where the virus was detected. Public Health Officer Dr. Thea Papasozomenos urged residents to protect themselves and their families from mosquito bites, noting that there is no vaccine or treatment for West Nile virus.

"Current surveillance indicators signal a severe West Nile virus season for 2026 with concern for a higher number of human cases," Papasozomenos said.

There have been 46 reported cases of West Nile virus in California this year, including four fatalities, compared to 14 cases at this point last year. The deaths have occurred in Butte, Fresno, Glenn, and Kings counties. According to health officials, the number of human cases typically peaks during August to September.

West Nile virus is transmitted to people and animals by infected mosquitos. Most people who catch the virus don't show any obvious symptoms and often won't realize they have it, health officials say. Others may experience fever, headache, and tiredness. In rare cases, the virus can cause serious illnesses that affect the brain and spinal cord, such as encephalitis or meningitis, which could lead to long-term problems or death, with older adults and those with weakened immune systems are particularly susceptible.

About one out of five people infected with West Nile virus develop symptoms such as fever, headache, body aches, joint pain, vomiting, or rash. Fewer than 1% of the estimated 2,000 people diagnosed with West Nile virus develop severe neurological illnesses such as encephalitis or meningitis, and about 130 people die each year from the virus, according to the U.S. Centers for Disease Control and Prevention.    

Residents are urged to use an EPA-registered insect-repellant and apply it when spending time outdoors, especially during the peak mosquito hours of dawn and dusk. People are also encouraged to dump and drain standing water regularly where mosquitoes breed.

In Stanislaus County, residents who notice an unusual number of mosquitoes or mosquitoes that bite during the day are asked to contact either the East Side Mosquito Abatement District at 209-522-4098 or the Turlock Mosquito Abatement District at 209-634-1234.

Dead birds can be a warning sign of West Nile virus in your area, and should be reported to the California West Nile Virus Dead Bird Hotline at 877-968-2473 or westnile.ca.gov.