452 West Nile Cases Reported Statewide

California reported 452 human cases of West Nile virus as of October 23, a substantial increase from the 67 cases recorded across the state at the same point in 2025.

Of those statewide cases, 251 occurred in Los Angeles County, which encompasses the city of Pasadena. State health officials also reported 29 deaths associated with the virus throughout the 24 affected counties. In contrast, only 15 counties reported human infections during the same period last year.

On Thursday, the Pasadena Public Health Department announced the city's first two human cases for this year. Both patients met the necessary clinical and initial laboratory criteria for diagnosis. However, officials noted that additional testing is currently pending to fully confirm the infections. The city had reported a last confirmed human case in 2025, marking a gap of nearly one year before these new reports.

Dr. Parveen Kaur, the Pasadena Health Officer, explained that the virus spreads through bites from infected mosquitoes. She stated that there is currently no vaccine or cure for West Nile virus disease. While most infected individuals experience no symptoms, some develop a potentially life-threatening condition. Kaur emphasized that prevention remains the primary defense against the illness.

Public Health Director Manuel Carmona urged residents to take an active role in reducing the threat of the virus. In a statement, Carmona said, "The most effective way to protect yourself is by preventing mosquito bites." He encouraged the community to follow specific mosquito prevention tips to lower their risk of exposure.

Health officials recommend that homeowners empty standing water around their properties weekly and discard unused containers that collect rainwater. Residents should also repair window screens to keep mosquitoes out. When outdoors, individuals are advised to wear protective clothing and apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or IR3535.

The Pasadena Public Health Department is currently working with the San Gabriel Valley Mosquito and Vector Control District. The two agencies are monitoring local mosquito activity and conducting inspections and treatments in public spaces to manage the vector population.