Pasadena Public Health Reports Two West Nile Virus Cases and Urges Mosquito Bite Prevention

PASADENA, Calif.- The Pasadena Public Health Department (PPHD) reports the first two human cases of West Nile virus (WNV) in Pasadena for 2026 on October 29 and urges residents to take precautions against mosquito bites. These cases meet clinical and initial laboratory criteria for WNV, but PPHD is awaiting the results of confirmation testing.

As of October 23, 2026, California had reported 452 human cases of WNV disease and 29 deaths across 24 counties, including 251 cases in Los Angeles County, according to the California Department of Public Health (CDPH). At the same time last year, 67 human cases were reported across 15 California counties.

WNV is most often detected during warmer months when mosquitoes are breeding and can quickly spread viruses. PPHD continues to monitor disease activity and collaborate with the San Gabriel Valley Mosquito and Vector Control District to control mosquitoes in public spaces through routine inspections and necessary treatments. The last confirmed case of WNV in a Pasadena resident was in 2025.

"WNV spreads to people through the bite of an infected mosquito," said Dr. Parveen Kaur, Health Officer. "Most people infected with the virus do not develop symptoms. However, a small percentage can develop a potentially life-threatening illness. There is no vaccine or cure for West Nile virus disease."

"The most effective way to protect yourself is by preventing mosquito bites," said Manuel Carmona, Director of Public Health. "PPHD urges residents to take an active role in reducing the threat of West Nile virus by following mosquito prevention tips."

Take the following actions to reduce the presence of mosquitoes, stay healthy, and bite-free:

• Tip out stagnant water around the home weekly;
• Toss unused containers that can hold stagnant water;
• Use screens on windows and fix holes in screens; and
• Protect against bites by wearing protective clothing and using insect repellent containing any one of the following recommended ingredients: Picaridin, DEET, Oil of Lemon Eucalyptus (or PMD), or IR3535.

Help track West Nile virus activity

Birds can carry WNV, and some birds can get very sick and die from it. Reporting dead birds can help track where the virus is spreading. Help track WNV activity by reporting dead birds at the California West Nile Virus website or by calling 1-877-WNV-BIRD (968-2473).

For more information about West Nile virus, prevention, and surveillance, visit the California Department of Public Health's West Nile Virus webpage.