Hermosa Beach, Hawthorne and Redondo Beach are among 11 South Bay cities where residents have contracted West Nile virus in 2026, as Los Angeles County reports a 10-year high in infections, the Daily Breeze first reported.

The county has confirmed 216 cases, up from 22 in all of 2025. The South Bay accounts for roughly 25% of those infections, and nearly all of the local cases have progressed into neuroinvasive disease, a severe form that can cause brain swelling, paralysis and death, according to the county Department of Public Health.

Ten people have died countywide, according to the department's most recent report.

Susanne Kluh, general manager of the Greater Los Angeles Vector Control District, told the Daily Breeze that coastal cities have historically seen little West Nile activity because cooler overnight temperatures keep mosquito populations low. This year broke the pattern. Kluh pointed to the warmest winter on record, saying the virus "has gone all the way to the coast."

There is no vaccine and no specific treatment for West Nile virus. About 80% of people who contract it show no symptoms, according to the Centers for Disease Control and Prevention. The virus spreads through mosquito bites, primarily from female culex mosquitoes active from about May through November.

Kaiser Permanente South Bay Medical Center has treated 25 West Nile patients in 2026 after recording zero confirmed cases in each of the previous two years, the Daily Breeze reported, citing the hospital's chief of infectious diseases, Gunter Rieg.

Los Angeles County Health Officer Muntu Davis urged residents to act now, saying in a written statement that the county remains in the peak transmission period. Health officials recommend:

  • Using insect repellent on exposed skin
  • Wearing long sleeves and pants outdoors
  • Eliminating standing water where mosquitoes breed
  • Checking window and door screens for holes or tears

Rieg advised residents to seek hospital care if they develop fever, headache, body aches or a rash after a mosquito bite, especially if symptoms worsen into severe headaches, a stiff neck, confusion or muscle weakness.

Residents can find mosquito activity maps and prevention resources at westnile.ca.gov.