Los Angeles County has recorded 135 West Nile virus infections and five deaths this year, according to the county Department of Public Health's arbovirus report, with data through Sept. 24. The county said the number of people infected this season is greater than its five-year average for the same period.
The jump is steep. In all of 2025, the county documented 22 infections and two deaths. Earlier this month, the county described its count as the highest number of West Nile cases in nearly a decade. For a county of nearly 9.7 million people, the numbers remain small, but the share of serious illness among reported cases is high, and mosquito activity typically continues into October.
