San Bernardino County is experiencing a marked increase in West Nile Virus activity this season, according to the Department of Public Health.
As of August 6, 2026, the county has detected several positive West Nile Virus mosquito pools and numerous infected dead birds—representing a significant increase compared to August 2025 and August 2024. The department is continuing to monitor for human cases.
Health officials are urging residents to take steps to prevent mosquito bites and practice mosquito control at home and in their communities. The warning comes as rising temperatures and changes in rainfall and bird populations create conditions favorable to mosquitoes.