ROSEVILLE, Calif. — Placer County’s health officer, along with the Placer Mosquito and Vector Control District, continue to encourage residents to take preventative steps that will reduce their risk of acquiring mosquito-borne illnesses. Since the first 2025 detection of West Nile virus in Placer County in June, the District has detected the virus in 5 dead birds and in 129 mosquito samples. The county’s first human case of West Nile virus in 2025 was reported in a Lincoln resident this week.

West Nile virus is a potentially serious illness transmitted through the bite of a female mosquito and there is no cure. “Many people infected with West Nile virus don’t even realize it or only feel mild effects,” said Dr. Rob Oldham, the county’s health officer. “But for a small number — about 1 in

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