Placer County Mosquito & Vector Control warns of West Nile detections; urges source reduction

Megan Lovano, public information officer for the Placer County Mosquito and Vector Control District, briefed the Loomis Town Council on seasonal mosquito conditions and public-health precautions.

Lovano said the district detected West Nile virus in the West Park neighborhood of Roseville on June 21 and has recorded three positive dead birds and 14 positive mosquito samples in Placer County to date. She said the district expects to see more virus activity through August and is making treatment decisions based on trap results.

The district also reported early detections of invasive Aedes mosquitoes (first detected in the county on June 13). Aedes species can carry pathogens such as Zika, dengue and chikungunya if those pathogens are introduced into the area; Lovano said the county has no current human cases of those diseases but asked residents to be vigilant because the mosquitoes breed in very small amounts of standing water.

The district highlighted its mosquito fish program (free placement of fish in ponds and horse troughs), recommended use of EPA-registered repellents such as DEET and picaridin, and urged residents to drain even small containers of water. Residents can sign up for treatment updates and see treatment locations on the district website.

The district also noted that record rainfall and late snowmelt may increase mosquito numbers in some parts of the county.

Next steps: The district will continue surveillance and targeted treatments; residents should remove standing water and register for updates.