ROSEVILLE, Calif., February 9, 2012 – The Placer Mosquito and Vector Control District reports an increase in calls from Placer County residents, especially on the western border, where mosquito activity has increased in the past few weeks. “Mosquitoes are certainly noticeable right now, but the good news is, the risk of disease is very low,” assures Joel Buettner, General Manager for the District.

According to the District, mosquitoes that emerge during warm spells during the winter are not the species known to be effective in transmitting West Nile virus. In the fall, these mosquitoes seek shelter in protected places such as attics, outbuildings, covered patios, and shaded doorways where they hibernate over the colder winter months. They emerge on warmer winter days, and if daytime temperatures drop, they are likely to return to their overwintering shelters.

“Adult mosquito control methods during the summer months are not as appropriate or effective during the winter because of the weather and mosquito behavior during this time of year,” states Buettner. To best limit the impact of winter mosquitoes, the District strongly recommends the following:

  • Use an effective mosquito repellent
  • Limit outdoor activity at dawn and dusk
  • Keep doors closed and window screens in good repair

The Placer Mosquito and Vector Control District is aware of the current winter mosquito issues, and is constantly working to improve prevention and public education methods to address this seasonal problem. For more information, contact the Placer Mosquito and Vector Control District at (888) 768-2343 or visit