ROSEVILLE, Calif. July 5, 2012— The Placer Mosquito and Vector control District reports that mosquito samples taken from surveillance traps in Roseville and Loomis in Placer County have tested positive for West Nile virus.  This is the first indicator of increasing West Nile virus activity for the season.

Last year, the first WNV-positive samples did not come until the last week in July. “This finding is certainly in line with what mosquito control districts are experiencing throughout the state this year.  We saw an early start to the mosquito season, and very early indicators of increased West Nile virus activity,” stated Joel Buettner, General Manager of the Placer Mosquito and Vector Control District.  Public health experts are concerned that weather conditions and new challenges to mosquito control resources this year may result in a longer and more intense West Nile virus season.  “Every year, we strive to stay ahead of mosquito and West Nile virus issues. This year has the potential of being a very challenging one, and we may have to work twice as hard just to keep up,” Buettner adds.

Due to this latest development, the District has increased surveillance of larval and adult mosquitoes in the area and treatments for adult and larval mosquitoes are already underway in the affected areas.

Vector control experts urge residents of Placer County to be aware that West Nile virus is a threat, especially with high levels of virus activity in the surrounding counties of Sacramento and Sutter.  Placer County residents can defend themselves against mosquitoes by wearing an effective insect repellent and staying inside, behind screened windows and doors, whenever possible.

The Placer Mosquito and Vector Control advises the public to implement the 3 Ds of protection:

  • Drain any standing water that may produce mosquitoes.
  • Defend yourself and your home by using an effective insect repellent and dressing protectively when outside, and making sure screens on doors and windows are in good condition.
  • Contact the District for any additional help controlling mosquitoes around your home.

For more information, contact the Placer Mosquito and Vector Control District at (888) 768-2343 or

2012 Placer County West Nile virus activity update: 0 dead birds, 0 sentinel chickens, 3 mosquito samples, and 0 humans have tested positive for West Nile Virus to date