The Placer Mosquito and Vector control District reports that mosquito samples taken from surveillance traps in Roseville and Sheridan Placer County have tested positive for West Nile virus.  These are the first mosquito samples turning positive for the 2013 season.

Public health officials are concerned that late spring rainstorms may have created more areas where mosquitoes can lay their eggs. “The most recent rain, followed by the very high temperatures in the next few days create ideal conditions for a surge in the mosquito population,” stated Joel Buettner, General Manager of the Placer Mosquito and Vector Control District.  With West Nile virus activity increasing, and a potential increase in mosquito populations, the District is encouraging the public to be proactive in preventing mosquito-transmitted diseases. “Eliminating any potential mosquito sources and using CDC-recommended repellents will help minimize individual risk for West Nile virus,” Buettner explains.

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

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

2013 Placer County West Nile virus activity update: 2 dead birds, 0 sentinel chickens, 4 mosquito samples, and 0 humans have tested positive for West Nile Virus to date