ROSEVILLE, Calif. – Mosquito samples in residential areas of west and northwest Roseville are turning up positive for West Nile virus.

“Although the actual numbers of mosquitoes are low, infection rates among mosquitoes are high,” statedJoel Buettner, General Manager of the Placer Mosquito and Vector Control District. The District is concerned that this increases the risk for transmission of the virus to humans, since West Nile virus is now being found in areas with higher human population densities.

“In general, when we find disease, we increase surveillance by trapping adult mosquitoes and identifying additional breeding sources. When virus activity increases, we treat the affected area to control for both larval and adult mosquitoes,” adds Buettner.

Due to this latest development, the District has scheduled a ground-based adulticide application for the early morning of August 14 in the following areas of Roseville:

  • Blue Oaks Park and surrounding area:

South of Blue Oaks Blvd to Marblethorpe Drive, east of Sierra Pines Golf Course to Woodcreek Oaks Blvd and to the north edge of Woodcreek Golf Course.

  • Morgan Creek Golf Course and surrounding area:

South of Vineyard Road to PFE Road, between Walerga Road and Cook Riolo Road

Since several factors affect spraying activities, such as weather and wind conditions, the District encourages Placer residents to check the District website at for any changes to the spraying schedule.

With West Nile virus spreading to more populated areas of the county, the Placer Mosquito and Vector Control District 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, 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, or to report potential mosquito breeding sources, such as neglected swimming pools.

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

2010 Placer County West Nile virus activity update:
3 dead birds, O sentinel chickens, 18 mosquito samples have tested positive for West Nile Virus to date.

Contact: Ada Barros, Public Information Officer (916) 380-5480.