June 15, 2017 – West Nile Virus (WNV) was recently detected in a dead bird from Grass Valley. This is the first confirmation of WNV in the county this year. As of June 9, 2017, 13 counties in California have reported WNV activity mainly in dead birds and mosquito samples; there has been only one human case reported in California so far this season.

Stagnant water left behind from the heavy winter rains make good breeding grounds for mosquitoes, so it is important to eliminate any sources of pooling or collecting water around homes.

For most people, the risk of serious illness is low; however, some people (less than one percent) can develop a serious neurologic illness such as meningitis or encephalitis (i.e., brain inflammation). People 50 years of age or older have the greatest risk of complications.

To reduce the risk of being infected, residents are encouraged to:

  • Remain indoors at dawn and dusk when mosquitoes are most active, or
  • Wear long sleeves and pants during dusk and dawn;
  • Defend yourself by using an effective insect repellent and following the label directions;
  • Remove water standing for more than 3 days from bird baths, pet dishes, flower pots, outdoor stored automotive tires or neglected swimming pools; and
  • Keep door and window screens in good working condition.

California’s WNV website (http://www.westnile.ca.gov/) includes the latest information on WNV activity in the state. Californians are encouraged to report all dead birds through the website. Dead birds can also be reported by calling toll-free 1-877-WNV-BIRD (968-2473).

Of note, Zika virus is typically carried by a different mosquito than WNV, and that mosquito has not been found in Nevada County. Zika virus is associated with birth defects, so travelers, particularly those who are pregnant or planning to be parents, should consult with their physicians prior to travel to countries with Zika transmission.

Additional information for contacting Nevada County Vector Control can be found at: http://www.mynevadacounty.com/nc/cda/eh/Pages/Vector-Program.aspx