West Nile Virus Activity Confirmed in Local Mosquito Populations

Release date: 
Sep 22

Cotati, CA - The Marin/Sonoma Mosquito & Vector Control District (District) received confirmation today that another mosquito sample has tested positive for West Nile virus from the Ellis Creek Water Recycling Facility in Petaluma.

“As indicated by the detection of the virus in this mosquito sample, West Nile virus season is not over yet in Marin and Sonoma counties,” said Nizza Sequeira, Public Relations Director for the Marin/Sonoma Mosquito & Vector Control District. “With warm daily temperatures remaining in the forecast, there is potential for an increase in West Nile virus activity,” said Sequeira.

Weather patterns play a substantial role in the mosquito-borne disease transmission cycle. Increases in daily temperatures can contribute to an increase in mosquito-borne disease transmission in two ways: the mosquito life-cycle and the rate of viral amplification within the mosquito itself are accelerated.

The District will continue to monitor the area for additional virus activity and mosquito populations and conduct mosquito control on an as needed basis.

With West Nile virus activity increasing in other parts of California, District officials recommend residents keep abreast of virus activity when traveling to other parts of the state. To date there have been 199 human cases of West Nile virus from 24 counties within California. More information about West Nile virus in California can be found at www.westnile.ca.gov.

2016 West Nile Virus Activity 

Sonoma County: 7 dead birds and 2 mosquito pools (sample)

Marin County: 5 dead birds

Simple ways to help reduce exposure to mosquitoes and lessen the risk of WNV:

  • Contact the Marin/Sonoma Mosquito & Vector Control District (707-285-2200) if you have a mosquito-related problem that you cannot resolve on your own. 
  • Check and maintain all window and door screens.
  • Continue to report dead birds to the West Nile virus hotline at 1-877-WNV-BIRD or online.
  • Wear mosquito repellent when outdoors at dusk and dawn. Use a repellent containing one of the following active ingredients: DEET, Picaridin, oil of lemon eucalyptus, or IR3535. 
  • Avoid being outdoors during peak mosquito activity (dawn and dusk).
  • Click here for our Backyard Checklist to help identify areas around your home that may produce mosquitoes.