Two More Dead Birds Test Positive for West Nile Virus in Sonoma County

Release date: 
Oct 2

Cotati, CA - The Marin/Sonoma Mosquito and Vector Control District (District) confirmed finding two dead birds infected with West Nile virus (WNV) in Santa Rosa, CA. The birds were both American crows and lab tests showed that they were recently infected with the virus. One bird was found in the vicinity of Occidental Road and Irwin Lane and the other in northwest Santa Rosa near Barnes Road and Dennis Lane.

"Continued high temperatures are an important factor in the proliferation of West Nile virus in the area," said Erik Hawk, Assistant Manager of the Marin/Sonoma Mosquito and Vector Control District.

The presence of West Nile virus is high this year in many areas of California, especially in areas where temperatures are high. Standing water coupled with high temperatures creates an ideal situation for rapid mosquito production and elevated levels of the virus within the mosquito, making transmission to humans, birds and animals more likely.

"Technicians are now setting mosquito traps in the vicinity of the dead birds to assess the abundance and species of mosquitoes and to evaluate whether or not they are carrying the virus. All known mosquito breeding sources are being monitored, and technicians are combing the area in search of other sites that may be producing mosquitoes." stated Hawk.

The District works diligently year-round to protect residents from mosquitoes and vector-borne disease. During the summer months additional staff is hired to meet the increase in demand for our services, in a service area which spans over 2000 square miles.

The most difficult issue the District faces is dealing with the mosquito breeding sites found in residents' backyards. Common mosquito production sites include ponds, bird baths, septic tanks and even rain-harvesting barrels that haven't been screened correctly. Foreclosed homes with neglected swimming pools pose another risk, as they can produce large populations of mosquitoes. Residents are urged to report mosquito problems, neglected pools, or any area they suspect may be producing mosquitoes to the District at 1-800-231-3236.

Residents can help reduce the threat of WNV in the following ways:

  • Eliminate standing water in rain barrels, old tires, buckets, kiddie pools or any other item that can hold water for more than a week.
  • Report mosquito problems, neglected swimming pools, or any area that could be producing mosquitoes.
  • Stock backyard ponds or other permanent water features with mosquitofish. The fish are free and can be delivered or simply picked up at the District office.
  • Report dead birds to the West Nile virus hotline at 1-877-968-2473.
  • 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.

West Nile virus (WNV) is a mosquito-borne disease that is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread the disease to humans and other animals.

Less than 1% of people (1 in 150) infected with WNV develop serious illness. These cases may last for extended periods of time, result in permanent neurological damage and may be fatal. Approximately 20% of people (about 1 in 5) infected with WNV experience mild symptoms that may include fever, headache, body aches, nausea, rashes, swollen lymph nodes and vomiting. Approximately 80% of people (about 4 out of 5) infected with WNV do not show any symptoms.

For more information or to report mosquito problems contact the Marin/Sonoma Mosquito and Vector Control District at 1.800.231.3236 or visit

Report dead birds to the West Nile virus Hotline at 1-877-968-2473 or online at

The Marin/Sonoma Mosquito and Vector Control District is an independent, special district committed to protecting public health from mosquitoes and mosquito-borne diseases. All programs and services are funded through property taxes and are provided to all residents of Marin and Sonoma counties. For more information about us please visit our website at or call 1-800-231-3236.