Mosquitoes Test Positive For West Nile Virus In Sonoma County

Release date: 
Aug 3

Cotati, CA - The Marin/Sonoma Mosquito & Vector Control District announced today that 2 (two) groups of mosquitoes have tested positive for West Nile virus. The infected mosquitoes were trapped near Wilfred Avenue in Rohnert Park.


"Technicians are out in force, checking known mosquito sources and searching for anything else that may be producing mosquitoes." said Nizza Sequeira, Public Relations Director for the District. "We have set additional adult mosquito surveillance traps to monitor the abundance of mosquitoes as well as additional virus activity," stated Sequeira.


Sequeira urges residents to check their yards for standing water and to report suspected mosquito sources and mosquito problems to the District. Neglected swimming pools, discarded tires, ponds, water features, septic tanks, watering troughs and even plant saucers are common areas mosquitoes can be found reproducing.


"The faster we can determine the source of mosquito production, the faster we can reduce the risk of West Nile virus and protect the public's health," Sequeira added.


Residents are urged to take personal protection measures such as applying an effective mosquito repellent to exposed skin when outdoors, especially during dusk and dawn.


West Nile virus symptoms may include headache, fever, body aches, vomiting, nausea, swollen lymph glands and skin rash on the chest, stomach and back.


Approximately 80% of people who become infected with WNv will not show any symptoms; approximately 20% of infected individuals, however will develop West Nile fever.


Less than 1% of those individuals may develop a more severe form of illness with symptoms such as high fever, headache, neck stiffness, disorientation, coma, paralysis and in extreme cases death. While there is no cure for WNv, it is preventable.  


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 during dusk and dawn. Use a repellent containing one of the following active ingredients: DEET, Picaridin, oil of lemon eucalyptus, or IR3535.

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.