First Human Case of West Nile Virus in Marin County in 2013

Release date: 
Aug 16

Cotati, CA -The Marin/Sonoma Mosquito and Vector Control District (MSMVCD) received confirmation from Marin County Public Health Officials of the county's first human case of West Nile virus (WNV) in 2013.


MSMVCD officials are urging residents to take West Nile virus seriously and take precautions when engaging in outdoor activities, especially during dusk and dawn when mosquito activity is at its peak.


"Using a repellent that has been proven to be effective is essential to protect against disease carrying insects," stated Nizza Sequeira, Public Relations Director for the Marin/Sonoma Mosquito and Vector Control District. "The most effective repellents contain DEET, picaridin, oil of lemon eucalyptus (PMD) or IR3535," said Sequeira. 


As a part of MSMVCD's integrated vector management program, mosquito populations are closely monitored with control strategies implemented as necessary. Additional surveillance methods are being employed in areas where recent virus activity has been detected. MSMVCD officials are asking that residents report mosquito problems to the district immediately.    


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

  • Eliminate standing water in rain barrels, old tires, buckets, kiddie pools or any other item that can hold water for more than 72-96 hours. 
  • Check septic tank lids to ensure a tight seal and repair any visible cracks.
  • Screen septic tank vent pipes using a fine mesh screen.
  • Report mosquito problems, neglected swimming pools, or any area that could be producing mosquitoes at or 1-800-231-3236.
  • 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 or online at
  • 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. 
  • Residents interested in staying informed about district activities are encouraged to follow MSMVCD on twitter and facebook.

West Nile virus 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. For recent WNV activity in Marin and Sonoma counties click here.


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.