Kern County • 1031 S. Mt. Vernon Avenue • Bakersfield, CA 93307 • 661-868-6200

December 15, 2003 Ralph Phillips, Farm Advisor

Range/Natural Resources and Livestock

WEST NILE VIRUS

West Nile Virus, (WNv) is a disease that is transmitted by adult female mosquitoes. The disease was first observed in New York in 1999 and by the end of 2002, all but four states (Oregon, Nevada, Utah and Arizona), have reported cases of WNv. A total of 3,389 cases were reported in 2002. Humans and horses are accidental hosts for WNv.

Most people who are infected with WNv have no symptoms. However of those who become ill, symptoms can include fever, headache, nausea, body aches and mild skin rash. In a few cases, it progress to an inflammation of the brain that could lead to death. The death rate is about ten percent for the people who become infected.

The chances of dying from WNv are not very great, but not one wants to be in the small percentage that dies. Pregnant women with WNv can give birth to a child with the disease.

Birds are the most sensitive to the virus, especially crows, jays, magpies and ravens. Other bird species can carry the virus but appear not to be affected. However, these species can act as a receiver for WNv. California has a dead bird surveillance program. If a dead bird is found, do not touch it, but contact the West Nile Virus Dead Bird Surveillance program at their toll free number, 877-968-2473.

The disease cannot be transmitted from human to human or animal to human, only through the bite of a mosquito. At this time, there is not a vaccine for humans and although a vaccine for horses exists, there is some controversy regarding its use.

Presently, the best practice is to control mosquitoes and protect yourself from being bitten by them. Although the mosquito season is slowing down there are some actions you need to keep in mind to prepare for the next mosquito season.

Kern County has a very active mosquito abatement program. This program does a good job of controlling mosquitoes in a large area where most mosquitoes breed. However, individuals can control mosquitoes around their homes and properties by making sure there is no standing water on the property. Old tires, tin cans and plastic jugs are good breeding places for mosquitoes. Mosquitoes can complete a life cycle from laying eggs to hatching out adults in as few as seven days.

Over watering your yard could provide an excellent breeding site for mosquitoes. Also, poorly maintained swimming pools and decorative fountains are good breeding sites. If you have a livestock water through and/or pond, contact Kern Mosquito Abatement at 589-2744 to obtain mosquito fish. These fish feed on mosquito larvae and do an excellent job of control.

You can protect yourself from mosquito bites by taking the following precautions:

· Avoid outside activity at dawn and dusk when mosquitoes are most active.

· Wear protective clothing (long pants and long sleeves) and apply insect repellant when outside.

· Make sure that doors and windows have tight-fitting screens.

More information is available at the following websites:

West Nile Virus Facts: http://www.westnilevirusfacts.org/

California Animal Health and Safety (CAHFS): http://cahfs.ucdavis.edu/

Centers for Disease Control and Prevention: http://www.cdc.gov

California Department of Health Services: http://www.dhs.ca.gov