PHONE
800-231-3236 (toll free)
707-285-2200 (office)
707-285-2210 (fax)
ADDRESS
595 Helman Lane
Cotati, California
94931-9736
HOURS
Monday through Friday
7:00AM to 3:30PM
Defend yourself against mosquitoes by using an effective insect repellent, such as DEET, Picaridin or Oil of Lemon Eucalyptus. Make sure you follow all label directions!
West Nile virus first appeared in the Americas in New York City in 1999, with 62 human cases. It is mainly a devastating disease of birds. In just four years, migrating wild birds carried the virus all the way across the U.S., Canada, Mexico and the Caribbean. Weekly maps from the CDC (see below) traced the spread of animal and human infections across the U.S.
California's public health agencies began preparing in 1999 to confront West Nile virus' arrival. Mosquito control districts across the state worked tirelessly to reduce the numbers of potential vectors around towns and cities. As a result, when the first wave of infection hit in 2004, Californians saw infection rates four times lower than Arizona, and 44 times lower than Colorado during its epidemic the year before (Colorado did not have an organized mosquito control program at the time).
MSMVCD personnel maintain a constantly updated database of every known breeding source for pest and vector mosquitoes. These efforts are geared toward keeping the density of mosquitoes capable of carrying the virus in populated areas below levels that could support an epidemic.
The Center for Disease Control confirmed California's first case in early September 2002. Infected birds, mosquitoes, and two human cases were reported in southern California in 2003. With the next spring migration, the virus traveled north. By late September, 3,232 infected wild birds had been submitted to the Department of Health Services by residents from all 58 counties. That year, there were 830 confirmed human infections, with 28 deaths. 2005 records showed 880 Californians with infections severe enough to require medical attention, and 19 deaths. In 2006 the number had dropped to 278 infections severe enough to require medical attention and 7 deaths. There was an increase in 2007 to 378 infections and 18 deaths.
Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all. Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks. About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
The West Nile virus epidemic in the U.S. typically reaches its annual peak in late August or September. Most infections cause mild or low-grade symptoms, and are never diagnosed. Researchers estimate that perhaps one in 100 cases produce symptoms severe enough to require a doctors visit or hospitalization. More than 1.5 million people may have contracted WNV infections in the United States during 2003.
Culex pipiens (the "house mosquito") feeds on both birds and mammals. It is the species most likely to transmit infection to residents of Marin and Sonoma Counties, but at least 43 other mosquito species are known to carry the virus. Culex tarsalis (the "encephalitis mosquito") is another important local vector.
West Nile virus impact on wildlife populations
West Nile virus develops in a unusually wide variety of New World birds, reptiles, mammals and mosquitoes. Infections have been discovered in at least 232 different species of native wild birds. For example, during 2003 it was shown to have killed 11,350 of the crows, blue jays, finches, sparrows and other birds sent for testing from 43 states. Monitoring the deaths of wild corvids and similar birds helps reveal the intensity of local infection. The California Department of Public Health arranges to collect the carcass from the location it was found if WNV testing is indicated.
West Nile infection is especially serious in horses, and approximately 40% will die if not vaccinated. During 2006, California veterinarians reported 508 infections in horses.
Vaccination Recommendations for West Nile Virus in Horses
Univ. Calif. Davis - Center for Equine Health
2008 Marin/Sonoma West Nile Virus Collection Data
M/S MVCD database
West Nile Virus Adult Mosquito Control Maps
Adult Mosquito Control Maps
What do I do if I find a dead bird?
Please contact the DHS at the number below:
West Nile Virus Dead Bird Surveillance Program
Division of Communicable Disease Control
California Department of Health Services
Telephone: 877-WNV-BIRD (877-968-2473), or
you can submit a form online.
WNV Dead Bird Hotline: (877) WNV - BIRD or (877) 968-2473
West Nile Virus Activity in the United States
2007 West Nile Virus Activity in the United States
(Reported to CDC as of February 5, 2008)
Helpful online resources:
- California's website for West Nile Virus
- California's Vectorborne Disease Surveillance System
- CDC's West Nile Virus Home Page
- CDC's Questions and Answers about Vest Nile Virus
- UC Davis Vector Borne disease information Page
- APHIS Equine WNV surveillance Page
- Wild Birds & WNV
- Pesticide information
- Marin County Health and Human Services
- Sonoma County Department of Health Services
The U. S. Geological Survey monitors every United States county where laboratory-confirmed West Nile virus cases occur.
YOU CAN PREVENT MOSQUITO BREEDING
EMPTY OR COVER CONTAINERS THAT CAN HOLD WATER
PUT MOSQUITO FISH IN PERMANENT PONDS
STORE OLD TIRES INSIDE OR COVER