September 8, 2004


---Disease Surveillance Working----


STOCKTON, CA San Joaquin County Mosquito and Vector Control District has received notification from the California Department of Health Services that West Nile Virus has been detected in one of the District’s six flocks of sentinel chickens.  The flock, located on Roberts Island, is the first flock of chickens to show positive for WNV in San Joaquin County. 


Blood samples are taken from each chicken biweekly and checked for the presence of antibodies to mosquito borne viruses.  In addition to checking the sentinel chicken flocks, the district also tests for West Nile virus in dead birds; to date there have been 16 positive dead birds confirmed in San Joaquin County this year. “The new find confirms that our surveillance and testing procedures are working”, said John Stroh, Manager of the San Joaquin County Mosquito and Vector Control District.  “The District will perform additional surveillance and mosquito control operations to combat West Nile Virus.” Although no West Nile virus has been found in trapped mosquitoes within San Joaquin County, local mosquito breeding sites will be targeted for treatments using public health pesticides, mosquito-eating fish, and legal enforcement where necessary.


“The proximity of the chicken flock where the virus was detected to mosquito-breeding sites such as irrigated agriculture fields, managed wetlands, and other aquatic sites is especially serious,” said Stroh.  “Detecting virus in a region where there is the potential for high mosquito populations combined with extensive sites with standing water is of great concern.”    


 It is now more important than ever that individuals take precaution to reduce their exposure to mosquitoes. The public is asked to help by reducing any standing water on their property. The virus is spread by mosquitoes, which feed on the blood of infected birds and can then pass it on to humans or other mammals.


Individuals can reduce their risk of mosquito-borne diseases by taking these precautions:






WEST NILE VIRUS FOUND IN SENTINEL CHICKEN FLOCK                                  Page 2




  For information about WNV, visit the Web sites: www.sjgov/oes, or  For additional contact numbers and local recorded information call 209-469-8200. 


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