Veterinary Public Health

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Contact Information
Veterinary Public Health Program
313 N Figueroa St. Rm 1127
Los Angeles, CA 90012
Tel (213) 989-7060
Fax (213) 481-2375
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West Nile Virus 2009

2009 Los Angeles County West Nile Virus Map - dead birds

NEW - Movie Maps!
WNV-positive birds in 2009 through Aug18
(.wmv file, 1.2 MB)
WNV-positive birds in 2008 (.wmv file, 1.7 MB)

West Nile Virus (WNV) is transmitted to humans, horses, and birds by the bites of infected mosquitoes. Testing dead wild birds for WNV provides a way tracking the virus in our environment. Veterinary Public Health works with the California Department of Public Health and local mosquito control agencies in conducting WNV surveillance in Los Angeles County.  

To report a dead bird in Los Angeles County, click here
To read more about WNV in humans, click here.

Weekly WNV Map
Updated 12.2.09

Starting 10.8 and continuing until approximately March 2010, the state's West Nile Virus testing program  (which conducts most WNV tests for LA County Public Health) discontinued testing dead birds for the winter.  However, LA County Public Health is able to test individual CROWS for WNV during this time.  LA Public County Health can also conduct tests in cases where there is a die-off of three of more birds.

As always, thanks to Los Angeles County residents, Animal Control Agencies, and vector Control Agencies for you assistance with WNV surveillance.





Graphing WNV
Updated 1.19.10 
The number of birds tested varies by month and by year.
By monitoring the percentage of tested birds that were positive, we have a way of comparing years. Graph - Dead birds with West Nile Virus Los Angeles County 2004 - 2009

2003: West Nile Virus first arrived in Los Angeles County late in the year (not shown)
2004: This was one of the most severe WNV seasons. The percentage of WNV-positive birds increased dramatically in April, and peaked In August, with 88% of dead birds collected being WNV-positive.
2005, 2006, 2007: These three years were much milder in terms of WNV than 2004 and settled into a consist pattern. The season appeared to start in June each year, and peaked in August with 55% of tested birds being positive.
2008: A dramatic increase in WNV was seen, with the season beginning in May and peaking in August with 77% of dead birds testing positive. The reasons for this resurgence of WNV are not known. One theory is that an increase in neglected swimming pools, caused by the financial crisis, may have been a large contributor.
2009: The WNV season was milder than in 2008.






Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.
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