The Bay Area’s first death resulting from the West Nile virus is not alarming San Francisco health officials.
An elderly woman, who lived in the central part of Contra Cost County, died "some days ago" as a result of the mosquito-borne West Nile virus, Wendel Brunner, the county’s public health director, announced Thursday morning. The woman is the second to die of the virus this year in California.
While this recent West Nile-related death occurred near San Francisco, there is no reason to believe people in The City are more at risk for contracting the disease, according to city officials.
Contra Costa County has a "very different climate than we’re dealing with here," San Francisco’s Senior Health Inspector Helen Zverina said. San Francisco’s cool nights make it difficult for the virus to spread, she said, adding that the virus needs temperatures to be at least 60 degrees overnight.
To determine if West Nile is a threat to residents, The City’s Department of Public Health tests dead birds. The virus is often spread among birds by mosquitoes.
So far this year, none of the 50 dead birds tested by the DPW have been infected with West Nile. Of the 60 dead birds examined last year, three tested positive.
Health officials will remain vigilant, as the mosquito season peaks in September.
To cut down on mosquitoes in San Francisco, the San Francisco Public Utilities Commission has implemented a $1.5 million program this year that kills mosquitoes in The City’s 20,000 water catch basins, or sewers.
Every month, bike messengers are given a capsule of larvicide, an oily chemical that kills mosquito larvae, to drop into every city sewer. The sewers are considered The City’s largest source for mosquito breeding.
The state’s first West Nile-related death this year occurred on Aug. 17, when an elderly Butte County woman died after contracting it. The elderly are more likely to die of the disease.
Since 1999, 49 deaths due to West Nile have been documented in California. Symptoms of the disease include a fever, headache and nausea.