REDWOOD CITY (CBS SF) – San Mateo County’s Mosquito and Vector Control District discovered West Nile virus in a dead bird this week, the first case in the county since 2018.
The bird – an American crow – was collected in South San Francisco earlier this week, the vector control district said Wednesday. Although reports of dead birds suggest the presence of the virus, the risk to humans remains small.
West Nile virus primarily affects birds, but humans, horses, and other animals can be infected if they are bitten by an infected mosquito, which are vectors for the virus. The virus cannot be transmitted from person to person.
The county’s vector control district encouraged people to report fresh bird carcasses to the California West Nile Virus Hotline at www.westnile.ca.gov or by calling (877) WNV-BIRD.
People can reduce the risk of infection by preventing mosquito formation and by avoiding mosquito bites. Because mosquitoes lay their eggs on stagnant water, the district recommends draining and disposing of stagnant water on property – including flower pots, old car tires, clogged gutters and dog bowls.
District officials also recommend wearing clothing and mosquito repellent outside in the early hours of the morning and evening, as it is during these times that the mosquitoes that carry the virus are prone to bite. Doors and windows should have close-fitting screens to keep mosquitos out. Mosquito repellants that contain ingredients such as DEET, Picaradin, lemon eucalyptus oil or IR3535 can prevent mosquito bites.
The district will continue to treat mosquito breeding sources and collect mosquitoes for testing in areas where dead birds are found.
For help with a mosquito problem, contact the district at (650) 344-8592 or visit http://www.smcmvcd.org for more information.
The West Nile virus was also found in Contra Costa and Santa Clara counties that year.
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