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Mosquito-Borne Diseases

General information

West Nile Virus

While human cases of West Nile virus are rare in San Mateo County, it’s a good idea to practice prevention and avoid mosquito bites. Although most people who become infected with the virus never develop any symptoms, some people may develop a more serious illness, such as meningitis or encephalitis. WNV is a seasonal epidemic in North America that flares up in the summer and continues into the fall. 

General information

Traveled Abroad Recently? Things to Know about Zika Virus

Zika virus is primarily spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and red eyes. The illness is usually mild with symptoms lasting from several days to a week. It can also be transmitted from a pregnant mother to her baby during pregnancy or around the time of birth.

Outbreaks of Zika have occurred in parts of Africa, Southeast Asia, the Pacific Islands, and Latin America.