Yellow fever is a virus transmitted by the bite of an
infected mosquito. It has been found in areas of South America
What are the signs and symptoms of yellow fever?
Symptoms of yellow fever usually begin 3-6 days after
infection, and include fever, chills, severe headache, back pain,
body aches, nausea and vomiting, fatigue, and weakness. These are
rarely followed by a more severe form of yellow fever, including
jaundice, bleeding, high fever, and organ failure.
How can I get yellow fever ?
Yellow fever is transmitted through the bite of an infected
mosquito. It cannot be transmitted directly from person to
Can I get yellow fever in San Mateo County?
Yellow fever is not currently present among mosquitoes in
San Mateo County. However, a species of mosquito capable of
transmitting yellow fever, Aedes aegypti, has been found in San
Mateo County recently. Local mosquitoes could become infected by
feeding on someone with an active case of yellow fever . For
this reason, the District works closely with the County Health
Department on all mosquito-borne disease cases. When a
mosquito-borne disease is detected in a patient in San Mateo
County, the health department notifies the District. District
staff will then conduct mosquito surveillance in the area to
ensure that vector mosquitoes are kept at very low numbers.
What can I do if i am traveling to a country that has yellow
A vaccine is available for yellow fever. Travelers are also
advised to avoid mosquito bites. For information on protecting
yourself from mosquito bites, see What You Can Do: Mosquitoes.