Skip to main content


May contain: stain
This digitally-colorized transmission electron microscopic (TEM) image depicts numerous Chikungunya virus particles, which are composed of a central dense core that is surrounded by a viral envelope. Each virion is approximately 50nm in diameter. (CDC/ Cynthia Goldsmith, James A. Comer, and Barbara Johnson)

What is chikungunya?

Chikungunya is a virus transmitted by the bite of an infected mosquito. It has been found in many parts of the world, including recently the Caribbean, South and Central America, and North America.

What are the signs and symptoms of chikungunya?

Symptoms of chikungunya usually begin 3-7 days after infection, and include fever, severe joint pain, headache, muscle pain, joint swelling, or rash. Chikungunya is not usually fatal, but may cause severe pain and discomfort.

How can I get chikungunya?

Chikungunya is transmitted through the bite of an infected mosquito.

Can I get chikungunya in San Mateo County?

Chikungunya is not currently present among mosquitoes in San Mateo County. However, a species of mosquito capable of transmitting chikungunya, Aedes aegypti, has been found in San Mateo County recently. Local mosquitoes could become infected by feeding on someone with an active case of chikungunya. 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 chikungunya?

There is currently no vaccine or medication to prevent infection with chikungunya. Travelers are advised to avoid mosquito bites. For information on protecting yourself from mosquito bites, see What You Can Do: Mosquitoes.

Join our mailing list