County of Marin Health and Human Services

Information on Zika Virus


Because Zika infection during pregnancy may cause severe birth defects, pregnant women should not travel to the areas with active Zika Virus transmission. Partners of pregnant women and couples considering pregnancy should know the risks to pregnancy and take prevention steps. All travelers should strictly follow steps to prevent mosquito bites and prevent sexual transmission during and after the trip.

Updated Guidance for Timing of Pregnancy after Zika Exposure

CDC now recommends that men with possible Zika virus exposure who are planning to conceive with their partner wait at least 3 months after symptoms or possible exposure (travel to or residence in an area with risk of Zika). These updated recommendations are based on emerging data, which suggest that risk of infectious Zika virus in semen appears to decline substantially during the 3 months after onset of symptoms.

Men with possible Zika virus exposure whose partner is pregnant should use condoms or the couple should not have sex for the entire pregnancy to reduce the risk of transmission. 

The invasive mosquito responsible for ZIKV transmission has not been found in Marin County.  To date, there have been no locally-acquired, mosquito-borne cases of ZIKV disease in Marin County, the Bay Area, or California.  

What is the Zika virus?

Zika virus disease is caused by the Zika virus, which is spread to people primarily through the bite of an infected mosquito

How does Zika virus spread?

Zika is spread to people primarily through the bite of an infected Aedes species mosquito (Aedes aegypti and Aedes albopictus). A pregnant woman can pass Zika virus to her fetus during pregnancy or around the time of birth. Also, a man infected with Zika virus can pass it to sex partners.  

What are the symptoms of Zika?

The most common symptoms of Zika virus disease are fever, rash, joint pain, and red eyes. Other symptoms include muscle pain and headache. Many people infected with Zika won’t have symptoms or will have mild symptoms, which can last for several days to a week.

How is Zika diagnosed?

To diagnose Zika, your doctor will ask you about recent travel and symptoms you may have, and collect blood or urine to test for Zika or similar viruses. 

How is Zika treated?

Zika virus disease is usually mild and requires no specific treatment. People sick with Zika virus should get plenty of rest, drink enough fluids, and treat pain and fever with acetaminophen. If symptoms worsen, they should seek medical care and advice.

How can Zika be prevented?

The best way to prevent Zika is to protect yourself and your family from mosquito bites:

Zika can be spread by men to their sex partners. People whose male sex partners have traveled to or live in an area with Zika can prevent Zika by using condoms correctly every time they have sex or by not having sex.

What is the risk of Zika in pregnancy?

Microcephaly and other problems (eye defects, hearing loss, and impaired growth) have been detected among fetuses and infants infected with Zika virus before birth.

Is there a Zika vaccine?

Currently, no vaccine or medication exists to prevent or to treat Zika virus infection.