Zika virus is spread to people through mosquito bites. The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon.

Zika Signs and Symptoms

Most people infected with Zika virus do not have any symptoms at all.  Among those who do, the most common symptoms are fever, rash, joint pain, or conjunctivitis (red eyes).  Other common symptoms include muscle pain and headache.  The illness is usually mild with symptoms lasting for several days to a week.  Severe disease causing hospitalization or death is rare.

Zika Transmission (How it Spreads)

Zika virus is transmitted to people primarily through the bite of an infected Aedes mosquito.  These are the samemosquitoes that spread dengue and chikungunya viruses.  Aedes mosquitoes are aggressive daytime biters, prefer to bite people, and live indoors and outdoors near people.  Mosquitoes become infected when they feed on a person already infected with the virus.  Infected mosquitoes can then spread the virus to other people through bites.

Zika virus can be transmitted from a mother to her baby.  Zika virus ia a cause of microcephaly and other severe birth defects.  A mother already infected with Zika virus can pass the virus to her baby during pregnancy or around the time of the baby's birth.  To date, there are not reports of infants getting Zika virus through breastfeeding.  Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where Zika virus is found.

Zika virus can be transmitted during sex, even if the infected person does not have symptoms at the time.  It can be passed from man to man, from man to woman, from woman to man, and from woman to woman during sexual activities.  Studies are underway to fund out how long Zika virus stays in the semen and vaginal fluids of people who have Zika virus and how long it can be passed to sexual partners.  We know that Zika can remain in semen longer than in other body fluids, including vaginal fluids, urine, and blood.  Zika virus may also be spread through blood transfusions.  

Zika Virus Prevention

No vaccine or medications are available to prevent or treat Zika infections.  Prevent Zika by avoiding mosquito bites when traveling to countries where Zika virus is present:

• Use insect repellents.  When used as directed, insect repellents are safe and effective for everyone, including pregnant and nursing women.  Most insect repellents can be used on children.  Do not use products containing oil of lemon eucalyptus in children under the age of 3 years.  Repellents containing DEET, picaridin, IR3535, and some oil of lemon eucalyptus and para-menthane-diol products provide long lasting protection.
• If you use both sunscreen and insect repellent, apply the sunscreen first then the repellent.  Do not spray insect repellent on the skin under your clothing.
• Treat clothing with permethrin or purchase permethrin-treated clothing.
• Always follow the label instructions when using insect repellent or sunscreen.
• When weather permits, wear long-sleeved shirts and long pants.
• Use air conditioning or window/door screens to keep mosquitoes outside.  If you are not able to protect yourself from mosquitoes inside your home or hotel, sleep under a mosquito bed net.

Using condoms can help reduce the chance of getting Zika from sex.  Condoms include external ("male") and internal ("female") condoms.  To be effective, condoms should be used from start to finish every time during vaginal, anal, and oral sex and during sexual activity with shared sex toys.  Dental dams may also be used for certain types of oral sex (mouth to vagina or mouth to anus).  Not having sex eliminates the risk of getting Zika from sex.

Zika Virus Surveillance Data

The Aedes mosquitoes that carry Zika virus have not been found in Monterey County to date.  However, they are present in several areas of California.  Visit the California Department of Public Health's website for a map of areas in California where Aedes mosquitoes are present.

Please click to view the Communicable Disease dashboard with local Zika virus data available in English and Spanish.

California data is available at the California Department of Public Health’s Zika website.

United States data is available at the Centers for Disease Control and Prevention’s Zika website.

For More Information

Click here to visit the CDC's Zika Virus website

Click here to visit the California Department of Public Health's Zika Virus website

For Healthcare Professionals

CDC Clinical Signs and Symptoms of Zika

CDC Clinical Considerations for Pregnant Persons with Possible Zika Virus Disease

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