Zika is an infectious disease caused by the Zika virus, which is transmitted to people by Aedes mosquitoes. Most people infected with Zika virus have no symptoms. If symptoms develop, the most common are fever, rash, joint pain, and/or red eyes. Symptoms usually begin a few days to a week after being bitten by an infected mosquito or having unprotected sex with an infected partner. The illness is usually mild with symptoms lasting for several days to a week. There are other causes of fever and painful joints. If you have recently traveled to an area where Zika virus is present or have recently had unprotected sex with an infected partner and you have these symptoms, your healthcare provider can order Zika and other tests to help determine the cause.
Zika virus infection in pregnant women can cause microcephaly (abnormally small head and brain) and other serious brain abnormalities in newborns. Read more about the relationship between pregnancy and Zika. Zika virus has also been associated with Guillain-Barré Syndrome (GBS), a rare autoimmune disease affecting the nervous system. Studies are ongoing to better understand the type of GBS that is apparently associated with Zika.
There is no specific treatment for Zika. Talk with your health care provider about medications to help reduce fever and pain; rest and fluids are also helpful. Most people will feel better in about a week.
Where does Zika occur?
Zika occurs in many tropical and sub-tropical areas of the world, particularly in Africa, Southeast Asia, and islands in the Pacific Ocean. Recent outbreaks have occurred in the Caribbean, Central and South America, and Mexico. Please visit the Centers for Disease Control & Prevention for the latest information on where Zika virus is circulating. Within the Zika-affected countries, travel to elevations higher than 6,500 feet (2000 meters) is considered to pose minimal risk.
How do people get Zika?
Zika virus is primarily transmitted by Aedes aegypti mosquitoes (also known as yellow fever mosquitoes) and by Aedes albopictus mosquitoes (also known as Asian tiger mosquitoes). These mosquitoes are not native to California. However, since 2011 they have been detected in several California counties (as displayed on the map, the invasive Aedes mosquitoes have been identified in the surrounding vector districts including Greater Los Angeles County Vector Control District and San Gabriel Valley Mosquito & Vector Control District).
An Aedes mosquito can only transmit Zika virus after it bites a person who has this virus in their blood. To date there has been no local mosquito-borne transmission of Zika in California. Thus far, Zika virus infections have been documented only in people who were infected while traveling outside the United States or through sexual contact with an infected traveler. Zika virus is not spread through casual contact such as touching or hugging an infected person.
What can people do to keep from getting Zika?
There is no vaccine to prevent Zika. In areas where Zika is present, everyone, including pregnant women and women of childbearing age, should protect themselves from mosquito bites.
- Apply EPA-registered mosquito repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol to exposed skin and clothing.
- Using insect repellent is safe and effective. Pregnant women and women who are breastfeeding can and should choose an EPA-registered insect repellent and use it according to the product label.
- 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. Ensure there are no holes in window/door screens and nets.
- Because of the potential transmission of Zika virus through sex, the risk for sexual transmission of Zika virus can be eliminated by abstinence and reduced by correct and consistent use of condoms.
- Both asymptomatic and symptomatic men who have traveled to an area of active Zika virus transmission and have a pregnant partner should abstain from sexual activity or use condoms consistently and correctly during sex for the duration of the pregnancy.
What can people do to help prevent Zika from becoming established in California?
- All travelers returning from an area with Zika to California should take steps to prevent mosquito bites for 3 weeks so they do not spread Zika to uninfected mosquitoes, even if the travelers do not feel sick. Men can consider abstaining from sex or using condoms consistently and correctly after returning from travel.
- If you are sick with fever, rash, red eyes, or joint pain within two weeks after returning from an area where Zika occurs, contact your healthcare provider and continue to avoid mosquito bites to help prevent possible spread of the virus.
- To reduce mosquito breeding, check your yard weekly for water-filled containers–even a small cap filled with water can serve as a breeding source for mosquitoes. Clean and scrub bird baths and pet-watering dishes weekly and dump the water from overflow dishes under potted plants and flower pots. Check that gutters are not holding water.
For more information about Zika, visit the following resources: