Zika is a virus that a person can get from being bitten by an infected mosquito. It also can be spread by sexual contact. The virus is of particular concern for pregnant women and women who may become pregnant.

More to Know

Zika virus causes a serious birth defect called microcephaly, a rare condition in which a child's brain doesn't fully develop, resulting in an abnormally small head. It also has been linked to other serious problems in fetuses, such as eye defects, impaired growth, and other brain problems.

The virus is a particular threat in Latin America, the Caribbean, and the Pacific Islands. Zika-spreading mosquitoes also have been found in the United States (Florida and Puerto Rico), and some people in the United States have Zika infections. 

Often, Zika causes no symptoms. When it does, symptoms are mild and can include fever, rash, joint pain, and pinkeye.

Keep in Mind

If you're pregnant or trying to become pregnant, experts say you should postpone travel to countries where Zika virus has been found. If you do visit these countries, it's very important to try to avoid mosquito bites by covering up and using insect repellents. It's best to use condoms during sex when visiting countries where Zika is active, and to postpone pregnancy after the visit, especially if you or your partner might have become infected with Zika. If you're living in an area where Zika is active, talk to your doctor about pregnancy planning. There is no vaccine or treatment for Zika virus.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.