Zika virus disease is caused by the Zika virus, which is spread to people primarily through the bite of an infected mosquito (Aedes aegypti and Aedes albopictus). The illness is usually mild with symptoms lasting up to a week, and many people do not have symptoms or will have only mild symptoms. However, Zika virus infection during pregnancy can cause a serious birth defect called microcephaly and other severe brain defects.

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.

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 to her fetus during pregnancy or around the time of birth. Also, a person with Zika can pass it to his or her sex partners. We encourage people who have traveled to or live in places with Zika to protect themselves by preventing mosquito bites and sexual transmission of Zika.

Many people infected with Zika will have no symptoms or mild symptoms that last several days to a week. However, Zika infection during pregnancy can cause a serious birth defect called microcephaly and other severe fetal brain defects. Current research suggests that Guillain-Barre syndrome (GBS), an uncommon sickness of the nervous system, is strongly associated with Zika; however, only a small proportion of people with recent Zika virus infection get GBS.

Once someone has been infected with Zika, it’s very likely they’ll be protected from future infections. There is no evidence that past Zika infection poses an increased risk of birth defects in future pregnancies.

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

• Use Environmental Protection Agency (EPA)-registered insect repellents
• Wear long-sleeved shirts and long pants
• Sleep under a mosquito bed net if air conditioned or screened rooms are not available or if sleeping outdoors.

Zika can be spread by a person infected with Zika to his or her sex partners. People whose partners have traveled to or live in an area with Zika can prevent Zika by using condoms (or other barriers that protect against infection) every time they have sex or by not having sex.

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.

Travelers who go to places with Zika can be infected with Zika, and CDC has issued travel notices for people traveling to those areas. Many people will have mild or no symptoms. However, Zika can cause microcephaly and other severe birth defects. For this reason, pregnant women should not travel to any area with Zika, and women trying to get pregnant should talk to their doctors before traveling or before their sex partners travel. It is especially important that women who wish to delay or avoid pregnancy consistently use the most effective method of birth control that they are able to use. Those traveling to areas with Zika should take steps during and after they travel to prevent mosquito bites and sexual transmission of Zika.

Pregnant women who have recently traveled to an area with Zika should talk to their doctor about their travel, even if they don’t feel sick. Pregnant women should see a doctor if they have any Zika symptoms during their trip or within 2 weeks after traveling. All pregnant women can protect themselves by avoiding travel to an area with Zika, preventing mosquito bites, and following recommended precautions against getting Zika through sex.

Zika virus testing is performed at CDC and some state and territorial health departments. See your doctor if you have Zika symptoms and have recentlybeen in an area with Zika. Your doctor may order tests to look for Zika or similar viruses like dengue and chikungunya.

No. Pregnant women should not travel to any area with Zika. Travelers who go to places with outbreaks of Zika can be infected with Zika, and Zika infection during pregnancy can cause microcephaly and other severe fetal brain defects.