A Zika infection is caused by a virus. It is often passed from an infected mosquito. It may cause flu-like problems in some, but does not cause problems in most people. It can cause serious birth defects in babies who are still in the womb.
A specific type of mosquito can pick up Zika when it bites a person with the infection. The mosquito can then pass the virus to the next person it bites. Most Zika infections pass this way.
Zika can also pass from person to person. It may pass:
The risk is greater in those who have spent time in a high-risk place without mosquito protection. Zika happens in:
Symptoms do not always happen. If they do, they may show up a few days after the bite. These problems may last a few days to a week:
Zika infection in pregnant women may cause these problems for the baby:
The doctor will ask about your risk of exposure to Zika from travel or sex.
A blood test is needed to confirm Zika. It will look for the virus or signs that the body has fought the virus. It may be given to pregnant women who:
A woman with a positive test will need to see a maternal-fetal or infectious disease specialist.
Medicine cannot treat Zika. Symptoms should pass on their own in a week. Rest and fluids can help.
Acetaminophen may be given to ease fever or pain. Nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin can cause problems in women with dengue infection.
If a mosquito bites a person who is infected, it can pass the infection to someone else. Steps will be needed to avoid mosquito bites for about a week.
The Zika virus may stay in the body or in sperm for a short time even after symptoms go away. To lower the risk of passing the virus to a new fetus:
Pregnant women who live in areas without Zika should not travel to places where it is spreading. Those in areas with Zika should take steps to not get bit by mosquitoes. They should also use a condom during sex or not have sex with a male partner who has lived in or traveled to an area with Zika.
Centers for Disease Control and Prevention
World Health Organization
The Society of Obstetricians and Gynaecologists of Canada
Pregnant women: how to protect yourself. Centers for Disease Control and Prevention website. Available at:
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Updated February 26, 2019. Accessed November 6, 2019.
World Health Organization. Interim guidance on pregnancy management in the context of Zika virus. WHO 2016 May 13.
Zika virus in pregnancy and congenital Zika syndrome. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/zika-virus-in-pregnancy-and-congenital-zika-syndrome. Updated February 5, 2018. Accessed November 6, 2019.
Zika virus infection. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/zika-virus-infection. Updated July 18, 2019. Accessed November 6, 2019.
Last reviewed November 2019 by EBSCO Medical Review Board Elliot Levine, MD