Zika is spread mostly through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). These mosquitoes bite during the day and night. It can be passed from a pregnant woman to her fetus. Infection during pregnancy can cause certain birth defects. Currently, there is no vaccine or medicine for Zika—which is why prevention is so important.
Many people infected with Zika virus won’t have symptoms or will only have mild symptoms. The most common symptoms of Zika are
Symptoms can last for several days to a week. People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika. Once a person has been infected with Zika, they are likely to be protected from future infections.
A blood or urine test can confirm a Zika infection. Diagnosis is based on a person’s recent travel history, symptoms, and test results. Your doctor or other health care provider may order tests to look for several types of infections.
Zika can be transmitted many ways: through mosquito bites, sex, blood transfusion, laboratory exposure, and from mother to child.
Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito. These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots, and vases. They 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.
A pregnant woman can pass Zika virus to her fetus during pregnancy. Zika can cause microcephaly and other severe fetal brain defects. We are studying the full range of other potential health problems that Zika virus infection during pregnancy may cause.
To date, there are no reports of infants getting Zika virus through breastfeeding. Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas with risk of Zika.
Zika can be passed through sex from a person who has Zika to his or her partners even if the infected person does not have symptoms at the time. Learn how to protect yourself during sex.
Though not well documented, the virus may also be passed by a person who carries the virus but never develops symptoms.
Studies are underway to find out how long Zika stays in the semen and vaginal fluids but we know that Zika can remain in semen longer than in other body fluids, including vaginal fluids, urine, and blood.
Anyone who lives in or travels to an area with risk of Zika and has not already been infected with Zika virus can get it from mosquito bites.
Use Environmental Protection Agency (EPA)-registered insect repellents. When used as directed, EPA-registered insect repellents (including DEET) are proven safe and effective, even for pregnant and breastfeeding women.