Transmission and Risks

Most people get Zika from a mosquito bite. Transmission is also possible through sex with an infected person and from mother to child during pregnancy.

Through mosquito bites
Zika virus is transmitted to people primarily through the bite of an infected mosquito. These are the same mosquitoes that spread dengue and chikungunya viruses.
  • 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 that spread chikungunya, dengue, and Zika are agressive daytime biters, but they can also bite at night.
  • 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.
From mother to child
  • A pregnancy woman can pass Zika virus to her fetus during pregnancy. Zika is a cause of microcephaly and other severe fetal brain defects. The CDC continues to study the full range of other potential health problems that Zika virus infection during pregnancy may cause.
  • A pregnant women already infected with Zika virus can pass the virus to her fetus during the pregnancy or around the time of birth.
  • 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 where Zika virus is found.
Through sex
  • Zika can be passed through sex from a person who has Zika to his or her partners. Zika can be passed through sex, even if the infected person does not have symptoms at the time.
    • It can be passed from a person with Zika before their symptoms start, while they have symptoms, and after their symptoms end.
    • Though not well documented, the virus may also be passed by a person who carries the virus but never develops symptoms.

RISKS
Anyone who lives in or travels to an area where Zika virus is found and has not already been infected with Zika virus can get it from mosquito bites. Once a person has been infected, he or she is likely to be protected from future infections.