Zika virus is most commonly spread to people by the bite of an infected Aedes species mosquito. It can also be spread through sex from a person who is infected with Zika virus to their sexual partner.

Zika virus typically occurs in tropical and subtropical areas of Africa, the Americas, Southern Asia, and Western Pacific.

Zika causes symptoms similar to other viral diseases spread through mosquito bites, like dengue and chikungunya. Zika virus can be passed from a pregnant woman to her baby. Infection during pregnancy can cause certain birth defects.

Transmission

Zika virus is primarily transmitted to people through the bite of an infected Aedes species mosquito (Aedes aegypti and Aedes albopictus). These mosquitoes are the same mosquitoes that spread dengue and chikungunya. These mosquitoes typically lay eggs in standing water in containers like buckets, bowls, animal dishes, flowerpots, and vases. They like to bite people and live both indoors and outdoors. They bite both during the day and night.

A mosquito gets infected with Zika virus when it bites an infected person during the period of time when the virus can be found in the person’s blood, typically only through the first week of infection. Infected mosquitoes can then spread the virus to other people through bites.

Zika virus can be passed through sex from a person who has Zika to their partners, even if the infected person does not have symptoms at the time.

Symptoms

Many people infected with Zika virus will not have symptoms or will only have mild symptoms. Common symptoms of Zika include:

  • Fever
  • Rash
  • Headache
  • Joint pain
  • Conjunctivitis (red eyes)

Zika symptoms usually last for several days to a week. People usually do not get sick enough to go to the hospital. For this reason, many people might not realize they have been infected.

Individuals at Risk for Severe Illness

Pregnant Women

Zika infection during pregnancy can cause serious birth defects and is associated with other pregnancy problems, including fetal loss, stillbirth and preterm birth.

Treatment

There are no medicines to treat Zika. However, the symptoms of Zika can be treated. Contact your health care provider if you are experiencing Zika symptoms.

Information for Travelers

Follow mosquito-borne disease prevention strategies if you are traveling to a tropical or sub-tropical area (Africa, South America, Southern Asia, and Western Pacific).

View travel health notices when traveling internationally to understand any local risks.

Surveillance and Data
Information for Health Care Providers