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Zika virus is a single-stranded RNA virus of the Flaviviridae family. It is related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses.


Zika virus spreads to people primarily through the bite of an infected Aedes species mosquito (Aedes aegypti and Aedes albopictus).

Mosquitoes that carry Zika are aggressive daytime biters and can also bite at night. A mosquito becomes infected when it bites a person already infected with Zika, and it can then spread the virus by biting more people.

Zika is also spread in other ways, including:

  • During sex with a person who has Zika to his or her partners.
  • From a pregnant woman to her fetus during pregnancy or around the time of birth.
  • Through blood transfusions (likely but not confirmed).


Most people infected with Zika will not have symptoms or will only have mild symptoms.

About 1 in 5 people infected with Zika will have one or more of the following symptoms:

  • Fever
  • Rash
  • Joint pain
  • Red eyes, or conjunctivitis
  • Muscle pain
  • Headache

These symptoms typically last up to one week.

Zika symptoms include conjunctivitis, fever, joint pain, and rash among other more serious consequences for pregnant women.

In pregnant women, Zika infection can have more serious consequences, including:

  • Microcephaly, a birth defect of the brain, which can result in fetal death, infant with a small head circumference, or infant whose brain has not developed properly.
  • Fetal or infant defects of the eye, hearing deficits, and/or impaired growth.

In rare cases, Zika virus can cause Guillan-Barre syndrome, a neurological disorder in which the immune system attacks nerves leading to weakness and temporary paralysis.    


There is currently no vaccine to prevent or medicine to treat Zika.

Pregnant women should not travel to areas with Zika. If you must travel to an area with Zika, talk to your healthcare provider.

If you or your partner is pregnant and live in or have traveled to an area with Zika, use condoms every time you have vaginal, anal, or oral sex or do not have sex for the entire pregnancy.

You can take the following measures to protect yourself from getting Zika through mosquito bites or sex:

  • Use Environmental Protection Agency (EPA)-registered insect repellant with one of the following active ingredients: DEET, Picaridin, IR3535, oil of lemon eucaplytus, or para-methane-diol.
  • Wear long-sleeved shirts and long pants.
  • Stay in places with air conditioning and window and door screens to keep mosquitoes outside.
  • Take steps to control mosquitoes inside and outside your home.
  • Sleep under a mosquito bed net if air conditioned or screened rooms are not available or if sleeping outdoors.
  • Prevent sexual transmission of Zika by using condoms or not having sex.

Learn more about Zika prevention, visit CDC.


Physicians diagnose Zika based on a patient’s symptoms, exposure, and recent travel history.

Blood or urine testing can confirm Zika infection.

Zika virus testing is recommended only for certain people. If you have questions or think you should be tested, talk to your healthcare provider.

If you are pregnant or you have symptoms of Zika, then Zika testing is recommended if:

  • You live in or traveled to an area with Zika.
  • You had sex with a partner who lives in or traveled to an area with Zika.

To learn more about testing visit CDC.


People with Zika usually do not get sick enough to go to the hospital and very rarely die from Zika.

If you have symptoms of a Zika infection:

  • Get plenty of rest.
  • Drink fluids to prevent hydration.
  • Take medicines like acetaminophen (Tylenol®) to reduce your fever.
  • Do not take aspirin or non-steroidal anti-inflammatory drugs (NSAIDS) until dengue is ruled out to reduce the risk of bleeding.

Once you have been infected with Zika, you are likely to be protected from future infections.