Zika Virus


Zika is a mosquito-borne virus, similar to dengue fever, yellow fever and West Nile virus. The infection is associated with a birth defect called microcephaly, which can affect babies born to people who become infected with Zika while pregnant.

What You Need to Know

  • Symptoms of Zika are mostly mild, with only 1 in 5 infected people exhibiting any signs of illness. Hospitalization is rare with this infection.
  • Zika can be diagnosed through a blood test.
  • The Centers for Disease Control and Prevention keeps an updated list of countries where Zika outbreaks have occurred. Pregnant women should speak to their obstetrician-gynecologist if they must travel to an affected area, and take precautions to prevent mosquito bites.
  • There is currently no vaccine or antiviral treatment for Zika.
  • Treatment addresses symptoms, and cases clear up on their own.

What is Zika?

Zika is an infectious disease caused by a virus. The virus is carried by infected mosquitoes, including the Aedes aegypti and Aedes albopictus species, which are found throughout the Americas.

The infection itself (sometimes called Zika fever) is usually mild and goes away on its own. However, the impact of the virus has most significantly been seen in pregnant women and their fetuses.

Zika in Pregnancy

If you are pregnant and have traveled to a location where Zika virus cases have been reported, please contact your doctor as soon as possible.

People who are pregnant or are planning to become pregnant are at the greatest risk for the Zika virus if traveling to an area with ongoing outbreaks. While it is unknown if pregnancy itself increases vulnerability to the virus, Zika can cross the placenta and affect the fetus. With that in mind, pregnant people should delay traveling to areas where Zika outbreaks are ongoing. Likewise, those considering pregnancy should speak with their obstetrician-gynecologists about prospective travel to areas with Zika outbreaks. The Centers for Disease Control and Prevention keeps an updated list of affected countries.

Those who have recently traveled to an area affected by Zika virus and who exhibit symptoms should wait eight weeks before trying to get pregnant.

If I’ve had Zika in the past, am I at risk for giving birth to a baby with microcephaly?

There is no evidence to suggest that Zika virus presents a risk of birth defects for future pregnancies after it has cleared from the bloodstream. Zika virus usually remains in the blood of an infected person for about a week, but may be present longer in semen and urine. The virus may last longer in the blood of a pregnant woman.

How is Zika spread?

  • Zika virus is primarily spread through the bite of infected mosquitos.
  • If a pregnant woman is bitten by an infected mosquito, the infection can cross the placenta, infecting the fetus.
  • The virus has also been transmitted through blood transfusion or laboratory exposure. The U.S. Food and Drug Administration has published guidelines to help protect the blood supply.

Can I get Zika from sex?

Yes: Sexual transmission of the Zika virus can occur. Transmission has been reported from infected men and women to their sexual partners through anal, oral or vaginal sex. If a man travels to an area of active Zika virus infection and has a pregnant partner, they should abstain from sexual activity or consistently and correctly use condoms during sex for the duration of the pregnancy.

How to Prevent Zika Virus Infection

The best way to protect yourself is to limit your exposure by not traveling to countries where Zika outbreaks are happening. If you must travel to an affected area, avoid mosquito bites by taking these steps:

  • Wear long-sleeved shirts and long pants to limit skin exposure.
  • Stay indoors in screened-in or air-conditioned rooms as much as possible.
  • Use mosquito netting.
  • Pregnant women can safely use Environmental Protection Agency-approved bug spray with DEET or picardin, or wear permethrin-infused clothing.

Zika Virus Symptoms

Only about 1 in 5 people infected with Zika will exhibit symptoms, and they will be mostly mild. The most common symptoms of Zika virus infection are:

  • Fever
  • Zika rash: red spots that may be flat, raised or both
  • Arthralgia (joint pain)
  • Conjunctivitis (red, inflamed eyes)
  • Headache

Symptoms will usually last several days to a week, and clear up on their own. It is rare for Zika virus to cause severe illness that requires hospitalization.

Zika Diagnosis

Zika virus infection is diagnosed by a blood test. A urine test may also be appropriate if you have recently had or currently have symptoms.

Zika Treatment

Treatment for Zika virus infection addresses symptoms, which are mild in most people. Your doctor may recommend:

  • Rest
  • Drinking plenty of fluids
  • Taking acetaminophen for fever

If you are pregnant, you will continue to undergo regular monitoring by your maternal-fetal medicine specialist to watch for fetal abnormalities after your symptoms have passed.

Antiviral treatment is being investigated, but there is currently no vaccine or medication available to prevent or treat Zika virus infection.