Zika is a mosquito-borne virus, similar to dengue fever, yellow fever or West Nile virus. The virus is predominantly transmitted by infected Aedes aegypti mosquitos, which are found throughout the Americas. Transmission can also occur by intrauterine infection — if a mother is bitten by an infected mosquito and becomes infected, Zika can cross the placenta, affecting the fetus. Reports have also documented transmission at the time of delivery.

There have been some cases of sexual transmission and contraction through blood transfusion or laboratory exposure. These transmissions are thought to only be possible during the incubation period, which is approximately three to 12 days.

While anyone can contract Zika, the impact of the virus has most significantly been seen in pregnant women and their fetuses. Zika during pregnancy has been associated with microcephaly — a condition in which an infant’s head is substantially smaller than expected, leading to developmental issues — and other neurologic abnormalities.

What are the symptoms of Zika?

These are the most common symptoms of the Zika virus:

  • Fever

  • Maculopapular rash

  • Arthralgia (joint pain)

  • Conjunctivitis

  • Headache

Only about one in five infected individuals will exhibit symptoms, and they will be mostly mild. Symptoms will usually last several days to a week. It is rare to require hospitalization for the Zika infection.

How is Zika diagnosed?

If you are not pregnant and exhibit Zika symptoms, your physician will perform a blood test for evidence of Zika virus infection.

If you are pregnant and have traveled to a Zika-affected country, your physician will perform a blood test, even if you are not exhibiting any symptoms. You will also have at least one ultrasound to evaluate your fetus for infection.

How is Zika treated?

Antiviral treatment is being investigated, but there is currently no vaccine or medication available to prevent or treat Zika infection. If you are exhibiting symptoms, get plenty of rest and drink fluids to prevent dehydration. You may use 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.

Who is at risk for Zika?

Women who are planning to become pregnant or are currently 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 a woman’s vulnerability to the virus, Zika can cross the placenta and affect the fetus. There has been a high rate of birth defects seen among babies whose mothers came in contact with Zika during pregnancy.

How can Zika be prevented?

The best way to prevent Zika is to avoid exposure. Pregnant women should delay traveling to areas where Zika outbreaks are ongoing. Women who are 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.

If you have to travel to areas where Zika has been reported, take precautions to avoid mosquito bites:

  • Use Environmental Protection Agency-approved insect repellent and follow the product label. Pregnant women can safely use these approved repellents.

  • Cover any exposed skin if you have to go outside.

  • Stay in air-conditioned and screened-in areas.

Additionally, 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.

If you are pregnant and have traveled to a country where Zika virus cases have been reported, please contact your health care provider as soon as possible.