Photograph by David Goldman, AP
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A sunbather basks on Rio de Janeiro's Ipanema beach ahead of the 2016 Summer Olympics. Brazil is one of several countries with active cases of Zika virus.

Photograph by David Goldman, AP

How to Protect Yourself Against the Zika Virus

As our knowledge of the virus develops, here’s what you need to know to stay healthy.

This story was originally published on February 8, 2016, and updated August 19, 2016.

In the wake of outbreaks in Latin America, the Caribbean, and most recently the United States, the World Health Organization now believes that the mosquitoes that spread Zika virus, Aedes aegypti and Aedes albopictus—the same species that transmit dengue and chikungunya—will eventually make their way to all nations within the Western Hemisphere, excepting parts of Chile and Canada, where high elevation and colder climate may prevent the mosquitoes from breeding.

Mosquitoes, however, are not the only mode of transmission fueling the outbreak. The first sexually transmitted case was reported in Dallas, Texas, in early February, and the Centers for Disease Control and Prevention have since confirmed its status as a sexually transmitted infection.

The CDC recently issued an unprecedented travel warning advising pregnant women against all non-essential travel to Miami-Dade County, Florida, after a spike in cases—the first time the CDC has warned against travel in the continental United States.

“We’re in the midst of mosquito season and expect more Zika infections in the days and months to come,” said CDC Director Tom Frieden in a press release. As of August 2016, 2,260 cases of Zika have been reported in the continental United States and Hawaii, nearly a fourth of those cases in pregnant women. The CDC is now recommending that all pregnant women in the United States be evaluated for Zika virus exposure during prenatal care visits.

Here’s how travelers can protect themselves against the Zika virus:

  • New research on Zika is constantly developing; consult the CDC website for up-to-date information before making plans to travel.
  • If you are pregnant or hoping to become pregnant in the near future, avoid traveling to areas where the virus is actively circulating. If you present with symptoms of Zika you should consult with a health care provider about getting tested, and may be advised to delay pregnancy. Check the CDC website for up-to-date recommendations for pregnant women.
  • Both men and women can transmit Zika virus through sexual activity, including oral sex, even if they are asymptomatic. Always use condoms or dental dams when engaged in sexual contact.
  • If you decide to travel to affected areas, pack an ample supply of mosquito repellant. Varieties containing a chemical known as DEET in concentrations of 40 percent or higher are most effective, though Consumer Reports issued recommendations for top products that include milder plant-based ingredients, clothing, and mosquito netting.
  • If you are also using sunscreen, apply sunscreen before applying insect repellent.
  • Treat clothing and gear with permethrin (or buy items pre-treated with permethrin).
  • While staying in an affected area, make sure windows and window screens are fully closed when you sleep or protect yourself with mosquito netting.
  • Take anti-mosquito-bite precautions around the clock. Mosquitoes that transmit Zika are hard to avoid because they bite during the day, opposed to only in the evening.
  • Wear pants and long-sleeved shirts to cover exposed skin.
  • Avoid mosquito-breeding sites like bodies of standing water.
  • Aedes species mosquitoes acquire Zika by feeding on people who have already been infected, and continue to transmit the virus to others through their bite. Continue to protect yourself against mosquito bites even after returning from a Zika-affected area to prevent spreading the virus further.

Frequently asked questions (and their answers):

Q: What is the disease like?
A: For those who become sick, the illness is typically mild, with symptoms that include fever, rash, joint pain, and red eyes. However, Zika infection during pregnancy can cause serious birth defects, including microcephaly. While typically not fatal, Colombia recently reported Zika-related deaths.

Q: What happens once a person has been infected?
A: He or she is likely to be immune from future infections.

Q: Is there a vaccine to prevent Zika?
A: Not currently, though the medical community is actively pursuing methods to combat or eradicate the disease. The National Institutes of Health recently announced that it will begin its first human clinical trial of the NIAID Zika virus investigational DNA vaccine, however health experts warn that the development of an effective vaccine may take years.

Leslie Trew Magraw is an editor at National Geographic. Connect with her on Twitter and Instagram.