Maybe it's a dive trip to Belize. Or a cruise in the Caribbean. Or maybe you've snagged tickets to the summer Olympics in Rio. If you're traveling in places where Zika is circulating, there are a few things you need to keep in mind — and bring along.
The first question is: Should you go on the trip at all?
If you're pregnant — or trying to get pregnant — stop reading now and consider canceling that trip, says Catherine Spong, the acting director of the National Institute of Child Health and Human Development. "Having Zika anytime during pregnancy is associated with risk for the fetus," she says.
And even if you're just thinking about getting pregnant in the next few months, you might want to reconsider a trip to Latin America, the Caribbean or the Pacific Islands. Yes, guys, I'm talking to you, too!
Why? Because after you return from a Zika-affected area, you should wait at least eight weeks before trying to conceive, the Centers for Disease Control and Prevention says — even if you felt fine the entire trip. About 80 percent of people who catch the mosquito-borne virus don't have any symptoms. They don't even know they got infected.
If men do show signs of Zika, like a rash or fever, they should wait six months before trying to conceive. The virus can linger in semen for several months, the CDC says.
Now, if you're not in the baby-making business anytime soon, traveling to Zika-affected areas is safe, the CDC says. You just need to take a few precautions to lower your risk of catching the virus:
1. Put a helmet on that soldier. Zika can be transmitted sexually. So practice safe sex — or abstain — while traveling. "Use condoms correctly and consistently," the World Health Organization says, and continue to use them eight weeks after you get home.
2. Be sure there's running water and flushable toilets. Mosquitoes thrive in neighborhoods without running water or sewage systems, WHO says. These communities tend to have more standing water, where mosquitoes breed. So you're more likely to get bitten — and to get Zika.
These neighborhoods also tend to be overcrowded, which creates the perfect environment for Zika to spread, says Dr. Karin Nielsen, a pediatric infectious disease expert at UCLA. "You have to have clusters of people, who are sick, for mosquitoes to efficiently transmit Zika."
So it's best to avoid crowded, poor neighborhoods if you can.
3. The three "Ls" can keep mosquitoes away.
Long-lasting bug repellent: "Short-acting ones don't seem to work [for Zika-carrying mosquitoes]," Nielsen says.
DEET is the gold standard for long-acting sprays. A repellent with about 20 percent DEET will last five hours. And the CDC says it's safe for pregnant women.
"But doctors in Brazil are recommending the repellent picaridin for pregnant women," Nielsen says. "It lasts for about 10 hours. And it's less toxic than DEET."
Also, picaridin seems to keep mosquitoes at a greater distance than DEET, NPR reported earlier this year.
If you do go with DEET, stick to repellents with concentrations between 20 and 30 percent, the CDC says. Lower concentrations wear off more quickly. Higher concentrations can be toxic for children, the CDC says.
Long sleeves and pants: Mosquitoes love spaghetti straps and short shorts. The more skin you bare, the more bites you'll get.
And don't think that you're in the clear during the day. "The mosquitoes that spread Zika bite during the daytime, not around sunset or during the night," says Thomas Scott, an epidemiologist at the University of California, Davis.
So cover up those elbows, knees and toes, even during the day, he suggests.
Light-colored clothes: Mosquitoes that carry Zika — called Aedes aegypti — are attracted to black clothing, a scientist figured out back in 1938.
Red and violet look black to A. aegypti mosquitoes, so these colors also attract the insects, researchers wrote in a study published in 1966. "An increase in black-white interface in a checkerboard pattern [on clothing], or indeed any flicker effect, made an object yet more attractive to A. aegypti," the researchers added.
So when you're around mosquitoes, stick to clothes that are white, beige or yellow. Save the black and checkers for nighttime when A. aegypti mosquitoes aren't around.
4. Stay in places with screens or crank up the A/C.
A study published in March found window screens are the most effective way to reduce the risk of dengue — a virus similar to Zika that's also spread by A. aegypti. Screens reduced the risk of infection by 80 percent.
"Mosquitoes that carry Zika like to enter people's homes," says virologist Scott Weaver, at the University of Texas Medical Branch in Galveston. "So use screens or air conditioning. Otherwise, you have to protect yourself from mosquitoes even inside your home."
5. What to do when you return home.
Finally, after you get back to the States, be a good citizen. You could have an infection even if you don't feel sick. So if you live in a place with A. aegypti mosquitoes, keep up these precautions for a few weeks, Weaver says.
"Just a pay a little more attention to keeping mosquitoes out of your home or not encountering them outside," Weaver says. "That can go a long way to reducing the risk of triggering an outbreak here in the States." Or just passing the mosquito-borne virus to a friend or family member.
ARI SHAPIRO, HOST:
It's the time of year when thoughts turn to vacation. Maybe it's a dive trip to Belize, a cruise in the Caribbean or the Summer Olympics in Rio de Janeiro. The threat of Zika hangs over all these tropical getaways. The mosquito-borne virus is making its way north from South America. So if you're actually traveling to any of these places, there are some precautions you should take. NPR's Michaeleen Doucleff explains.
MICHAELEEN DOUCLEFF, BYLINE: So the first question is, should you take this trip at all? This is really a question for couples pregnant or planning to have a baby. The real danger from Zika is birth defects, and getting infected at any time during pregnancy can be dangerous. So Dr. Marty Cetron at the Centers for Disease Control and Prevention says, if you're pregnant, don't go.
MARTY CETRON: The most important message, and I think it's really, really key to get this out and it amplify it, is that pregnant women should avoid traveling to Zika-affected areas whenever possible.
DOUCLEFF: And even if you're not pregnant now, but trying, Cetron says couples might want to cancel their trip.
CETRON: If it were my daughter and they were actively trying to conceive, I would probably counsel them to avoid the risk of being in a Zika area, simply because you don't always really know when you're pregnant until you're maybe pretty far along.
DOUCLEFF: The CDC also recommends waiting to get pregnant after you get back from a Zika-infected area. If you didn't get sick, still wait at least eight weeks before trying. And if a man gets Zika symptoms, like a rash or a fever, the couple should wait six months.
CETRON: Because the virus can persist in semen as long as 62 days and perhaps longer.
DOUCLEFF: Zika can cause neurological complications in people other than pregnant women. These are rare, and health experts say you just need to take two precautions to lower your risk. First off...
PETER HOTEZ: Avoid sexual transmission, particularly from a male partner to a female partner.
DOUCLEFF: That's Dr. Peter Hotez at Baylor College of Medicine in Houston. He said scientists first thought Zika was spread almost exclusively by mosquitoes, but...
HOTEZ: We're seeing more and more cases of sexual transmission, so I think we have to continue to take that route very seriously.
DOUCLEFF: So use condoms. The second precaution is obvious - don't get bitten by mosquitoes. And the best way to do that, Hotez says, is pick the right hotel or resort.
HOTEZ: You want to make certain that you're in a place that understands the risks of Zika and that practices mosquito control at the hotel or resort.
DOUCLEFF: And that has air-conditioning.
HOTEZ: Preferentially central air-conditioning, where you don't have to worry about those box-like air-conditioners that are often porous on the sides to mosquitoes.
DOUCLEFF: Hotez says you can also stop mosquitoes by wearing long sleeves, long pants and socks and by using bug spray. Dr. Karin Nielsen at the University of California Los Angeles says the key is long-acting bug spray. She recommends one with a compound in it called picaridin.
KARIN NIELSEN: There's a lot of experience now with this in Brazil. That's what we're - people are recommending in Brazil for pregnant women. It lasts for about 10 hours.
DOUCLEFF: And it's less toxic than DEET. If you do go with DEET, make sure it has at least 20 percent DEET in it. Then it will last about five hours. And keep using that bug spray when you get home. The CDC's Martin Cetron says many people catch Zika but don't know it. And they could pass it on to mosquitoes back here in the States.
CETRON: Nobody wants to be the one who's introduced Zika virus into their local community.
DOUCLEFF: Or be responsible for starting a whole new outbreak. Michaeleen Doucleff, NPR News. Transcript provided by NPR, Copyright NPR.