Health officials have warned pregnant women to avoid travel to the more than 45 countries and territories in which the Zika virus is circulating. Infection during pregnancy can lead to birth defects in infants, particularly brain damage and abnormally small heads, called microcephaly.
But with the Olympics nearing and summer tourism in full swing, what about other travelers? What are the risks of visiting a Zika-affected country for a woman who has no plans to get pregnant — or her partner, or her child? Here are some answers to commonly asked questions.
Where is the Zika virus spreading?
Most of Latin America and the Caribbean. The Centers for Disease Control and Prevention maintains a list of affected countries. But the tally has been criticized for tarring many nations too broadly: Not every region in every country has seen Zika infections.
In particular, the yellow-fever mosquitoes that carry the virus don’t survive at elevations higher than 6,500 feet. So if your plan is to visit Mexico City or go mountain-climbing in Argentina, the odds of being bitten there are close to nil.
Sadly, there’s no easy way to judge the risk of infection region by region. And even if you’re headed to a high-altitude destination in Latin America or the Caribbean, the C.D.C. has warned, you may be at risk of mosquito bites if you fly in or out of an airport below 6,500 feet in elevation.
The travel situation will become more complicated if locally transmitted cases are discovered in the continental United States. As of Friday afternoon, two possible cases are under investigation in Florida.
All travelers can reduce the likelihood of getting mosquito bites by using insect repellents with DEET, picaridin or IR3535, and by booking accommodations with air-conditioning. (Those heading to Brazil might want to check out the military-grade repellent available there.) Wear long-sleeved shirts and pants as often as possible.
What do women need to consider?
Just to reiterate: Women who are pregnant or planning to become pregnant soon should stay away from any country in which the Zika virus is circulating. Don’t even think about it.
Zika infection is usually mild, and most people don’t realize they had it. Roughly 20 percent of infected adults have symptoms such as rash, fever, joint pain or red eyes for up to a week — a nuisance on vacation, but not worse than other hazards.
Women in their childbearing years who are not pregnant and do not plan to become pregnant — and consistently use birth control, ensuring that they will not conceive — can safely visit countries in which the Zika virus is circulating. The same is true for women past their childbearing years.
What about men?
Zika virus can remain in semen for months, even in men who had very mild infections. This month, French scientists reported they had detected the virus in the semen of a 27-year-old man 93 days after he first reported symptoms.
To avoid infecting a sexual partner, a man who experienced symptoms of infection during a trip to a country in which Zika is circulating, or after returning, must use condoms during oral, anal or vaginal sex for six months.
If he did not experience symptoms, he should use condoms for at least eight weeks. If his partner is a pregnant woman, the couple must use condoms for the duration of the pregnancy or abstain from sex altogether.
The Zika virus can be passed between men during anal sex, so advice regarding condom use applies to gay and bisexual men, too.
Some men who must travel and who want to become fathers in the near term — including a few Olympic participants — have taken to freezing their sperm before departing for Zika-affected countries.
What if a man isn’t planning become a father in the next year?
About half the pregnancies in the United States are unintended. If there’s even a remote chance a man’s partner may become pregnant, he should follow the rules above.
Can women give Zika virus to their sexual partners?
Yes. Earlier this month, New York City reported the first documented case of sexual transmission of Zika from a woman to a man. But there are no official recommendations yet for female travelers who might pass on an infection.
No cases of sexual transmission between women have been reported. But whenever a female partner is pregnant or could become pregnant, the C.D.C advises condoms or other barrier methods be used.
Do travelers have to worry about other consequences of Zika infection?
One concern, though very uncommon, is a form of temporary paralysis called Guillain-Barré syndrome. It can leave patients unable to move and dependent on life support.
The rate among those infected with the Zika virus is about 1 in 4,000, research has shown.
Other vacation misfortunes are far more likely, and in itself, the possibility of Guillain-Barré is not a reason to avoid travel.
Do children have anything to fear if they catch Zika virus?
Most school-age children and teenagers who get Zika virus have no symptoms or only mild ones, much like adults. But there are exceptions.
Earlier this year, Colombian doctors reported that a teenager died from complications of sickle cell disease after getting a Zika infection and blood transfusions. It’s not clear why. Still, deaths from Zika infection appear to be rare at any age.
Is there a treatment or vaccine for Zika virus?
No. That’s why the C.D.C. wants pregnant Americans to avoid unnecessary travel to Zika-affected places and for everyone else to take precautions. More than 1,400 travel-associated cases have been reported in the continental United States as of July 20.