The Centers for Disease Control and Prevention issued a special travel advisory Tuesday for pregnant women — and those trying to get pregnant.
They should "consider postponing nonessential travel" to 11 countries, the agency says. These countries include Brunei, Cambodia, Indonesia, Laos, Malaysia, the Maldives, Myanmar, Philippines, Thailand, East Timor and Vietnam.
For Singapore, pregnant women "should not travel" there, the CDC says.
The agency has a stronger warning for Singapore compared to the rest of the region because Singapore is currently experiencing a large Zika outbreak. About 400 people have been diagnosed with virus since the end of the August.
Zika was first detected in Southeast back in the 1960's. And scientists think the virus has been circulating throughout the region since then.
"Several countries have reported occasional cases or small outbreaks of Zika," says the CDC's Dr. Denise Jamieson.
But then in the past month, health officials have started to detect more Zika cases around the region. Besides the outbreak in Singapore, cases have cropped up Thailand, the Philippines and Indonesia. Thailand is currently investigating cases of microcephaly to see if they're linked to Zika infection, the World Health Organization said Thursday.
"Although we believe the level of risk for Zika virus infection in Southeast Asia is likely lower than in Latin America — where the virus is spreading widely — we still feel there is some risk to pregnant women in Southeast Asia," Jamieson says.
The strain of Zika circulating in Latin America and the Caribbean is known to cause severe birth defects, including babies born with very small heads and brain damage.
Although the strain in Southeast Asia is slightly different than the one in Latin America, many scientists think the Asian strain will likely be just as dangerous to developing fetuses.
If pregnant women must travel to Southeast Asia, they should discuss the trip with their doctors. And while there, they should take strict precautions to prevent getting bitten by mosquitoes, the CDC says.
When they return from any region with Zika, pregnant women should get tested for the virus, whether they have symptoms or not.
Both men and women should wait six months after returning from Zika regions before trying to get pregnant, the World Health Organization says. They should also practice safe sex to prevent spreading the virus through sexual transmission.
"Sex includes vaginal, anal, and oral sex," the CDC says.
RENEE MONTAGNE, HOST:
Health officials just issued a new travel warning for Southeast Asia. The Centers for Disease Control and Prevention suggests pregnant women and those trying to get pregnant should consider postponing trips to 11 countries in Southeast Asia because of the Zika virus. NPR's Michaeleen Doucleff explains why the CDC is now concerned about that region and what pregnant women's partners should do if they need to travel there.
MICHAELEEN DOUCLEFF, BYLINE: For months now, the CDC has been telling pregnant women not to travel to places where the Zika virus is actively circulating - that's in Central America, South America and the Caribbean - because Zika can cause severe birth defects. But for Southeast Asia, the CDC's new warning is not as strong. They're telling women to seriously consider canceling a trip and to talk to their doctors if they have to go. The CDC's Dr. Denise Jamieson says the softer warning is because Zika isn't as common in Southeast Asia as it is in Latin America.
DENISE JAMIESON: Although we believe the level of risk for Zika virus infection is likely lower in Southeast Asian countries, we still feel there is some risk to pregnant women.
DOUCLEFF: Scientists first detected Zika in Southeast Asia back in the 1960s. Since then, it's been hiding out across the region and causing small outbreaks every now and then. But in the past few months, something has changed. Jamieson says health officials have started detecting more and more cases in the region. Singapore is fighting an outbreak with nearly 400 people infected, and Thailand is investigating a few cases of birth defects possibly linked to Zika. Jamieson says the CDC isn't sure why there's been this Zika surge in Southeast Asia.
JAMIESON: It could be that there's more attention paid to Zika virus by public health authorities, and they're doing additional testing, and people are more aware. It also could be that there is a real increase in transmission consistent with an outbreak.
DOUCLEFF: So the CDC is being cautious. Jamieson says pregnant women who have traveled to Southeast Asia should get tested for Zika when they get home, even if they don't have symptoms. If their partners have been to the area, they should practice safe sex or abstain for six months to keep from passing the virus that way. And when in doubt, check out the CDC's website before you take a trip. Travel guidelines for Zika get updated frequently.
Michaeleen Doucleff, NPR News. Transcript provided by NPR, Copyright NPR.