Pregnant Women Advised Not to Travel to 11 Southeast Asian Countries Over Zika Risk

U.S. health officials on Thursday advised pregnant women to avoid nonessential travel to Southeast Asia and the Maldives because of the potential risk of Zika infection, which can cause severe birth defects.

The U.S. Centers for Disease Control (CDC) singled out 11 countries in its latest advisory: Brunei, Burma (Myanmar), Cambodia, Indonesia, Laos, Malaysia, Maldives, Philippines, Thailand, Timor-Leste (East Timor) and Vietnam.

Thursday’s advisory about potential risks in Southeast Asia so far only recommend postponing nonessential travel. The CDC said travelers have been infected with the virus in parts of Southeast Asia, where Zika is endemic and has been present for many years. Many local residents are believed to be immune, though travelers most likely are not.

Read More: Why You Should Care About Zika

“Pregnant women traveling to Southeast Asia could become infected with Zika virus,” the CDC said. “The level of this risk is unknown and likely lower than in areas where Zika virus is newly introduced and spreading widely.”

Zika is a primarily a mosquito-borne disease, but it can also be sexually transmitted. It was identified in Brazil last year and has since spread globally. Infection is not always symptomatic, but can cause a fever similar to dengue. Zika infection during pregnancy can cause serious brain abnormalities such as microcephaly and other birth defects.

Read More: See All the Places Where the Zika Virus Has Spread

The CDC has advised pregnant women to avoid almost 60 countries or regions worldwide because of Zika’s rapid spread.