People who have traveled to regions affected by the Zika virus will be temporarily stopped from donating blood, U.S. health authorities said Wednesday, the latest precaution against an infection that has been tied to birth defect risks in pregnant women.

The Food and Drug Administration is working with other government agencies and with blood collection establishments “to rapidly implement appropriate donor deferral measures for travelers who have visited affected regions in order to protect the blood supply in the United States,” Tara Goodin, a spokeswoman for the agency, said in an e-mail.

Implementing the deferment is still a work in progress, and the FDA declined to say when it would enact the halt on donations. The virus has flared in South and Central America and the Caribbean, and has been tied to birth defects such as microcephaly, or an abnormally small head.