A young girl from Los Angeles County who traveled to El Salvador was infected with the Zika virus, officials said Tuesday. The infection, which usually has no symptoms, worries public health experts because it appears to be linked to a recent spike of a serious birth defect in Brazil. Officials said that travelers should take precautions when visiting other countries, and that some people should postpone their trips abroad.

L.A. County health officials said the girl had traveled to El Salvador in late November, where she probably contracted the illness. She has recovered. Zika is a mosquito-borne illness that, before 2015, occurred only in Africa, Southeast Asia and the Pacific Islands. But last year, an outbreak was reported in Brazil, and cases of the infection have since been detected in 20 countries in the Americas. FULL REPORT