Atlanta (CNN) - It's a lapse that has Americans concerned and health officials asking how it could happen.
A man who had Ebola but didn't know it walked into a Dallas emergency room September 26. Although his symptoms could have indicated Ebola among other things, no one at the hospital asked him if he had recently traveled, a source close to the case told CNN.
The man, who had just flown from Liberia to the States didn't offer the information either, the source said, and the man left the hospital. A spokesman for Texas Health Presbyterian Hospital says it's investigating whether he was questioned.
Regardless, two days passed between the time the man left and then returned to the facility September 28 where it was determined he likely had Ebola and was isolated. He tested positive Tuesday, health officials said.
The CDC advises that all medical facilities should ask for patients with symptoms consistent with Ebola for their travel history. It's possible others were infected because of the lapse.