WASHINGTON (AP) — He’s traveled to the sites of worrisome outbreaks of SARS, bird flu, MERS. But the Ebola outbreak that’s spiraled out of control in West Africa presents new challenges for even a veteran infectious disease doctor — starting with how to stay safe.

“You don’t have to be exhausted to make a small mistake” with protective gear, warned Dr. Daniel Lucey of Georgetown University Medical Center, who recently returned from three weeks in Sierra Leone, where he saw Ebola for the first time.