The Ebola virus outbreak that's ravaging West Africa probably started with a single infected person, a new genetic analysis shows. This West African variant can be traced genetically to a single introduction, perhaps a person infected by a bat, researchers report in the journal Science.

A man is being treated in isolation in Hawaii for what health officials say is a potential Ebola case, local ABC affiliate KITV reported Thursday, though he could be sick with some other ailment. Authorities stress that they are being especially cautious amid concerns over the deadly virus, two days after the first confirmed case in the United States was identified in Texas.