A physician with Doctors who returned to NY City after treating Ebola victims in West Africa. And he tested positive for the virus on Thursday, setting off fresh fears about the spread of the ebola disease.

Mayor Bill de Blasio sought to reassure New Yorkers they are safe from Ebola virus, even as officials disclosed that Dr. Craig r had traveled around the city on subways, taken a taxi and visited a bowling alley in the period between returning from Guinea and developing symptoms.

Spencer, 33, who returned to the US on October 17,  had been taking his temperature twice daily as a precaution to watch for any Ebola virus symptoms, and first developed a fever on Thursday morning, officials said, stressingthat without symptoms, he was not contagious.