NEW YORK — A doctor who became New York City’s first Ebola patient was praised for getting treatment immediately upon showing symptoms, and health officials stressed that the nation’s most populous city need not fear his wide-ranging travel in the days before his illness began.

Mayor Bill de Blasio and Gov. Andrew Cuomo urged residents not to be alarmed by the doctor’s diagnosis Thursday, even as they described him riding the subway, taking a cab and bowling since returning to New York from Guinea a week ago. De Blasio said all city officials followed “clear and strong” protocols in their handling and treatment of him.

“We want to state at the outset that New Yorkers have no reason to be alarmed,” de Blasio said. “New Yorkers who have not been exposed are not at all at risk.”

The doctor, Craig Spencer, a member of Doctors Without Borders, reported Thursday morning coming down with a 100.3-degree fever and diarrhea. He was being treated in an isolation ward at Manhattan’s Bellevue Hospital, a designated Ebola center.