The New York Times reported Thursday that a New York doctor is sick with the Ebola virus. Doctor Craig Spencer recently returned from treating Ebola patients in Guinea in the West Africa region. Spencer was sent to Bellevue Hospital Center and put in isolation while investigators attempt to trace every step he had taken the last few days.

New York Mayor Bill de Blasio and Gov. Andrew Cuomo said residents should not be alarmed by Spencer’s diagnosis, even as the doctor was seen riding the subway, taking a cab and bowling since he returned to the U.S. a week ago, according to the Associated Press.

“We want to state that 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 NY Times also reported that at least three people Spencer had contact with this week have been placed in isolation. The Centers for Disease Control and Prevention dispatched a team to New York and is conducting its own test to confirm Spencer’s positive test, which was performed by a New York City lab.