Dr. Craig Spencer, who recently returned from Guinea, has tested positive for the Ebola virus, making him New York City's first diagnosed patient.
Spencer, 33, was taken to Bellevue Hospital on Thursday after reporting a "fever and gastrointestinal symptoms," city officials said in a statement.
A preliminary test confirms that the doctor contracted the deadly Ebola virus. Another test will be conducted by the Centers for Disease Control.
Doctors Without Borders, with whom he had been participating in treating the virus in Africa, confirmed that one of its own contracted Ebola yesterday:
"A person in New York City, who recently worked with Doctors Without Borders in one of the Ebola-affected countries in West Africa, notified our office this morning to report having developed a fever."
"As per specific guidelines Doctors Without Borders provides its staff on return from Ebola assignments, the individual engaged in regular health monitoring and reported this development immediately."
New York health officials are currently working to track down who Spencer may have had contact with since returning to the United States October 14.
At a press conference, Mayor Bill de Blasio said that the doctor is cooperating with officials to help them reconstruct his activities over the past few days.
According to a rough timeline provided by city officials, Spencer's symptoms developed Wednesday, prompting him to isolate himself in his apartment.
When he felt worse Thursday, he and his fiancée made a joint call to authorities to detail his symptoms and his travels. EMTs in full Ebola gear arrived.
One potential concern? Spencer took the subway from Manhattan into Brooklyn on Wednesday night, just a day before he reported a fever from the virus.
There, the "dedicated humanitarian" went to a bowling alley, then took a cab home. His Harlem apartment on West 147th Street has since been sealed off.
The international ER doctor works at New York-Presbyterian/Columbia University Medical Center. He had not seen any patients or been to the hospital since his return.
Spencer "went to an area of medical crisis to help a desperately underserved population. He is a committed and responsible physician who always puts his patients first."