NEW YORK (AP) — A Doctors Without Borders physician who recently returned to the city after treating Ebola patients in West Africa was being tested Thursday for the virus.

Mayor Bill de Blasio said results could come late Thursday.

The doctor, who returned from Guinea more than a week ago and was monitoring his own health, was rushed by ambulance to Manhattan’s Bellevue Hospital, a designated Ebola center, after reporting he had a 103-degree fever and diarrhea, city officials said.

“We can safely say that it is a very brief period of time that patient has had symptoms,” the mayor said in a news conference. “Our understanding is that very few people were in direct contact with him.”

Ebola, which is spread through contact with an infected person’s bodily fluids, has killed thousands of people in Africa. Only three people have been diagnosed in the U.S., and one has died: a Liberian man in Dallas.

De Blasio said the doctor was in good shape and has described in great detail where he was in the last few days and with whom he had contact.

The doctor acknowledged riding the subway and taking a cab to a Brooklyn bowling alley in the past week before he started showing symptoms, according to a senior city official who spoke to The Associated Press on condition of anonymity because he was not authorized to the discuss the details publicly.

According to a rough timeline provided by the official, the doctor’s symptoms developed Wednesday, prompting him to isolate himself in his Harlem apartment. When he felt worse Thursday, he and his fiancé made a joint call to authorities to detail his symptoms and his travels. EMTs in full Ebola gear arrived and took him to Bellevue in an ambulance surrounded by police squad cars.

“As per the specific guidelines that Doctors Without Borders provides its staff on their return from Ebola assignments, the individual engaged in regular health monitoring and reported this development immediately,” the international humanitarian organization said in a statement.

As of Oct. 14, the organization said 16 staff members have been infected and nine have died.

New York-Presbyterian/Columbia University Medical Center said the doctor was on its staff but had not been to work there since returning from Africa.

“He is a committed and responsible physician who always puts his patients first,” it said in a statement. “Our thoughts are with him, and we wish him all the best at this time.”

Health officials say the chances of the average New Yorker contracting Ebola are slim. Someone can’t be infected just by being near someone who’s sick with Ebola.

Bellevue Hospital has been designated the city’s main venue for handling Ebola cases. It has dozens of staff members at the ready and four isolation rooms that can quickly expand to 20 if needed.