(Illustration)
(Illustration)Israel Airport Authority

A New York doctor living in Harlem was diagnosed with Ebola on Thursday, after having returned last week from Guinea where he is thought to have treated patients suffering from the epidemic with Doctors Without Borders.

New York Mayor Bill de Blasio announced on Thursday evening at Bellevue Hospital Center that the tests had come back positive for Dr. Craig Spencer, reports CBS 2.

All four people thought to have had contact with Spencer during the time when he showed symptoms and was in danger of spreading the lethal virus have been quarantined, and officials stressed there is no need to worry, as the virus is only transmitted through direct contact with bodily fluids.

Spencer had used the subway system, riding on the A, L and 1 trains, and likewise taken an Uber taxi ride to go bowling at The Gutter in Williamsburg, Brooklyn, said New York City Health Commissioner Dr. Mary Travis Bassett.

However, she stressed there was virtually no chance of the disease spreading in those locations, as simply being in the same environment is not enough to become infected with the virus.

"We want to state at the outset - there is no reason for New Yorkers to be alarmed,” de Blasio said, announcing "a full coordinated effort that has been working night and day, coordinating city, state and federal resources."

De Blasio added "being on the same subway car, or living near a person with Ebola, does not in itself put someone at risk."

The recent case comes after two scares last week.

In one, a man from Nigeria died vomiting on a plane to JFK Airport; another - outside the Pentagon in Washington, DC - saw a bus of commuters in Virginia evaluated by heath care officials after a woman vomited on board and noted she had recently visited West Africa.

Thomas Eric Duncan of Liberia became the first confirmed case of the disease in America when he visited Dallas, where he died of the disease earlier this month.

Duncan's case can be seen as reassuring in a way for New York, as he did not infect anyone else - other than two Dallas nurses who were treating him and who are currently recovering, meaning that much of the concern in the Big Apple will be on preventing the spread to health care workers, officials said.

"The chances of the average New Yorker contracting Ebola are extremely slim," officials said in a statement Thursday. "Ebola is spread by directly touching the bodily fluids of an infected person. You cannot be infected simply be being near someone who has Ebola."

The disease has already killed roughly 5,000 people in West Africa, with officials saying the actual number including unreported cases may be much higher and may be set to rise. It has shown a 70% mortality rate, higher than its traditional rate of 50%.

Aside from the cases in the US, a UN worker infected with Ebola died last Tuesday after traveling to Liberia to treat the disease. There have also been several cases of infected British nationals recorded in Macedonia to the north of Greece, and a Spanish nurse became the first to contract Ebola outside of West Africa two weeks ago.