纽约一名医生感染埃博拉

Thirty-three-year-old Dr. Craig Spencer came down with a fever Thursday after returning from Guinea where he worked with the charity Doctors Without Borders, treating Ebola patients.

He is currently being treated at midtown Manhattan's Bellevue Hospital, one of the eight hospitals designated for receiving Ebola patients by US authorities.

New York Mayor Bill de Blasio says there is no reason for New Yorkers to be alarmed.

"Ebola is very difficult to contact. Being in a same subway car or being near an Ebola patient does not put someone at risk. We are working very closely with our state and federal partners to ensure that we protect the health of New Yorkers."

Health experts believe Ebola patients are only contagious when showing clear symptoms of the virus, and the disease is only transmittable through bodily fluids.

New York City health commissioner Dr. Mary Bassett says health workers at Bellevue Hospital are fully prepared.

"The health workers are using full protected gear. They were ready because we knew this patient was being transported. He had a very orderly removal from his home."

Two nurses in Dallas, Texas who treated the first Ebola victim in the U.S. came down with the disease, arousing public debate over the country's public health system.

Some believe government officials have taken too much time to explain response procedures related to the virus.

But New York State Governor Andrew Cuomo says they have learned from what took place in Dallas.

"We are as ready as one could be for this circumstance. What happened in Dallas was exactly the opposite. Dallas was unfortunately caught before they were prepared, before they knew what they were dealing with."

Cuomo also says health officials have identified four close contacts of Dr. Spencer.

His fiancee and two friends have been placed into quarantine.

The fourth person is a car service driver who had no direct contact with him and is not considered at risk.

Over 4,800 people have died of Ebola, over 240 of them health workers.

For CRI, I'm Su Yi in New York.