New York Mayor Bill de Blasio hugs Dr. Craig Spencer as he is discharged from Bellevue Hospital, after being stricken by Ebola, in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

New York Mayor Bill de Blasio greets Dr. Craig Spencer as he is discharged from Bellevue Hospital, after being stricken by Ebola, in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

Dr. Laura Evans hugs Dr. Craig Spencer during an announcement of Spencer's discharge from Bellevue Hospital after being declared free of the Ebola virus in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

Dr. Craig Spencer laughs as he speaks in front of New York Mayor Bill de Blasio (R) and Dr. Ram Raju, Health and Hospitals Corporation (HHC) President, during an announcement of his discharge from Bellevue Hospital after being declared free of the Ebola virus in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

Dr. Laura Evans speaks about the care of Dr. Craig Spencer (R) in front of New York Mayor Bill de Blasio (L) during an announcement of Spencer's discharge from Bellevue Hospital after being declared free of the Ebola virus in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

New York Mayor Bill de Blasio walks with Dr. Craig Spencer (R) as he is discharged from Bellevue Hospital, after being declared free of the Ebola virus, in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

New York Mayor Bill de Blasio walks with Dr. Craig Spencer (C) as he is discharged from Bellevue Hospital after being declared free of the Ebola virus in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson 

Dr. Craig Spencer listens to speakers during an announcement of his discharge from Bellevue Hospital after being declared free of the Ebola virus in New York November 11, 2014. A doctor's hospital discharge on Tuesday after weeks of isolation treatment for Ebola was cheered by New Yorkers - from City Hall to the Harlem apartment building where he lives.The release of Dr. Craig Spencer, 33, who worked with Ebola patients in Guinea and had been held at Bellevue Hospital Center since he was diagnosed with the virus on Oct. 23, will mean no one in the United States is being treated for the disease, according to media reports. REUTERS/Lucas Jackson