A New York doctor currently being treated for Ebola has received a blood transfusion from a woman who contracted the disease and survived, according to media reports.

CNN reported that Dr. Craig Spencer, who tested positive for the virus on Thursday, received a blood transfusion from Nancy Writebol, an aid worker who contracted the disease in Africa, but survived.

Bellevue hospital in Manhattan, where Spencer is being held in isolation for treatment, said that he received the transfusion on Friday, the network reported.

Writebol was the second American to be treated for Ebola in the United States. She contracted the disease while working for a charity in Africa. Both Writebol and the patient who contracted the virus before her, Dr. Kent Brantly, were treated at Emory Hospital in Atlanta, Georgia, and both survived and are now Ebola-free.

Blood transfusions from survivors of the virus have been used in the past to treat those still suffering from the disease. Ebola patients Ashoka Mukpo and Dr. Rick Sacra, both of whom recovered from the disease, received such treatment, according to a report from NBC News

Dr. Spencer's condition reportedly worsened Saturday, as he suffered the onset of gastrointestinal symptoms. 

According to the WHO, the case fatality rates for Ebola patients in past outbreaks ranged from 25 – 90 percent. Only one patient out of the four American cases in the current outbreak, Thomas Eric Duncan, died as a result of the disease.