DALLAS - The Texan nurse diagnosed with Ebola has received a blood transfusion from survivor Dr Kent Brantly, said reports.
Ms Nina Pham, 26, is now clinically stable.
Reports which quoted her priest Father Jim Khoi said Ms Pham has received a blood transfusion from a person who has survived an Ebola infection.
Britain's Daily Mail identified the survivor as Dr Brantly, who was flown back from Liberia to the United States after contracting Ebola during his missionary work for aid group Samaritan’s Purse.
He survived after receiving a dose of the experimental serum Z-Mapp. He also received a blood transfusion from a 14-year-old Ebola survivor, according to Samaritan’s Purse.
Those who have survived Ebola have antibodies in their blood which some experts believe can help new sufferers beat the disease. Some early research suggests using blood from survivors could work. In 1995, during an outbreak in Kikwit, Congo, seven of eight infected people given the therapy survived during an outbreak with an 80 per cent fatality rate. Bloomberg News reported earlier.
Ms Pham became the first person to contract Ebola in the United States while caring for dying Liberian patient Thomas Eric Duncan.
The Daily Mail reported that Ms Pham is from a Vietnamese family, and that her uncle, Mr Jason Nguyen, had confirmed that she is the one who contracted Ebola while treating Mr Duncan.
The report quoted Mr Nguyen as saying: "My sister (Nina's mother) is very upset. We all are. She said she was going up to the hospital in Dallas and I haven't heard from her since. I've tried to all but I can't get through. It's very shocking.
"Nina is very hard working. She is always up at the hospital in Dallas."
The family was in shock when it learned the young woman had contracted Ebola, said Tom Ha, a close friend of the Pham family who is also a Bible studies teacher at the Our Lady of Fatima Catholic Church in Fort Worth.
"The mother was crying, very upset," he told Reuters.
Dr Thomas Frieden, director of the US Centers for Disease Control and Prevention, said health authorities are still investigating how Ms Pham became infected while caring for Duncan in an isolation ward at Texas Health Presbyterian Hospital. Ms Pham is "clinically stable", Dr Frieden said, and the CDC is monitoring others involved in Duncan's care in case they show symptoms of the virus.
"We have to rethink the way we address Ebola infection control. Even a single infection is unacceptable," Frieden told reporters. "The care of Ebola is hard. We're working to make it safer and easier."
He also apologised for remarks on Sunday, when Ms Pham's infection was first disclosed, that suggested she was responsible for a breach in protocols that exposed her to the virus. Some health-care experts said the comments failed to address deep gaps in training hospital staff to deal with Ebola.
"I'm sorry if that was the impression given," Dr Frieden said. He said the agency would take steps to increase the awareness of Ebola at the nation's hospitals and training for staff.
Ms Pham graduated from the four-year nursing degree programme at Texas Christian University in 2010, NBC News quoted a spokesman for the school as saying.
According to the school's website, it teaches nurses to be “liaisons among doctors, patients and other members of the health care team”. It made no mention of handling dangerous diseases.
Ms Pham got her certificate in Critical Care Nursing on Aug 1, less than two months ago before Mr Duncan arrived in hospital with Ebola, reported NBC News.
A critical care nurse handles “life-threatening problems”, and patients who are “vulnerable, unstable and complex, thereby requiring intense and vigilant nursing care", according to the website of the American Association of Critical Care Nurses.
US President Barack Obama met Dr Frieden and senior members of his administration later on Monday to discuss ways to ensure the country's health-care system was prepared to care for people with the virus, the White House said.
Mr Obama was briefed about the second Dallas case and stressed that "lessons learned" from the CDC's investigation should be shared with hospitals and health-care workers across the country, the White House said.
He also spoke separately with UN Secretary-General Ban Ki Moon and with French President Francois Hollande about international efforts to contain the outbreak and to provide treatment centres in affected African nations.
Meanwhile, Louisiana's top law enforcement official said he would file a temporary restraining order to prevent the personal items of Mr Duncan, who died on Wednesday, from being buried in a local landfill, even after being incinerated.
Louisiana Attorney General Buddy Caldwell said material collected from Mr Duncan and the Dallas apartment where he was staying was taken to Port Arthur, Texas, on Friday to be processed at the Veolia Environmental Services incinerator. From there the incinerated material would go to a hazardous waste landfill in Louisiana.
"There are too many unknowns at this point, and it is absurd to transport potentially hazardous Ebola waste across state lines," Caldwell said in a statement. According to CDC guidelines, the Ebola virus does not survive on materials that have been incinerated.
The current Ebola outbreak is the worst on record and has killed more than 4,000 people, mostly in West Africa's Liberia, Sierra Leone and Guinea.
Mr Duncan was exposed to Ebola in his home country and developed the disease while visiting the United States.
Ebola, which can cause fever, vomiting and diarrhoea, spreads through contact with bodily fluids such as blood or saliva.
The infection of Ms Pham is the second known to have occurred outside West Africa since the outbreak that began in March. It follows that of a nurse's aide in Spain who helped treat a missionary from Sierra Leone, who died of the virus.
Officials said Ms Pham's pet dog, a one-year-old King Charles Spaniel named Bentley, would be kept safe while its owner was in the hospital.
That contrasts with the dog of the health worker in Spain that was euthanised out of fear the animal could spread the disease, prompting protests from animal rights activists.
With additional information from Reuters