The British man diagnosed with Ebola said he wanted to "make a difference" by working with those infected with the potentially fatal disease and said he was able to help fight the outbreak despite lacking experience.
William Pooley, 29, became infected in Sierra Leone and has been flown back to Britain, where he is receiving treatment at London's Royal Free Hospital.
He is the first Briton infected in an epidemic that has killed hundreds in west Africa so far.
Pooley's family have thanked doctors fighting to save his life for the "excellent care" he is being given. They said: "We would like to express our thanks to all involved in bringing our son back to the UK.
"We have been astounded by the speed and way which the various international and UK government agencies have worked together to get Will home.
"Will is receiving excellent care at the Royal Free Hospital and we could not ask for him to be in a better place.
"We would like to thank all our family and friends for their best wishes and ask everyone to remember those in other parts of the world suffering with Ebola who do not have access to the same healthcare facilities as Will."
Mr Pooley, who comes from the small village of Eyke in Suffolk, was working at a hospice in the country's capital Freetown but moved to Kenema when he heard that other healthcare workers at KGH had died from Ebola.
Dr Nick Beeching, senior lecturer in infectious diseases at the Liverpool School of Tropical Medicine, said that Mr Pooley is likely to be very "frightened" and one of the first things doctors must do is reassure him.
He told BBC News: "The first priority is just to make sure he remains stable. It sounds as if he is not too badly off, and it is a good thing he has been brought over at an early stage of the infection so he can be given good, supportive care.
"Obviously they will be trying to reassure him. It is quite frightening being in one of these isolators."
In an interview with a blogger for freetownfashpack.com published earlier this month, he is reported to have said: "It's the easiest situation in the world to make a difference.
"I'm not particularly experienced or skilled, but I can do the job and I am actually helping."
He was named by Dr Robert Garry, an American scientist who worked at the same hospital as him in the west Africa country.
There is no cure for Ebola and outbreaks have a fatality rate of up to 90%.
Mr Pooley tested positive for Ebola after treating patients suffering from the virus at Kenema Government Hospital in the south-east of Sierra Leone.
He was airlifted to the UK on a specially equipped C17 Royal Air Force jet, landing at RAF Northolt in west London at 9pm.
He was then transported to the UK's only high level isolation unit at the Royal Free Hospital in Hampstead, north London.
The Department of Health said he was not "seriously unwell". Health chiefs insisted that the risk to the British public from Ebola is "very low".
Dr Garry, of Tulane University in New Orleans, US, has worked at KGH for around a decade on a virus research project.
He said he was told by a university colleague that the test results for Mr Pooley were received in the early hours of Saturday morning.
"They worked as hard as they could, as fast as humanly possible to make these arrangements," he said.
"Of course they were wanting to make sure that he got the best care possible. It was kind of a remarkable turnaround, barely over 24 hours (later) he was heading towards that plane."
Dr Garry paid tribute to Mr Pooley's decision to treat Ebola sufferers.
"It's a very honourable thing. He saw the need. He read about our nurses who were unfortunately dying there and took it on himself to come over and volunteer and learned how to be as safe as he could.
"But when you work hard like that, when you put in so many hours, you're going to make a mistake and unfortunately that seems to have happened in this case.
"I just hope the best for him, that he can get the best treatment he can get.
"He's a young man, he's got a good chance. It was caught early."
Mr Pooley's bed at the Royal Free Hospital is surrounded by a specially-designed tent with its own controlled ventilation system. Only specially-trained medical staff are allowed inside the unit.
Professor John Watson, deputy chief medical officer, insisted that "the overall risk to the public in the UK remains very low".
He said: "We have robust, well-developed and well-tested NHS systems for managing unusual infectious diseases when they arise, supported by a wide range of experts.
"UK hospitals have a proven record of dealing with imported infectious diseases and this patient will be isolated and will receive the best care possible."
Dr Paul Cosford, director for health protection at Public Health England, said protective measures would be strictly maintained to avoid the virus being transmitted to staff transporting the patient and healthcare workers in the UK.
He added: "For Ebola to be transmitted from one person to another contact with blood or other body fluids is needed and as such, the risk to the general population remains very low."
Dr Bob Winter, national clinical director for emergency preparedness and critical care for NHS England, said preparations have been made over the past few weeks to ensure any patient being repatriated to the UK receives the best possible care.
Professor David Heymann, the director of the Chatham House Centre on Global Health Security, said Ebola is spread through sweat, blood and vomit, but is not airborne.
This, combined with the hospital's strict measures, means there is no chance the infection will spread to staff, patients or visitors.
He said: "The good thing, if there is a good thing about Ebola, it does not spread by respiratory means.
"That means that isolation is a little bit easier than having to protect also against airborne transmission. It is only transmitted by body secretions and by blood, and by vomit and excrement.
"That person will be put under strict isolation measures. Hospital workers will be completely protected so there is no possibility of them getting infected themselves, or indeed transmitting the infection unintentionally to others in the hospital."
He said Mr Pooley's chances of survival depended on a range of factors including his fitness and how well his body naturally produces antibodies to fight it off.