A man in Lagos reads a local newspaper with the headline Ebola Virus kills Liberian in Lagos (AP)

Dr Kent Brantly, left, treats an Ebola patient at the Samaritan's Purse Ebola Case Management Centre in Monrovia (AP Photo/Samaritan's Purse)

An American doctor is receiving intensive medical treatment in Liberia after he was infected with the deadly Ebola virus while treating patients in the West African nation, a spokeswoman for an aid organisation said.

Dr Kent Brantly was in a stable condition, talking with his doctors and working on his computer while receiving care at a hospital in the Liberian capital of Monrovia, said Melissa Strickland, a spokeswoman for North Carolina-based Samaritan's Purse.

She cautioned that Dr Brantly is "not out of the woods yet." She said patients have a better chance of survival if they receive treatment immediately after being infected, which Dr Brantly did.

Dr Brantly, 33, has been working with Samaritan's Purse in Liberia since October 2013 as part of the group's post-residency programme for doctors, Ms Strickland said. He is the medical director for the aid organisation's case management centre in the city.

The website for Samaritan's Purse said Dr Brantly had worked as a family practice physician in Fort Worth, Texas.

The highly contagious Ebola virus is one of the most deadly diseases in the world. Photos of Dr Brantly working in Liberia show him in white overalls made of a synthetic material that he wore for hours a day while treating Ebola patients.

Dr Brantly was quoted on the organisation's website earlier this year, discussing efforts to maintain an isolation ward for patients.

"The hospital is taking great effort to be prepared," Dr Brantly said. "In past Ebola outbreaks, many of the casualties have been healthcare workers who contracted the disease through their work caring for infected individuals."

Ms Strickland says that Dr Brantly's wife and children had been living with him in Africa, but they are currently in the US.

A woman who identified herself as Dr Brantly's mother answered a US phone listing for him, but said family members are declining comment at this time.

The deadly disease has killed at least 672 people in several African countries since the outbreak began earlier this year.

A government official said earlier that one of Liberia's most high-profile doctors had died of Ebola, highlighting the risks facing health workers trying to combat the deadly disease.

Dr Samuel Brisbane is the first Liberian doctor to die in the outbreak. A Ugandan doctor working in the country died earlier this month.

PA Media