American Doctor Tests Positive For Ebola

An American doctor working in Liberia has tested positive for the ebola virus, a US missionary group confirmed.

Serving in Mission (SIM) said the male obstetrician, who was not immediately identified by name, did not work in an ebola ward.

The doctor "immediately isolated himself" upon the onset of symptoms and is "doing well and is in good spirits", the group said in a statement

It was not immediately clear how the doctor contracted the disease.

SIM President Bruce Johnson said the organisation was "surrounding our missionary with prayer".

The case marks the third known American to contract the deadly virus, which has killed more than 1,500 people in Guinea, Liberia, Sierra Leone and Nigeria.

Last month, Dr Kent Brantly and SIM missionary Nancy Writebol were released from hospital in Atlanta, Georgia, after weeks of isolation and treatment.

Both were evacuated from Liberia after testing positive for the virus, which has prompted authorities to cordon off entire towns and led to border closures by neighbouring nations.

On Tuesday, the World Health Organization warned that the outbreak would "get worse before it will get better."

The group's director Margaret Chan said existing treatment centres can offer little more than palliative care and called on other countries to contribute civilian and military medical personnel familiar with biological disasters.

Doctors Without Borders President Joanne Liu said the centres have been "reduced to places where people go to die alone".

Ebola is only spread through direct contact with the bodily fluids of those infected with the virus who are experiencing symptoms.

:: Video has emerged of Liberian ebola clinic workers dressed in contamination suits chasing an escaped patient through the streets after he left a treatment centre to visit a market.