The head of a treatment center in Liberia, the country worst-hit by West Africa's deadly Ebola outbreak, has urged survivors of the disease to donate their blood for use in treating infected patients.

The epidemic has already killed over 2,800 people — more than the combined total of all previous Ebola outbreaks —most of them in Guinea, Liberia and Sierra Leone, where it has overwhelmed already fragile health services.

"We need survivors to come and help us with blood donations," said Attai Omoruto, the Ugandan doctor in charge of the newly opened, 150-bed Island Clinic in Liberia's capital Monrovia.