A two-week lockdown has been imposed in a remote area of Kono district of Sierra Leone after bodies were found piled up in the only hospital in the region bordering Guinea.

The discovery has sparked fears of unreported cases of Ebola from the region where the epidemic was thought to be largely under control.

Only essential vehicles were being allowed in and out of the region where a night-time curfew has been clamped, reports Reuters.

Authorities are rushing to build a treatment centre in the district which has only one ambulance to transport the sick and blood samples.

The current Ebola outbreak has killed 6,533 people in the three West African countries of Sierra Leone, Liberia and Guinea and infected 18,118 people, the World Health Organization said.

Sierra Leone has reported the highest number of Ebola cases - 7,897 since the beginning of the outbreak. With poor pay and working conditions compounding a shortage of treatment centres and trained staff, Sierra Leone has overtaken Liberia as the worst affected nation.

The death of a tenth doctor has triggered alarm among the medical fraternity in the country, where the outbreak started, with just two doctors for every 100,000 people.

In Liberia, medical charity Medecins Sans Frontieres was withdrawing from northern Lofa County, a former Ebola hotspot, after no new patients were recorded at its treatment centre in Foya since 30 October.