GENEVA (AFP) - The World Health Organisation said Thursday that the global death toll from the Ebola virus had increased to 5,689 out of a total of 15,935 cases of infection, mainly in western Africa.

The earlier WHO toll from last Friday gave a death toll of 5,459 and 15,351 cases.

The WHO believes that the number of deaths is likely far higher, given the difficulty in collecting comprehensive figures and with Ebola having a high fatality rate.

The first case discovered in the current outbreak was in Guinea in December 2013.

The deadliest Ebola outbreak ever continues to affect Guinea, Liberia and Sierra Leone the most.

Liberia has been the worst hit of all, though the death rate there appears to be slowing.

"Case incidence is stable in Guinea, stable or declining in Liberia, but may still be increasing in Sierra Leone," the WHO said in its update.

The WHO reported a total of 3,016 Ebola deaths in Liberia out of 7,168 cases.

In Sierra Leone it has logged 1,398 deaths, up from 1,267 previously, and 1,260 deaths have been recorded in Guinea.

In all some 600 new cases were reported in these three worst-hit countries over the previous week.

In Mali, the most recent county in the region hit by Ebola, the WHO spoke of eight confirmed cases, six of which had proved fatal.

The tolls in Nigeria - eight fatalities - and Senegal - one sole case - have remained unchanged for 57 days. Both countries have thus been taken off the danger list.

Ebola, one of the deadliest viruses known to man, is spread only through direct contact with the bodily fluids of an infected person showing symptoms such as fever or vomiting.

People caring for the sick or handling the bodies of people infected Ebola are especially exposed.

Health workers have been among the worst hit, with 340 deaths out of 592 cases.

Outside of Africa, there have been four Ebola cases diagnosed in the United States one of which was fatal.

There has also been one confirmed case in Spain, a nurse who has recovered.