There has been a "turning point" in the Ebola crisis, with cases falling in the three affected countries, officials of the World Health Organization have revealed.

According to the WHO, just eight cases were detected in Liberia in the last week down from a peak of 500-a-week in September. Guinea and Sierra Leone have also seen falls.

The figures have been described as "most promising" since the outbreak started.

The largest outbreak of Ebola in human history has infected 21,724 people and killed 8,641 - largely in just three countries, Sierra Leone, Liberia and Guinea.

Dr Christopher Dye, the director of strategy in the office of the director general, told the BBC that “the incidence is pretty clearly going down in all three countries now.

"Each of the last three weeks has been the most promising we've seen so far, the message is reductions in all places.

"I would have identified the turning point as the beginning of the decline, first in Liberia and then later in Sierra Leone and Guinea."

Resurgence

However, he argued there was "no basis for complacency" due to the risk of a resurgence in cases.

It is also uncertain whether the downward trends will continue unless there are improvements in "contact tracing".

A single case is enough to start an entire outbreak so identifying everyone who comes into contact with Ebola is vital.