More than 7,370 people have now died from the Ebola virus, almost all of them in west Africa.

The World Health Organisation reports that as of December 16, there had been 19,031 cases of infection from the deadly virus in Guinea, Liberia and Sierra Leone, of which 7,373 people had died.

The death toll in other countries remained the same: six in Mali, one in the United States, and eight in Nigeria, which was declared Ebola-free in October.

Spain and Senegal, which have both been declared free from Ebola, meanwhile counted one case each, but no deaths.

Sierra Leone, which overtook Liberia as the nation with the most infections, counted 8,759 cases and 2,477 deaths on December 16.

Liberia, long the hardest-hit country, has meanwhile seen a clear decrease in transmission over the past month.

The latest WHO tally saw the country with 7,819 cases and 3,346 deaths, up from the 7,797 infections and 3,290 deaths recorded in the previous update.

In Guinea, where the outbreak started a year ago, 2,453 Ebola cases and 1,550 deaths were recorded as of December 16.

The previous totals showed the country with 2,416 Ebola cases and 1,525 deaths.

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.

WHO's latest figures show a total of 649 healthcare workers were known to have contracted the virus, and 365 of them had died.