Health workers in West Africa appealed on Wednesday for urgent help in controlling the world's worst Ebola outbreak as the death toll climbed to 932 and Liberia shut down a major hospital where several staff were infected, including a Spanish priest.

The World Health Organization (WHO) said it would ask medical ethics experts to explore the emergency use of experimental treatments to tackle the highly contagious disease after a trial drug was given to two U.S. charity workers infected in Liberia.

With West Africa's rudimentary health care systems swamped, 45 new deaths from Ebola were reported in the three days to Aug. 4, the WHO said. Liberia and Sierra Leone have deployed troops in the worst-hit areas in their remote border region to try to stem the spread of the virus, for which there is no known cure.