Members of a UNICEF supported social mobilization team walk on a street carrying posters with information on the symptoms of Ebola virus disease (EVD) and the best practices to help prevent its spread in Freetown, Sierra Leone, in this August 2014 handout photo provided by UNICEF on August 6, 2014. [Photo/Agencies]

MONROVIA/DAKAR - 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 Organisation (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 US charity workers infected in Liberia.

With West Africa's rudimentary healthcare 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.

WHO experts began a two-day crisis meeting in Geneva to discuss whether the epidemic constitutes a "Public Health Emergency of International Concern" and to consider steps to help overstretched emergency organisations.

"This outbreak is unprecedented and out of control," said Walter Lorenzi, head of medical charity Medecins Sans Frontieres (MSF) in Sierra Leone. "We have a desperate need for other actors on the ground - not in offices or in meetings - but with their rubber gloves on, in the field."

International alarm at the diffusion of the virus increased when a US citizen died in Nigeria last month after flying there from Liberia. Authorities said on Wednesday that a Nigerian nurse who had treated Patrick Sawyer had also died of Ebola, and five other people were being treated in an isolation ward in Lagos, Africa's largest city.

With doctors on strike, Lagos health commissioner Jide Idris said volunteers were urgently needed to track 70 people who came into contact with Sawyer. Only 27 have so far been traced.

"We have a national emergency, indeed the world is at risk," Nigeria's Health Minister Onyebuchi Chukwu said after a weekly cabinet meeting in Abuja. "Nobody is immune. The experience in Nigeria has alerted the world that it takes just one individual to travel by air to a place to begin an outbreak."

In Saudi Arabia, a man suspected of contracting Ebola during a recent business trip to Sierra Leone also died early on Wednesday in Jeddah, the Health Ministry said. Saudi Arabia has already suspended pilgrimage visas from West African countries, which could prevent those hoping to visit Mecca for the haj in early October.

Liberia, where the death toll is rising fastest, is struggling to cope. Many residents are panicking, in some cases casting out bodies onto the streets of Monrovia to avoid quarantine measures, officials said.

Beneath heavy rain, ambulance sirens wailed through the otherwise quiet streets of Monrovia on Wednesday as residents heeded a government request to stay at home for three days of fasting and prayers.

"Everyone is afraid of Ebola. You cannot tell who has Ebola or not. Ebola is not like a cut mark that you can see and run," said Sarah Wehyee as she stocked up on food at the local market in Paynesville, an eastern suburb of Monrovia.

St. Joseph's Catholic hospital was shut down after the Cameroonian hospital director died from Ebola, authorities said. Six staff subsequently tested positive for the disease, including two nuns and 75-year-old Spanish priest Miguel Pajares, who is due to be repatriated by a special medical aircraft on Wednesday. \

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