* Spanish priest due to be airlifted out on Wednesday
* 45 new deaths reported in three days to Aug 4
* Many hospitals, clinics have closed amid public panic
* Operation "White Shield" begins in north Liberia (Adds details)
By Derick Snyder and Daniel Flynn
MONROVIA/DAKAR, Aug 6 (Reuters) - 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 a hospital where several staff were infected, including a Spanish priest.
The outbreak of the haemorrhagic fever has overwhelmed rudimentary healthcare systems and prompted the deployment of troops to quarantine the worst-hit areas in the remote border region of Guinea, Liberia and Sierra Leone.
The World Health Organization (WHO) reported 45 new deaths in the three days to Aug. 4. Its experts began an emergency meeting in Geneva on Wednesday to discuss whether the epidemic constitutes a "Public Health Emergency of International Concern" and to consider new measures to contain it, including the possible use of experimental drug treatments.
"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 spread of the disease increased when a U.S. citizen died in Nigeria last month after flying there from Liberia. The health minister said on Wednesday that a Nigerian nurse who had treated the deceased Patrick Sawyer had 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.
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 the bodies of family members onto the streets of Monrovia to avoid quarantine measures.
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.
TROOPS DEPLOYED IN OPERATION "WHITE SHIELD"
Spain's health ministry denied that one of the nuns - born in Equatorial Guinea but holding Spanish nationality - had tested positive for Ebola. The other nun is Congolese.
"We hope they can evacuate us. It would be marvellous, because we know that, if they take us to Spain, at least we will be in good hands," Pajares told CNN in Spanish this week.
Healthcare workers are in the front line of fighting the virus, and two U.S. health workers from Christian medical charity Samaritan's Purse caught the virus in Monrovia and are now receiving treatment in an Atlanta hospital.
The two saw their conditions improve by varying degrees in Liberia after they received an experimental drug, a representative for the charity said.
Three of the world's leading Ebola specialists urged the WHO to offer people in West Africa the chance to take experimental drugs, too, but the agency said it "would not recommend any drug that has not gone through the normal process of licensing and clinical trials".
A spokesman for the Liberian government said it would be willing to allow in-country clinical trials.
Highly contagious, Ebola kills more than half of the people who contract it. Victims suffer from fever, vomiting, diarrhoea and internal and external bleeding.
Many regular hospitals and clinics have been forced to close across Liberia, often because health workers are too afraid of contracting the virus themselves or because of abuse by locals who think the disease is a government conspiracy.
In an effort to control the disease's spread, Liberia has deployed the army to implement controls and isolate severely affected communities, an operation codenamed "White Shield".
The information ministry said on Wednesday that soldiers were being deployed to the isolated, rural counties of Lofa, Bong, Cape Mount and Bomi to set up checkpoints and implement tracing measures on residents suspected of coming into contact with victims.
Neighbouring Sierra Leone said it has implemented new restrictions at the airport and that it was asking passengers to fill in forms and take a temperature test. In the country's east, the military had set up roadblocks to limit access to affected areas, MSF's Lorenzi said.
Some major airlines, such as British Airways and Emirates, have halted flights to affected countries, while many expatriates were getting out, government officials said.
"We've seen international workers leaving the country in numbers," Liberia's Finance Minister Amara Konneh told Reuters.
Randgold Resources - which mines gold in neighbouring Mali and Ivory Coast - advised its workers not to travel to the affected countries.
Both India and Greece advised their citizens on Wednesday against non-essential travel to Guinea, Liberia, Sierra Leone and Nigeria and said they would take extra measures at its entry ports. (Additional reporting by Clair MacDougall in Monrovia, Emma Farge and Daniel Flynn in Dakar, Tim Cocks in Lagos, Paul Day in Madrid and Tom Miles in Geneva; Writing by Emma Farge and Daniel Flynn, editing by Peter Millership, Will Waterman and David Stamp)