The World Health Organization on Tuesday authorized the use of experimental drugs in the fight against Ebola as the death toll topped 1,000 and a Spanish priest became the first European to succumb to the virus in the latest outbreak.
The declaration by the UN's health agency came after a US company that makes an experimental serum said it had sent all its available supplies to hard-hit west Africa.
"In the particular circumstances of this outbreak, and provided certain conditions are met... it is ethical to offer unproven interventions with as yet unknown efficacy and adverse effects," the WHO said in a statement following a meeting of medical experts in Geneva.
The current outbreak, described as the worst since Ebola was first discovered four decades ago, has now killed 1,013 people, the WHO said.
Cases have so far been limited to Guinea, Liberia, Sierra Leone and Nigeria, all in west Africa where ill-equipped and fragile health systems are struggling to cope.
An elderly Spanish priest who became infected while helping patients in Liberia died in a Madrid hospital on Tuesday, just five days after being evacuated.
Monrovia said it had requested samples of an experimental drug, ZMapp, that has shown some positive effects on two US aid workers but failed to save the Spanish priest.
Supplies would be brought in by a representative of the US government later this week, the Liberian government said.
There is currently no available cure or vaccine for Ebola, which the WHO has declared a global public health emergency, and the use of experimental drugs has stoked an ethical debate.
- Early phase -
Despite promising results for the ZMapp treatment, made by private US company Mapp Biopharmaceutical, it is still in an early phase of development and had only been tested previously on monkeys.
ZMapp is in very short supply, but its use on the Western aid workers evacuated to the United States last week triggered controversy and demands that it be made available in Africa.
Mapp said it had sent all its available supplies to West Africa.
"In responding to the request received this weekend from a West African nation, the available supply of ZMapp is exhausted," it said in a statement.
"Any decision to use ZMapp must be made by the patients' medical team," it said, adding that the drug was "provided at no cost in all cases."
The company did not reveal which nation received the doses, or how many were sent.
But the Liberian presidency said: "The White House and the United States Food and Drug Administration have approved the request for sample doses of experimental serum to treat Liberian doctors who are currently infected with the deadly Ebola virus disease."
- Price hikes and food shortages -
Panic is stalking the impoverished countries ravaged by the disease in west Africa, where drastic containment measures are causing transport chaos, price hikes and food shortages, and stoking fears that people could die of hunger.
In Liberia -- where Ebola has already claimed more than 300 lives -- a third province was placed under quarantine on Monday.
President Ellen Johnson Sirleaf also banned state officials from traveling abroad for a month and ordered those outside the country to return home within a week.
Guinea, Liberia and Sierra Leone account for the bulk of the cases, but Nigeria, Africa's most populous country, has also counted two deaths.
Numerous countries have imposed emergency measures, including flight bans and improved health screenings.
In Sierra Leone, eight Chinese medical workers who treated patients with Ebola have been placed in quarantine, China's envoy in Freetown said Monday, but would not be drawn on whether they were displaying symptoms of the disease.
In addition, 24 nurses, most from the military hospital in Freetown, have been quarantined, hospital officials said, while a senior physician had contracted Ebola but was responding well to treatment.
The nation's sole virologist, who was at the forefront of its battle against the epidemic, died from Ebola last month.
As countries around the world were on alert, Japan said it was evacuating two dozen staff from Guinea, Liberia and Sierra Leone.