There is a need for renewed vigilance over the Ebola epidemic and caution over claims it is retreating, experts have said.
The warning follows an announcement by World Health Organization (WHO) that data from funeral directors and treatment centres indicated lower admission rates and burials in Liberia, the nation hit hardest by the killer virus.
But international aid agency Doctors Without Borders said the slowdown could be due to sick people not being picked up because of a lack of ambulances and so they were being omitted from the statistics.
The charity, known by its French initials MSF, said "mandatory cremation of dead bodies and a poor ambulance and referral system could also be reasons for this decrease in admissions".
"It is too soon to draw conclusions on the reduction of Ebola cases in Monrovia," Fasil Tezera, MSF head of mission in Liberia, said in a statement.
WHO assistant director-general Bruce Aylward told reporters in Geneva on Wednesday that labs were seeing a "plateauing or slight decline" in the number of confirmed cases -- but warned that the crisis was far from over.
Liberia welcomed the possibility of a turning-point in the outbreak but echoed the call for caution issued by the WHO and MSF.
Deputy health minister Tolbert Nyensuah said that even if it managed to achieve no new cases, Liberia would not be able to consider itself Ebola-free until neighbours Guinea and Sierra Leone had eradicated the virus.
The outbreak has claimed almost 5,000 lives, according to the WHO -- almost all in Liberia, Guinea and Sierra Leone -- while the number of cases registered worldwide has soared to 13,703.
- Economies 'devastated' -
World Bank President Jim Yong Kim announced the $100-million (80-million-euro) donation, describing it as a "first down payment", as he visited the UN Mission on Ebola Emergency Response headquarters in Ghana.
"We have to end this epidemic, there's just no other way around it. We've got to get to zero," he said, admitting the world had reacted too slowly and describing the economies of the three worst-hit countries as "devastated".
The outbreak has taken a huge toll on health workers in the region, with 272 deaths, most of them in Liberia and Sierra Leone.
US nurse Kaci Hickox, who recently returned from Sierra Leone, has vowed to fight an order by the state of Maine to remain at home for the final 12 days of her 21-day quarantine period.
A British navy ship arrived in the country's capital Freetown on Thursday laden with 350 personnel and equipment to treat victims of the deadly virus.
"There was lots of anxiety from us as well as from our relatives and loved-ones about coming to Sierra Leone to fight the Ebola virus," Commander Ross Spooner, from Royal Naval Air Station Culdrose, told AFP.
"We have taken all precautions and understood the situation. Berthing in Freetown today, the mood of the personnel is one of a desire to get started on the job and to see that Ebola is kicked out."
Samantha Power, the US envoy to the UN said west Africa is showing "the first tangible signs" that Ebola will be beaten, after she completed a tour of the region this week.
- Malaria threat -
Though there are "alarming gaps in our collective response", foreign aid and a stronger local response were beginning to make a difference, Power said.
But the virus continues to spread fear as far away as east Asia, with China particularly "vulnerable" to an outbreak, according to Ebola co-discoverer Peter Piot, due to soaring economic migration to Africa.
The Philippines has urged hundreds of its citizens to leave Ebola-hit west African nations, as it announced anyone who returned would be placed under a 21-day quarantine.
Further east, North Korea said it intended to quarantine all foreigners entering the country for 21 days, no matter what their country of origin.
While the outbreak is inspiring fear across the world, it is also devastating the response to other deadly diseases at its epicentre, where healthcare systems are said to have collapsed.
MSF warned that Ebola had made obtaining treatment for malaria almost impossible in Liberia, with the majority of general wards closed because staff are too afraid to work.
MSF has begun distributing anti-malarials to around 300,000 people in the city's poorest, most densely-inhabited neighbourhoods.
"The objective is also to eliminate the risk that patients with fever, suspected of having Ebola, will end up in Ebola treatment centres in contact with infected persons," said Chibuzo Okonta, MSF's deputy director of emergency programmes.
Malaria remains the leading cause of death in Liberia, with 1.7 million cases in 2012 according to the health ministry, 1,800 of them fatal.