Senegal's decision to close its land border with Guinea, announced by the interior ministry Thursday, is part of intensifying efforts to contain the outbreak that has killed 1,350 people since March in Guinea, Liberia, Nigeria and Sierra Leone.
David Nabarro, a British physician who the United Nations appointed last week to coordinate the global response to the crisis, arrived in west Africa on a mission to revitalise the health sectors of affected countries.
"We're either close to a plateau, but then we'll drop, or we're in a phase -- an inflexion point -- where it is going to increase, and I absolutely cannot tell," Nabarro told AFP during a stopover at Conakry airport en route to the Liberian capital Monrovia.
He said he was determined to "ensure that every piece of our apparatus is at its optimum so it could deal possibly with a flare-up if that's necessary".
Nabarro is also due to visit Freetown, Sierra Leone; Conakry, Guinea; and Abuja, Nigeria during the trip and then travel to Geneva and New York, headquarters of the World Health Organization and the UN respectively, to report on his findings.
Authorities have been hampered in their fight against Ebola by the deaths of several top health officials and numerous frontline doctors to the virus.
However, two American missionaries who contracted Ebola while treating patients in Liberia and were taken to the US for treatment, have left hospital after making a full recovery.
Kent Brantly, 33, and Nancy Writebol, 60, were given experimental drugs before being airlifted to a hospital in Atlanta where they were treated for the last three weeks.
"The discharge from the hospital of both these patients poses no public health threat," said Bruce Ribner, director of Emory Hospital's Infectious Disease Unit.
Liberia crematorium overflows
Liberia, which has seen the biggest toll in this epidemic with 576 deaths, has witnessed chaotic scenes in recent days following a surge in cases.
The Red Cross said the crematorium in Monrovia was struggling to deal with the dozens of bodies being brought in each day.
Workers were having to return corpses to a hospital in the city because they "did not have the capacity to cremate all the bodies", Fayah Tamba, the head of the charity's Liberian office, told a local radio station.
Her comments came a day after troops used tear gas to disperse protesting crowds after President Ellen Johnson Sirleaf ordered a nightime curfew and quarantine zone in Monrovia's West Point slum and Dolo Town, to the east of the capital.
Guinea, where the outbreak first appeared earlier this year, has sent more than 100 doctors and volunteers to its borders with Sierra Leone and Liberia to monitor people crossing the border for symptoms.
DR Congo fever
As fears grow that the outbreak will spread across Africa and beyond, DR Congo's Health Minister Felix Kabange Numbi said a haemorrhagic fever of unknown origin had killed 13 people in the country's northwest in the past two weeks.
"All 13 people who have died suffered from a fever, diarrhoea, vomiting and, in a terminal stage, of vomiting a black matter," he said.
The first victim was a pregnant woman and the 12 others -- including five medics -- died after coming into contact with her. About 80 people who had contact with the deceased are also under observation.
Samples taken from the victims are to be tested to find the exact strain of the pathogen and results are expected in a week.
Ban's special representative for Liberia, Karin Landgren, said the region was in urgent need of international medical personnel as well as basic supplies including chlorine, gloves and body bags.
"Health-care systems in the most affected countries were weak before the outbreak. Now they are overwhelmed," she said.
Fears that the virus could spread to other continents have seen flights to the region cancelled, and authorities around the world have adopted measures to screen travellers arriving from affected nations.
South Africa on Thursday issued a ban on non-citizens travelling from Guinea, Liberia and Sierra Leone, which it labelled "high-risk countries".