Kenya has become the latest country to ban travellers from parts of Ebola-hit west Africa as Nigeria scrambled to stop the  deadly disease spreading through the continent’s most populous nation.

Kenyan Health Minister James Macharia said Saturday that the country is closing its borders to travellers from Guinea, Liberia and Sierra Leone -- the nations most affected by the worst-ever Ebola outbreak.

National carrier Kenya Airways also said it would suspend its flights to Freetown and Monrovia when the ban takes effect on Wednesday.

The move comes amid an international appeal to help contain the deadly virus, which has already killed 1,145 people across west Africa this year.

In Spain, where a missionary priest died recently of Ebola after being infected in Liberia, another person was being tested for the disease and was placed in hospital isolation Saturday

Nigeria’s Health Minister Onyebuchi Chukwu told reporters Saturday that 12 people have so far tested positive for the virus, including the four who died, while 189 others are under surveillance in Lagos and six in the southeastern town of Enugu.

"As you are aware, the patients under treatment have now be moved to the new 40 bed capacity isolation ward provided by the Lagos state government," he said.

He said five of the patients have almost fully recovered but added that an experimental drug, nano silver, intended to be administered on the patients was not approved by the National Health Research Ethics Committee.

He also said the first Nigerian to be diagnosed of the ebola virus, a female doctor, had been discharged.

Nigeria has trained 800 volunteers to help in the fight against Ebola following an appeal by authorities in megacity Lagos for volunteers to make up for a shortage of medical personnel because of a six-week doctors’ strike over pay.

"People have heeded our call for service," said Hakeem Bello, a spokesman for Lagos State Governor Babatunde Fashola.

"We have trained some 800 volunteers in the area of contact tracing, sensitisation and treatment of the Ebola disease," he added.

Experts say Ebola is raging out of control in the region, with the World Health Organization declaring the epidemic an international health emergency and appealing for global aid.

The disease erupted in the forested zone straddling the borders of Guinea, Sierra Leone and Liberia earlier this year and spread to Nigeria last month.

The districts of Kailahun and Kenema in eastern Sierra Leone have become the new epicentres of the outbreak, with charities and health authorities battling to keep it from spreading.

"You cannot mess about here: this virus will kill you. One mistake, one wrong move, and you’re dead -- that’s it," a senior aid worker in Kailahun told AFP.

But officials fear an outbreak in the key regional hub of Nigeria could be far more dangerous, and US health authorities pledged this month to send extra personnel and resources.

Volunteers have so far been deployed to 57 districts of Lagos state but more are needed, particularly to treat those already infected with the disease, Bello said.

Lagos’ state government has stepped up a media campaign to raise awareness of how to prevent the spread of the disease, including radio and television advertisements and public health announcements.

Nigerian doctors have been on a nationwide strike since July 1 to demand a pay rise and better working conditions.

International lock-down

Medical charity Doctors Without Borders, known by its French acronym MSF, on Friday warned Ebola is spreading faster than authorities can handle and could take six months to bring under control.

Draconian travel restrictions have been imposed across west Africa and several airlines have cancelled flights to affected countries in a bid to stop it spreading beyond the region.

Nigeria has also withdrawn its athletes from the Youth Olympics in the Chinese city of Nanjing as a result of the outbreak, state media reported as the games opened on Saturday.

The International Olympic Committee has barred athletes from Ebola-hit countries from competing in pool events and combat sports, affecting three athletes.

Ebola is spread by contact with an infected person’s bodily fluids, such as sweat and blood, and no cure or vaccine is currently available.

The last days of a victim’s life can be grim, characterised by agonising muscular pain, vomiting, diarrhoea and catastrophic haemorrhaging described as "bleeding out", as vital organs break down.

Canada and the United States are both sending consignments of largely untested drugs in the hope of saving hundreds of lives, but officials warn they are likely to have little impact.

Ebola patients flee attack on Liberia isolation clinic

"They broke down the door and looted the place. The patients have all gone," said Rebecca Wesseh, who witnessed the attack on the outskirts of the Liberian capital.

Her report was confirmed by residents and the head of Health Workers Association of Liberia, George Williams.

Williams said the unit housed 29 patients who "had all tested positive for Ebola" and were receiving preliminary treatment before being taken to hospital.

"Of the 29 patients, 17 fled last night (after the assault). Nine died four days ago and three others were yesterday taken by force by their relatives" from the centre, he said.

The attackers, mostly young men armed with clubs, shouted that President Ellen Johnson Sirleaf "is broke" and "there’s no Ebola" in Liberia as they broke into the unit in a Monrovia suburb, Wesseh said.

Residents had opposed the creation of the centre, set up by health authorities in part of the city considered an epicentre of the Ebola outbreak in the Liberian capital.

"We told them not to (build) their camp here. They didn’t listen to us," said a young resident, who declined to give his name.

"We don’t believe in this Ebola outbreak."

The Ebola outbreak, the worst since the virus first appeared in 1976, has claimed 1,145 lives in five months, according to the UN World Health Organisation’s latest figures as of August 13: 413 in Liberia, 380 in Guinea, 348 in Sierra Leone and four in Nigeria.