Liberia Ebola
Members of Liberia's Ebola Task Force enforce a quarantine on the West Point slum in Monrovia, Liberia Getty

Liberia has been declared free from Ebola after 42 days without a new case, the medical charity Médecins Sans Frontières (MSF) has said.

However, it has urged vigilance until the worst-ever recorded outbreak of the virus has been extinguished in neighbouring Guinea and Sierra Leone.

A total of 11,005 people have died from Ebola in Liberia, neighbouring Guinea and Sierra Leone since the outbreak began in December 2013, according to World Health Organisation (WHO) data.

Nearly half of those deaths have been in Liberia, where the outbreak peaked between August and October, with hundreds of cases a week, sparking international alarm. The United States sent in hundreds of troops to help build treatment clinics in a country founded by freed US slaves.

President Ellen Johnson Sirleaf's government launched a national awareness campaign to block the fatal disease, which is spread by physical contact with sick people.

MSF said that Liberia's completion of the WHO's benchmark for the end of an Ebola epidemic - 42 days without a new case, marking twice the maximum incubation period of the virus - should not lead to complacency.

Medical staff working with Medecins sans Frontieres prepare to take food to patients kept in an isolation area in Kailahun. Sierra Leone now has the highest number of Ebola cases, at 454, surpassing neighbouring Guinea where the outbreak originated in February Reuters

"We can't take our foot off the gas until all three countries record 42 days with no cases," said Mariateresa Cacciapuoti, MSF's head of mission in Liberia. She urged the authorities in Monrovia to step up cross-border surveillance to prevent it returning.

MSF - which was highly critical of the slow response by the United Nations and western governments - opened the world's largest Ebola management centre in Monrovia, with a capacity of 400 beds.

According to the WHO, a total of 868 health workers have caught the virus in Guinea, Liberia, and Sierra Leone since the start of the outbreak, of whom 507 died.

International Medical Corps (IMC), a charity that ran two Ebola clinics in Liberia, appealed for international support in rebuilding the healthcare system there in the wake of the virus.

"Now is the time to build on the momentum we have generated to strengthen the Liberian health system ... and change attitudes to keep the people of Liberia safe long into the future," said Anouk Boschma, IMC's acting country director in Liberia.