MONROVIA - Liberia announced the return of the deadly Ebola virus on Tuesday, more than six weeks after the country was declared to have eradicated the disease.
"A new case of Ebola has been reported in Margibi County. The person has died and was confirmed positive before death. He has been buried," said deputy health minister Tolbert Nyensuah.
The official told a radio station the experts had traced and quarantined anyone who may have had contact with the victim, without giving numbers or any details on the patient.
"We are investigating to know the origin of this new case. We ask all Liberians and all other nationals living in Liberia to continue taking the preventive measures," he said.
Liberia's neighbours Guinea and Sierra Leone are both battling the outbreak, which has killed more than 11,000 people, but the coastal Margibi County is much nearer the capital Monrovia than either border.
World Health Organization spokesman Tarik Jasarevic told reporters in Geneva the UN health body had been informed of the case.
The epidemic killed more than 4,800 Liberians before the WHO declared the country Ebola-free on May 9, 42 days after the last confirmed case was buried.
That period is double the number of days the virus requires to incubate, and WHO hailed its eradication as an enormous development in the long crisis.
The United States and several international organisations had urged caution, however, with White House spokesman Josh Earnest warning the world not to forget that the outbreak was still in Sierra Leone and Guinea.
"We must not let down our guard until the entire region reaches and stays at zero Ebola cases," he said on May 9.
The WHO also warned that because the Ebola outbreaks were continuing in neighbouring Guinea and Sierra Leone, the risk remained high that infected people could re-enter the country.
Because of that risk, medical aid agency Doctors Without Borders, at the forefront of battling the outbreak since it emerged in Guinea in December 2013, was also muted in its applause of the WHO's assertion that Liberia had beaten Ebola.
It tempered Liberia's jubilation with reminders that the crisis would not be over for any one nation until the virus has been eradicated everywhere.
Sierra Leone and Guinea had been seeing numbers of new cases drop dramatically but the decline has halted and the countries have been recording around 20 to 27 new cases a week since the beginning of May.
During the months of peak transmission from August to November last year Liberia was the setting for some of the most shocking scenes from the west African outbreak, by far the worst in history.
At the height of the crisis in late September Liberia was suffering more than 300 new cases a week, with uncollected and highly infectious bodies piling up in the streets of Monrovia, a sprawling, chaotic city at the best of times.
The health system - embryonic before the crisis, with some 50 doctors and 1,000 nurses for 4.3 million people - was devastated, losing 192 health workers out of 378 infected.
Schools remained shut after the summer holidays, unemployment soared as the formal and black-market economies collapsed and clinics closed as staff died and non-emergency healthcare ground to a halt.
Liberia, which recorded 389 deaths in one week last October alone, finally saw fatality counts drop below 100 late last year, and into single figures by the start of 2015.