The Alliance For International Medical Action (ALIMA) runs the country's sole treatment centre in the southern city of Nzerekore, where it has handled six of the 10 confirmed cases recorded since the outbreak was officially declared over in December.
"(Of) six confirmed cases, four have died, one was discharged after recovery and the sixth is still here," said ALIMA emergency co-ordinator Solenne Barbe.
Barbe attributed the high mortality rate to the fact that the recent patients arrived too late to be treated with a good chance of survival.
According to health authorities, that deceased man's wife and her children crossed the border into Liberia before she too succumbed to the virus. One son also died while another remains under treatment in Monrovia.
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In a rare piece of good news since Ebola's reappearance, an 11-year-old girl left the centre on April 8 after a successful recovery, according to ALIMA.
The World Health Organization was first alerted to the reappearance of Ebola symptoms in a Guinean village near the Liberian border on March 16, the same day it declared a similar flare-up over in Sierra Leone.
The WHO has said Ebola no longer constitutes an international emergency, but the announcement of new cases in west Africa has demonstrated the difficulty of managing its aftermath.
The deadliest period in the history of the feared tropical virus wrecked the economies and health systems of the three worst-hit west African nations -- Sierra Leone, Guinea and Liberia -- after it emerged in December 2013.
The virus has since claimed 11,300 lives.