A statement by UN Women said Edmund Bangura-Sesay, a local driver for their office in Sierra Leone, died on Saturday.
The statement said Bangura-Sesay was quarantined last Tuesday after his wife showed symptoms. It said his wife remained under treatment, and that the UN was working to make sure that everyone who came into contact with Bangura-Sesay while he had symptoms was assessed and quarantined.
A Sudanese UN medical official who caught Ebola while working in Liberia died last week in a German hospital. The volunteer medic was the second member of the UN mission, known as UNMIL, to contract and succumb to the virus.
In total, more than 4,500 people have died and nearly 10,000 have been infected with the hemorrhagic fever, most of them in West Africa, since the start of the year.
On Monday, the US issued stringent new protocols for health workers treating Ebola victims, directing medical teams to wear protective gear that leaves no skin or hair exposed when caring for patients infected with the virus.
Under the new protocols, Ebola healthcare workers must undergo special training and demonstrate competency in using protective equipment designed to prevent their exposure. Use of the gear, now including coveralls, and single-use, disposable hoods, must be overseen by a supervisor to ensure proper procedures are followed.
Health officials have warned that the Ebola outbreak could escalate and become a global threat if efforts to contain the virus are not stepped up.
Positive news emerged, however, earlier on Monday as the World Health Organisation (WHO) declared Nigeria Ebola-free, after a 42 day period with no new cases.
Al Jazeera's Haru Mutasa, reporting from Abuja, said the news had been welcomed by Nigerians.