A doctor died from Ebola in the southeastern oil city of Port Harcourt, Nigeria has confirmed.
Health minister Onyebuchi Chukwu said the medic died on August 22 after treating a patient who had contact with the Liberian-American man who brought the virus to Nigeria, and who died in a Lagos hospital on July 25.
"Following the report of this death by the doctor's widow the next day, the case had been thoroughly investigated and laboratory analysis showed that this doctor died from EVD (Ebola Virus Disease)," he told reporters in the capital Abuja.
The latest case brings to six the number of people who have died from the haemorrhagic fever in Nigeria. Fifteen people have now been confirmed to have the disease.
On Wednesday, Chukwu had said that the virus was contained because there were no cases outside Lagos, but warned against complacency in fighting the disease.
News that a doctor died 435 kilometres (270 miles) away will raise fears about the spread of the virus, just as Nigerians began to think that they had stopped Ebola in its tracks.
Port Harcourt, the capital of Rivers state, is the centre of Nigeria's oil industry and home to a number of oil giants, including Anglo-Dutch giant Shell and US firm Chevron.
Chukwu said a patient who had contact with the Liberian-American victim managed to slip through the net and go to Port Harcourt in the last week of July, where he saw the doctor after showing Ebola-like symptoms.
"After four days, following a manhunt for him, he returned to Lagos by which time he was found to be without symptoms," Chukwu told reporters.
"This case would have been of no further interest since he had completed the 21 days of surveillance without any other issue but for the fact that the doctor who treated him died last Friday."
Following the doctor's death, the minister said that several contacts had now been "traced, registered and placed under surveillance". He did not specify how many.
His widow has shown symptoms of the virus and has been placed in isolation pending results of laboratory tests, he added.