* Doctor treated contact of Nigeria's first Ebola case
* Port Harcourt at centre of Africa's biggest oil industry
* Contacts traced in continent's most populous state (Adds shippers, oil traders, Shell, World Health Organisation)
By Tim Cocks and Julia Payne
LAGOS/LONDON, Aug 28 (Reuters) - A doctor in Nigeria's oil hub of Port Harcourt has died from Ebola after treating a contact of a Liberian-American man who was the first recorded case of the virus in Africa's most populous country, the Health Ministry said on Thursday.
Health Minister Onyebuchi Chukwu said in a statement that the doctor fell ill after treating a patient who was a contact of Patrick Sawyer, who died from Ebola in Lagos after flying in from Liberia last month.
The death in Port Harcourt brings the number of Ebola fatalities in Nigeria to 6, all of whom were direct or indirect contacts of Sawyer.
The man who infected the doctor in Port Harcourt had "evaded our surveillance team in the last week of July" in Lagos, Chukwu said. He has since recovered and has been discharged after testing negative for the virus.
However, a World Health Organisation official told journalists in Geneva on Thursday that it was not confirmed that the doctor died of Ebola and that a WHO team flew out two days ago to Port Harcourt to assess the case.
The total number of recorded Ebola cases in Nigeria had risen by two to 15, Chukwu said, the other one being the wife of the deceased doctor. She was showing Ebola symptoms and test results were being awaited, he said.
The U.N. health agency said on Thursday that the Ebola epidemic in West Africa could infect more than 20,000 people and that almost half a billion dollars would be needed to overcome the outbreak.
The total death toll stood at 1,552 as of Aug. 26., with 3,069 cases having been reported in the outbreak. The WHO has said the actual number in Guinea, Sierra Leone, Liberia and Nigeria could already be two to four times higher.
The doctor's death in Port Harcourt came two days after Chukwu said authorities had "thus far contained" the Ebola outbreak in Africa's largest economy, with only one case left.
Port Harcourt lies at the heart of Nigeria's two million barrels per day oil industry, Africa's biggest, and is a hub for expatriate workers in major international oil companies, including Royal Dutch Shell, ENI, Total and Exxonmobil.
Nwomeh said 70 people who had been in contact with the doctor were now under surveillance in the city.
OIL OPERATIONS IMPACT
It was not immediately clear what impact the arrival of Ebola would have on oil operations. The majors have historically been comfortable with a fair degree of risk in the oil producing Niger Delta, including attacks on oil installations and kidnappings of expatriates.
A spokesman for leading operator Royal Dutch Shell in London said the firm was "monitoring the Ebola outbreak very closely, and liaising with health authorities on the steps being taken to contain the disease."
The only actions he wished to make public were a "health education campaign for staff and contractors."
Shell also said it had advised against non-essential travel to Nigeria.
Two oil traders in Europe said there were some government restrictions on shippers bound for some of the countries in the region and insurance risk premiums had gone up slightly, but otherwise business was continuing as normal.
A shipping source and an oil trader in London both said there were no restrictions on vessels carrying oil from Nigeria, but that some tankers have instructions relating to crews. A Nigeria-based oil trader from a major international trading house also said nothing had changed.
"While major disruption to oil production appears unlikely, any further spread of Ebola ... is likely to cause serious operational challenges," including travel restrictions, said Roddy Barclay of Control Risks.
"Crew changes and vessel port calls will also face disruption due to potential restrictions on onward travel." (Writing by Tim Cocks; Editing by Raissa Kasolowsky)