Olaf Ullmann died in hospital in Berlin on Friday, five days after returning from a trip to the jungle in the Ivory Coast.

Authorities at Hamburg's Robert Nocht tropical medicine laboratory, which had been working on the case, said the diagnosis of yellow fever was held up because the man had been vaccinated against the disease.

However, some people are still vulnerable even after immunisation.

Mr Ullman who had been making a film, was being treated in a hermetically-sealed isolation unit at a Berlin hospital.

A biologist who accompanied the cameraman is also in hospital but so far has shown no symptoms of disease.

The initial theory that Mr Ullman had contracted Ebola prompted widespread alarm in the German media.

Ebola deadly to more than 50%

An outbreak of Ebola virus in Africa four years ago killed hundreds of people.

The only known case of Ebola in Europe was in 1976, when a scientist at Porton Down laboratory in Britain accidentally pricked himself with an infected needle. He survived.

Mr Ullman was being treated by medical staff dressed in airtight suits and wearing breathing apparatus.

More than 100 people who have come into contact with the two men are undergoing thorough check-ups, but health officials have said it is unlikely that any virus could be passed on, as he came to hospital shortly after getting symptoms.

It is not the first time Germany has been put on alert by a tropical disease. The Marburg virus was first identified in 1967 in the North German town of the same name after a laboratory worker who was taking blood from African monkeys became infected.

Seven people died in the outbreak.

Cure hopes

The Ebola virus multiplies rapidly in the human body and quickly overwhelms it, and in advanced cases the patient develops high fever and severe bleeding.

As yet it is untreatable, hence its terrifying reputation.

However, earlier this week a Nigerian scientist announced he had found a plant that could prevent the virus from replicating itself.

The treatment, using a compound from Garcinia kola, a plant commonly eaten in West Africa, was hailed at an American conference as a breakthrough in the fight against disease.