By Gavin Pattison

GULU, Uganda (Reuters) - Health experts fighting an outbreak of the deadly Ebola virus in northern Uganda said Monday they would start searching for the origin of the epidemic as soon as it had been brought under control.

Officials in the town of Gulu said one more person had died of Ebola in the last 24 hours, bringing the death toll to 55. A further 160 suspected cases were being treated in the town's two main hospitals.

A team of experts from the Atlanta-based Centers for Disease Control and Prevention said they had begun testing patients and would soon be able to quickly isolate those who were carrying the disease.

``We've set up the lab in Lacor hospital and we're able to run several tests routinely now,'' Pierre Rollin, leader of the U.S. team, told Reuters.

He said that once the lab was fully operational it would be able to handle dozens of blood samples simultaneously. Friends and relatives of Ebola victims would then be quickly tracked down and tested themselves. There is no known cure for the hemorrhagic fever, which is spread by human contact and brings massive internal bleeding.

Government health officials said at the weekend they hoped the numbers of reported cases would stabilize in the coming days.

Scientists To Search For Clues

Before the present outbreak, Ebola had claimed 793 lives in nearly 1,100 documented cases since it was first discovered in what was then Zaire in 1976.

Rollin said that once the spread of the epidemic had been checked, the team would start work immediately to search for the source, or reservoir.

``We still have no known reservoir for the virus. So we really want to find that,'' he told Reuters.

He said if they could find the index case -- the first person or people who contracted the disease in this outbreak -- it would help them to know where to look for the natural habitat of the virus.

``The only way is to try and find the index case, maybe there is one, maybe there are several, we don't know.''

An Ebola epidemic in the west African country of Gabon in 1996 was traced back to one dead chimpanzee found by hunters in the forest. All 19 people who handled the chimpanzee died.

But primates are not the reservoir of Ebola, as they succumb too quickly to the disease. The chimpanzee contracted the disease from another source in the wild, Rollin said. A virus causing the hemorrhagic Lassa fever has been traced to a rodent, which helped health officials stem the spread of the disease.

``We found that the reservoir is a rodent so then you can have some public health measures to educate people, not to go near rodents, to let them in the house or leave food on the table,'' Rollin said.

He said if the index case was discovered, small animals such as rats and bats in the surrounding area would be captured to be tested.