"It is like watching someone dissolve before your eyes," said Barbera Kerstiens, a Belgian doctor who worked on an outbreak in the Congo two years ago.

Scary? Oh yes. For people living within striking distance of Gulu, where World Health Organisation officials on the ground says there have been 43 deaths so far, Ebola is the Black Death turned sci-fi. Health workers and international scientists go from hut to hut in protective clothing, Latex gloves and face masks, asking who has died and taking the names of family members who could be next.

In Gulu, Ebola haemorrhagic fever has struck from nowhere, as it habitually does. It was first identified in 1976 in the Democratic Republic of the Congo (formerly Zaire) and named after the river running through the jungle where the virus appeared to lurk. There have been outbreaks in Sudan, Cote d'Ivoire and Gabon. The most serious outbreaks were the two in the Democratic Republic of the Congo, in 1976 and then 1995, where around 300 people were infected and 80 per cent of them died.

What will happen in Uganda is anyone's guess, because there is an important difference in the location of the latest epidemic. It is not in a remote rural community, but a densely populated area. Not only is it far harder to track down and isolate anyone who has come into contact with those who have fallen victim, but Gulu is at the heart of a 12-year rebellion by the Lord's Resistance Army. Nearly half a million displaced people live in camps, in crowded and sometimes squalid conditions. Just the sort of conditions that the virus needs to spread.

Ebola is frighteningly infectious, easily passed through contact with the blood or bodily fluids of victims. Some people have caught it through the traditional local practice of washing the bodies of those who have died. Already it has destroyed families.

Joyce Akello, 30, sits among a small group of women on the patchy grass outside Gulu government hospital's Ebola "isolation" ward - a low building with wooden shutters covering glassless windows.

"I'm here because I have a patient about to die," she says as she pulls her makeshift facemask away from her mouth. "My brother went to a funeral of a sick person and when he came back the sickness followed him. He died in hospital and now his wife is admitted and my younger brother is here. He has blood from his mouth and he is confused."

The Ugandan authorities have confirmed 39 deaths and 55 lying sick with the disease. Some have recovered and are being kept in quarantine, while others are being kept alive by under-resourced and overstretched medical staff at Gulu's two hospitals. Medical officials believe the true number of sick could be far higher and this week began sending out surveillance teams to all the affected sub-counties in an effort to trace others who might be incubating the disease which sometimes does not show symptoms for 21 days.

The nightmare truth - that it was Ebola - was only confirmed last weekend, after samples were sent to South Africa for analysis. Even testing for the virus is dangerous and needs carefully controlled laboratory conditions. The Ugandan authorities, with help from the WHO and the American Centres for Disease Control have now belatedly swung into action. There is an attempt to use threats of force to isolate and quarantine areas where the disease has shown itself and people try to run from the danger, but three cases have already turned up 50 miles from Gulu.

The hospitals are at last getting supplies of plastic gloves, caps and aprons, although there are still not enough to go round and local seamstresses are running up extra masks. But their task is impossible. Each night thousands of people seek refuge from the threat of rebel attack at the Lacor mission hospital. Their fear of the rebel soldiers outweighs their dread of the disease. In Gulu, death beckons from every corner.

Those who survive Ebola will be lucky. Victims need intensive care in a first-rate hospital. They need fluid and they need support for their organs while their body tries to fight the virus. There are no drugs to help.

The Ugandan authorities are placing most faith in prevention. At Gulu's Radio Freedom a receptionist wearing plastic gloves - to stop contamination from visitors - sits in front of a tiny run-down room which is broadcasting a safety message from the district health inspector. Listeners are told to buy bottles of bleach and scour thei r home. They are warned to suspend cultural practices associated with burying their dead - such as washing the corpse - in case they contract the disease, and to be careful of body fluids like spit and urine.

Health workers being given basic training at the local council offices, listen attentively as they are shown how to clean their vehicles after they enter infected areas, and watch as they are shown how to record and register those who came in contact with the dead. The residents of Gulu are panicked but not scared, and partly reassured by the stream of international health workers and health ministry officials who have been arriving in the town.

There is the acceptance of their fate that belongs to people used to adversity, living in one of the poorest and most marginalised areas of Uganda torn by conflict and brutality. Ambushes are frequent on the roads and the infrastructure is basic. Thousands of children have been abducted by the Lord's Resistance Army and forced to become soldiers and sex slaves.

"I would say that Gulu is a really unlucky place. I cannot tell why. Maybe it is God making it so," says Komakech, a volunteer health worker, as he waits outside a room where he had been shown how to wrap up a contaminated corpse.

So life goes on as normal, although people have stopped greeting each other. In the local council headquarters, the driver of a local security chief lunges forward to shake hands, and then lunges back in exaggerated mock fear, his hands tight behind his back.

What has Gulu done to deserve this visitation? Where did the virus come from so suddenly and unexpectedly? WHO officials now think the first case may have been a baby, reportedly the child of refugees fleeing the Lord's Resistance Army, who became ill in August. The virus could have come out of Sudan, the theory runs, which harbours and backs the rebel militia. Or it could have arrived courtesy of another war - the fighting in the Democratic Republic of the Congo in which seven nations, including Uganda, have troops.

But whether war or adventure or ambition was to blame, it is likely that the outbreak of Ebola in Gulu, like all the others before it, was the direct result of man's incursions into uncharted territory. The virus appears and disappears. Somewhere there is a reservoir, because each time it appears - in the DRC or in Sudan or in Cote d'Ivoire - it is remarkably similar. And that reservoir is probably an animal species which acts as host and has lived and evolved happily and disease-free with the virus for many hundreds of thousands of years.

"Ebola is almost certainly resident in some vertebrate species in some forest environment, living a very healthy life," says Ernest Gould, assistant director of the centre for ecology and hydrology in Oxford which is part of the national environment research centre. "Probably it has been doing this for hundreds of thousands of years. Humans are encroaching on the environment of the virus. More and more frequently, humans go into the environment - we're assuming it is forest but it might be caves - where the virus is natural and harmless to the species it inhabits and become exposed. It is happening more frequently now because humans are more mobile and we are cutting down the forests." Mining could also be a factor.

It happened with HIV. The virus that is causing such grief to humankind lived passively among monkeys. It, and the monkeys, had evolved so that they could co-exist, doing each other no damage. But then it jumped species.

Monkeys are probably not the host for Ebola, because they get ill. But they are thought to have been the transmission route in past outbreaks, when people have eaten infected animals or even handled their corpses. The host may be a rodent, says Dr Gould, or some other vertebrate. Scientists are testing hundreds of species in an attempt to find the reservoir for a virus that does so much damage to man.

Ebola virus is not like HIV because it is not mutating and because once people are infected they get ill - they do not carry it and pass it on unwittingly for years and years. "It keeps coming back from the source," says Dr Gould. "It doesn't perpetuate itself."

It is from a family called the filoviruses. Our knowledge of them dates back only to 1967 when 31 laboratory workers in Germany went down with what became known as Marburg disease - named after the town where they were working. They had been infected by African green monkeys. Seven people died.

The filoviruses have taken the same route to the west on a couple of occasions. In 1976, a lab worker in the UK pricked his finger on an infected needle and became ill from Ebola but survived. In 1989, monkeys imported to Texas from the Philippines developed a strain called Ebola-Reston, which infected their handlers but did not make them ill. The incident was the inspiration for Outbreak, a Hollywood scare story starring Dustin Hoffman who saved the US from the spread of the deadly virus by inventing a vaccine.

Could it happen? Could Ebola spread beyond its African forest crucible, spreading misery and a particularly nasty way of death worldwide, like HIV? Very unlikely, say the experts, even though infectious diseases are on the move as air travel becomes more and more common. Diseases like Ebola only flourish in insanitary conditions. Epidemics are short and nasty and then die out. Or they have until now. Almost certainly, the Gulu epidemic will be contained, but conditions are ripe for a good deal of spread and a lot more deaths first.

(From Sohu)