Not a season to be merry: Winter grips Bosnia with claws that draw blood, bringing with it ice, hunger, and diseases old and new. Visit hospitals there and you see that things are at least as bad as you imagine. Celia Hall reports

In Bosnia-Herzegovina, because of the war, people are dying from tuberculosis; hepatitis A is breaking out sporadically across the region; the first signs of vitamin deficiency are being seen, in bleeding gums and night blindness; and now the health authorities fear a more terrible scourge - that winter will bring typhus.

There are very real fears for the winter. Dr Hannu Vuori, who heads the World Health Organisation operation based in Zagreb, says that large numbers of people will die of cold in the coming months.

Three weeks ago they launched their own appeal to the world to help them to create stockpiles of emergency supplies. Their Christmas present list reads like this: 5,000 aluminium foil space-blankets; 100,000 ordinary blankets; 100,000 pairs thermal underwear (medium); 100,000 pairs thermal underwear (large); 150,000 pairs thermal socks; 150,000 pairs thermal gloves; 5,000,000 iron tablets; 40,000,000 vitamin C tablets.

The WHO reckons that the health services are on the verge of collapse, which means that those who live in or fight for Bosnia must rely increasingly on medical aid getting through the front lines.

Just a few days in Bosnia makes one certain that these are not cries of wolf. In Bihac, in the north, where a peculiar war-within-a-war is being fought, the situation makes the supplies of aid uncertain. In this doubly contested province the separatist Muslim forces of the politician and businessman Fikret Abdic are fighting the forces of the Muslim Bosnian president, Alija Izetbegovic.

We knew, because we had been told, that hospitals in southern Bihac were short of dressings and other supplies and we knew, because we had been there, how cold the buildings were. Mr Abdic admitted that for two weeks his forces had stopped UN supplies from the north crossing into the south of Bihac. Our little group, including a journalist from Italy's La Repubblica and another from Liberation of France, met Mr Abdic after we had stood in the snow surrounded by his soldiers outside the gates of his massive Agrokomerc organisation and offered our business cards through the railings.

He explained that supplies had been stopped because the units of the UN protection force who patrol this area had 'acted illegally'. This had lately been resolved, he said.

There are now more than three million refugees or displaced people in former Yugoslavia; 230,000 people are missing or have been killed; 60,000 have been seriously wounded. In Bosnia 29 per cent of the population are estimated to have been displaced or made refugees.

The hepatitis, the TB and the vitamin deficiencies are markers of the effects of war. In Yugoslavia before the conflict TB was more common than the European average. WHO field officers say that the current deaths are likely to be TB patients who have been dislocated and so cannot get their drugs.

The typhus fear is well based. After the Second World War there was a typhus epidemic in the Balkans. People died in their tens of thousands; no one knows exactly how many. The conditions now in Bosnia are good for typhus, and getting better.

Typhus is caused by micro-organisms called rickettsiae, which are spread by body lice. The rickettsiae get into the bloodstream when people with lice start to scratch. Lice spread when people live in overcrowded and insanitary conditions, when there is insufficient water to keep clean, and so little fuel that people congregate to keep warm.

Once a person is infected, the disease appears rapidly, in three to five days, and spreads quickly. Usually there is a severe headache and pain in the back and limbs. There is a bad cough and constipation, followed by a high fever, a body rash not unlike measles, a weakening heartbeat, and often delirium. Without treatment with antibiotics, the old, the young and the weak will die because their hearts will fail, or their kidneys, or they will develop pneumonia or septicaemia.

Dr Julius Weinberg, World Health Organisation health monitor, said in Zagreb last week that conditions were 'now ripe' for an epidemic. 'Since the last war there have been regularly four or five cases a year in the region, so we know it is still there. We know there is a pool of infection and our great concern is that people will gather together because of the winter, just to keep warm. If typhus happens it could be catastrophic.'

They are putting their faith in two things, he said: the high standards of personal hygiene among Bosnian people and the fact that the medical structures in former Yugoslavia were well established. Although the country has fragmented, local systems for providing health care do exist. 'We are working with the authorities, who have been very active, to distribute thousands of puffer packs of insecticide,' Dr Weinberg said. In addition, supplies of mass delousing kits called Millbank Dusters are being distributed. These are hardly hi-tech: they are used to puff insecticide up men's trouser legs.

It is beautiful in Bihac under thick snow, and in the mountains, but it is place of terrible contrasts. Children are sledging with their dogs. Yet in the hospital in Bihac town lay a boy, perhaps four years old, who had the previous day been shot in the head by a sniper. The nurses did not know the child's name. He had been brought in by ambulance from the other side of the lines.

In Sarajevo it is not beautiful. It is a place of great desolation and anguish, and of such destruction that now you cannot find 10 square metres on the Bosnian side that has not in some way been damaged.

Aside from the black market, the mass of the people, about nearly 300,000 of them, exist on aid. I flew in with 40 tons of it - pasta, tinned vegetables, women's boots - in an Ilyusian plane of the International Committee of the Red Cross.

But every time you ask, everyone you ask, you hear the same thing. It is fuel they lack. Diesel to power hydro-electric plants, diesel for hospitals with central heating systems. But diesel is political as well as humanitarian; armies need it, after all.

The State Hospital in Sarajevo was the national military hospital before the war. Dr Bakir Nakas is a former Yugoslavian National Army doctor and a consultant in infectious diseases at the hospital. Now he is its civilian director. He is also the chairman of the Sarajevo committee that co-ordinates the distribution of medicines. Here, as in the other Muslim hospitals I visited, were portraits of Tito - a symbol, it was clear, of unity. In 20 months they have treated 7,000 wounded, most of them emergencies and most of them with multiple injuries. They are running at about half capacity in terms of beds and staff but Serbian doctors and nurses still work there together.

For 66 days in July and August they had no water. Last week there was water and some electricity. But they have no fuel for the central heating. There is barely any wood now either.

Dr Nakas is pleased with their improvisations. Wood-burning stoves have been installed in the two- and four-bed wards and these have been fitted with gas rings. They have dug up the gas pipes and made their own connections. So the supply comes down flexible pipes, through the windows.

The corridors and stairways are without light. Dr Nakas, who is remarkable in many ways but notably for his resolute sense of humour, leads the way wearing a miner's lamp on his head. This, he explains, he normally wears in the operating theatre for when the electricity is cut.

He has a box of bullets and twisted metal on his desk in his cold office, gratis the Serbian forces in the hills. These he has collected from the balcony. His windows are wide and you can see the hills. The round that did enter his room missed him but broke the glass of the hospital's symbol above his head.

'They know me. They can see me,' he says, unconcerned for himself. He is concerned for his patients. The city has been besieged now for 20 months.

'Six months ago patients were getting 450g of food a day. Now it is 250g. It is not enough. We are having great problems with the ability of patients to recover after surgery.'

Last winter it was sometimes so cold in the operating theatre that saline fluid froze in the bags. 'This winter if we have no electricity and no gas, then I expect that 100,000 people will die,' he said.

(Photograph omitted)