This photograph was taken in a TB ward - not a hundred years ago, but today, in Uzbekistan, in a town which used to be on the shores of the Aral Sea. Thanks to irrigation schemes, the sea is now 70 miles away, and all that remains is disease and despair. Photographs by Gary Calton. Words by Phil Reeves

The outrage and disbelief will never go away, no matter how often Rusten Dyusenov looks through this window. He knows he should be looking at a bay, fanning out into the blue distance from a shoreline only a few yards away. He knows there should be boats and screaming sea birds and the bracing whiff of salt and ozone.

His town, he also knows, should have fishermen, Japanese-style beach pavilions, and sanatoria occupied by holidaymakers, recovering from the trials of faraway cities - Moscow, Minsk and Tashkent.

What we actually see is a few roof tops and, beyond them, mile after mile of desert. We see a dead-flat landscape of rock and sand, relieved only by squat scrub bushes, rusting drums and the occasional cow, picking its way through the parched sea-bed in search of edible life. There is not a glimmer of water in sight, not a gull's screech nor the distant thud of a trawler's engine.

"This is very hard to bear," he says, shaking his head. "God forbid that it should happen to anyone. Not to you, not to me, not to anyone."

Dyusenov, deputy mayor of Muynak, has probably made this speech many times in front of this tall, smudged window in the town hall. For years, scientists and government officials have come to this corner of north-western Uzbekistan from across the world to see an environmental catastrophe, the drying-up of the Aral Sea.

As the sea has shrunk to a third of its former size over the last three decades - the fault of Soviet planners who diverted water from its two big feeder rivers into Uzbekistan's cotton fields - Muynak has turned from a fishing town and holiday resort into a desert outpost 70 miles from the water's edge. Coastal settlements across the world have lost fish stocks to pollution or overfishing or both. But who expects to lose the sea? And Muynak's tragedy is entering a new phase, a secondary blight spawned by the loss of the water - the exposure of thousands of square miles of saline seabed, permeated by the pesticides and fertilisers washed into it over the years.

As he gazes at the wasteland and recalls how remarkably blue the water was in his childhood, Dyusenov is surely repeating himself. But then he is talking about a disaster that has not yet run its course. Put simply, the region has a public health disaster. The detailed connections between this disaster and the death of the Aral Sea have yet to become clear, partly because of a lack of research but also because other upheavals must be factored in - like the social disorientation, poverty and loss of healthcare that came with the collapse of the Soviet Union. But the Aral's destruction is undoubtedly hugely influential, as if the sea is taking revenge on the five million people who live around it.

The sea has turned from a rich fishing ground to a prairie of poison dust. With that change have come birth defects, infant mortality, cancers, malnutrition, respiratory diseases, and the anaemia suffered by almost all women of child-bearing age. The water supply is contaminated by salt, as is the land - you can see white ridges amid the soil in the fields. Trees no longer bear fruit. The climate has changed: the winters are even colder, summers even hotter. Toxic, lung-caking dust storms rip across the plateau. Stripped of a main source of income, the people are poorer still. Malnutrition has risen sharply; fish is no longer part of their daily diet.

And then there is the killer, the disease that some Western experts see as the biggest threat to the world's health in the next millennium: tuberculosis.

TB has simmered in the region for decades, but in the last few years it has rocketed. Muynak has been engulfed. New cases last year ran at an estimated 200 per 100,000 people, about the same as the notorious Russian prisons, which are notorious for their squalid conditions and dismal diet. Western agencies believe the Aral Sea area is witnessing the worst outbreak of the disease in the whole of the former Soviet Union.

The statistics - though always unreliable in this part of the world - confirm the epidemic. Muynak is in Karakalpakstan, a republic within Uzbekistan with a tenth of the population of London. Local officials say that last year TB - broadly speaking, a curable disease - claimed 512 lives locally, and 2,000 throughout Uzbekistan. According to one Western expert, Muynak's 28,000 residents are living in one of the "most chronically sick places on earth". So sick that they seem not to have grasped what has happened.

The 300-vessel fleet once employed 1,000 fishermen. It is now a collection of rusting hulls half-buried amid the dunes on the edge of town. Yet the 60-year-old canning factory still clatters, all steam and stench, although its 700 workers handle fish brought by lorry from the lakes around Tashkent, 1,000 miles away. Pathetically, the plant director, Daulbai Kdirniazov, says he is hoping for foreign investment, a dream as improbable as the return of the water.

Couples still go up to the Second World War memorial on their wedding day, where they used to look down over the water's edge, drinking champagne, clutching bouquets, and posing for photographs in front of what was once a glorious seascape but now looks like outback Arizona.

A brightly painted fishing boat, decorated with bunting, stands outside the town hall, advertising a moribund industry. The streets display cheery Soviet-style placards showing local fishermen working with their nets against an azure sea. But you can only play make-believe for so long. The myth fails at the gates of the 50-bed tuberculosis hospital, a cluster of one-storey houses on the edge on Muynak. "These days there are more and more young people," says Amanbai Mambetkdirov, the region's chief doctor, before he shows us into an airless ward where three women lie on iron beds.

Like several of Uzbekistan's senior officials, he seems torn between conceding that there is a serious problem and robustly defending the system in which he functions. They praise the solid but limited Soviet healthcare methods and point out that TB is a global blight which is present in the US and which - still more crucially - is worse in Russia, if you take the national figures. Uzbekistan's overall incidence rate is an estimated 54.8 per 100,000, while Russia's is 82.3.

But these figures should be treated with care. Prison populations, among whom TB rates are usually significantly higher, are not included in these numbers - largely for political and bureaucratic reasons.

In a world largely untouched by perestroika, let alone democracy, officialdom is wary. But there are signs of change, at least over the issue of TB. Muynak is the centre of one of two pilot programmes in Karakalpakstan, spearheaded by Medecine Sans Frontieres (MSF), which aims to provide more effective and economical treatment. Among other things, it encourages clinics to forgo the Soviet practice of keeping TB patients in bed for a year, moving the emphasis to out-patient care. The method, pioneered by the World Health Organisation (WHO), is called DOTS - Directly Observed Treatment, Short course.

This is a start, but the hurdles are formidable. Medicine supplies are unreliable, even though Uzbekistan says it now manufactures four of the five standard drugs. Money is short. Hard medical data is sparse. Clean water and good sanitation are minimal.

Most alarmingly of all, drug-resistant strains of tuberculosis are on the increase - encouraged by sufferers who stop taking their drugs when they feel better, but before they are cured. TB thus transmutes into a drug-immune form, which can be passed on by a cough. Exactly how many people here have drug-resistant TB is uncertain; Uzbek officials say 17 per cent, but Western sources reckon this statistic surfaced in 1989 and the figure may now be one in three.

If this is true, then the worst may be to come. Hospitals have yet to separate the non-resistant patients from the rest, although they are starting to do so. Non-resistant TB costs $50 to cure; drug-resistant variants require 20 times as much - well beyond the means of this Central Asian nation.

In their trauma, the people of Muynak have not lost hope. "There was such beauty here, such natural beauty," says Dr Mambetkdirov, Muynak's chief doctor. "People came from all over the world." He tells the local legend of how the Aral Sea has twice gone away and twice returned, as if he half-believes that the waters will come back.

But that's for fairy tales. That was before the giant Soviet irrigation canals came along, before Uzbekistan became dependent on the hard currency earnings from its cotton crops. There's a new task, now, and - according to MSF - a pressing one.

Countless scientific expeditions and assessments have been conducted around the Aral Sea. Ian Small, head of mission for MSF's Aral Sea Programme, remarks that the population is "assessment-fatigued". But far less work has been done on the wider impact of the environmental catastrophe.

"There is a common saying in the region: if every specialist coming to the region brought a bucket of water, the Sea would be filled again," Small comments. "At this point there is a wealth of information on the causal nature of the disaster, but despairingly little on its effects on human health."

They, we, everyone - had better hurry up. If the Aral Sea dries up completely, 15 billion tons of salt and chemicals will be exposed to the air. They will then be carried by the winds which crisscross the area and will be dumped over Central Asia. No one knows what harm that would do, but the town of Muynak provides a horrible clue