The new killer threatening rich and poor alike

The White Swan Hotel in Guangzhou, sometimes called Baby Hotel or the Stork Inn, is one of the places in China where western couples, most of them American, spend their first days with their newly adopted Chinese children. The hotel has become so specialised, according to a recent report in the New York Times, that it offers each adopted child a blonde Barbie doll which "holds in its grasp a baby that is unmistakably Chinese." Could there be a clearer, or, in its way, a more pleasing example of the manner in which the barriers which divided the world until only a few years ago have come down?

Unfortunately, barriers stop bad as well as good things, and babies in need of parents are not all that comes out of China. The south of that country has been long known as a reservoir of influenza-like diseases, which some trace to the integrated duck and pig farming of the region. Six months ago a new one emerged and spread, first locally, then into northern China, south-east Asia, Hong Kong, and thence to many other parts of the world. The microbe utilised the human links represented by tourists, businessmen, students and family members crisscrossing between the far east and migrant communities in Canada, the United States and Europe.

Just as the conditions which favoured the transmission of the disease could be measured in retrospect by the high occupancy rate of hotels and the healthy level of airline bookings, so its spread can be measured by statistics pointing in the opposite direction. Empty hotels and cancelled flights mark the path which severe acute respiratory syndrome, or Sars, has followed. There were political conditions favourable to the spread as well, in the shape of China's habit of concealing bad news and fixing figures, and, in this case, its decision to ignore its obligation, admittedly moral rather than legal, to inform the World Health Organisation that it had a serious problem.

The travel and tourist industry has taken the first blow, but the effects will go much deeper. A global economy already damaged by the impact of terrorism and by the Afghan, Iraqi and Palestinian conflicts has been further undermined. One estimate suggests that Canada could lose as much as $30m (£12.9m) a day because of the World Health Organisation's recommendation this week that travellers avoid Toronto. Hong Kong has brought in a costly package of tax breaks, loan guarantees and temporary jobs to ease its tourist industry through hard times.

China is already suffering and will certainly suffer even more. The fall in income from tourism, trade and airline travel, and the likely reduction in foreign investment, will particularly hit Guangdong province, one of the country's most important growth regions. And all this at a time when the single best hope for the world economy was represented by the prospects for the greater China region.

The World Trade Organisation, which seems almost umbilically linked to the World Health Organisation at such a moment, has revised its growth estimates downward because of the disease. Sars, while not yet an epidemic, is thus increasing the sum of human unhappiness in the classic manner of such diseases, by its effect on the actual victims and their families and through its broader economic impact.

The new disease constitutes the first test of the early warning system which the WHO set up after its experiences with ebola. The Global Outbreak Alert and Response Network, which links 100 countries, with laboratories in 10 of them, was supposed to prevent the world being taken by surprise by a new pathogen. But members of the WHO are only obliged to report three diseases - yellow fever, plague and cholera - and even then there is no sanction if they fail to do so.

The new alert system is voluntary, its definitions of what should be reported are vague, and China's concealment has meant the test has not been an entirely fair one. In particular, research work on the virus or group of viruses could have begun earlier had China been more honest, and diagnosis would have been more advanced. Instead, it was left to an Italian WHO doctor, working in a Hanoi hospital, to identify the new disease and issue the first serious warning. Carlo Urbani paid for his dedication with his life, and his work may be posthumously recognised, if public health researchers have their way, by having the Sars virus, once successfully isolated, named after him.

If the disease had been identified earlier, could it have been confined to China or to east Asia? Given its mutability, which may bring with it, apparently, greater degrees and types of contagiousness, and the huge volume of travel in and from the region in which it arose, this may be doubted. The isolation of the sick, barrier nursing and specialised medical care are difficult even in rich countries once numbers go beyond a certain point, even more so in poorer ones.

The question is one to which the answer may never be known, just as we do not know whether the precautions which health officials in all countries are now taking will be useful in preventing the further spread of Sars. They are dictated by the need to be seen to be doing something, and they represent best practice on the basis of previous experience. They also show officials faced with the familiar dilemma of weighing one kind of risk against another. Over- reacting to the physical risk of the disease carries the danger of inflicting economic damage for no necessary reason.

Sars, to date, is a bad but not a truly terrible disease. The mortality rate in Hong Kong, for instance, has been similar to that for pneumonia, which kills 2,000 to 3,000 a year there. Contagious although it is supposed to be, it has not so far infected huge numbers of people. Even if it were to become more of a killer than it is, there is some reassurance to be found in the fact that diseases which kill many of their victims quickly are by definition not efficient diseases, and therefore have a tendency to evolve ultimately into less malign versions. We are not, or not yet, in another year of the plague.

But what Sars has done is to further shred the belief in better-off parts of the world that protection from serious infectious diseases is a sort of human right. That belief, although battered, has survived ebola, because it did stay confined, and even Aids, because relatively long-term survival was often possible with the right drugs.

But a reluctant consciousness may be dawning that, as the historian William McNeil wrote in his book Plagues and Peoples many years ago, there can be no guarantee against the possibility that "some hitherto obscure organism may escape its accustomed and original niche and expose the dense human populations that have become so conspicuous a feature of the earth to some fresh and perchance devastating mortality."