It is caused by a silent virus that invades the nose, throat and bronchial tubes. The virus is easily passed from person to person through the air, by the droplets expelled when the infected cough or sneeze.
It then takes between one and four days to develop symptoms, and what makes it especially sinister is that someone who has been colonised by the virus can be infectious even before they show any signs that this quiet killer has taken up residence in their bodies.
The first the victim knows about it is the sudden onset of high fever, headache, a dry cough, a sore throat, sore eyes and a general sense of wretchedness. Many people recover, but for the very young, the elderly and those with serious medical conditions, infection can lead to pneumonia and death. The virus, in fact, is responsible for between 250,000 and 500,000 deaths every year around the world.
The name of this creepy killer disease? Influenza or, as we call it with a casual contempt bred by familiarity, the flu. It's a nasty bug, and we would all be better off without it. But it's part of our world, and even though it killed more people in the 20th century than, for example, the first World War (the so-called Spanish flu of 1918-19 killed an estimated 20 million to 40 million people), we take it pretty much for granted.
Flu is just one of many mass- murdering bugs. The Grim Reaper has an arsenal full of sharp scythes. More than eight million people become sick with tuberculosis each year, and about two million of them die. Malaria causes more than 300 million acute illnesses and at least a million deaths annually. AIDS takes three million lives a year, and even measles kills 950,000. All of these deaths are catastrophic, but we're pretty much used to them.
There is, though, another illness that many regard as the quintessential postmodern disease: panic. Panic attacks, once a cross borne in silence, have become almost an emblem of contemporary culture.
Even Tony Soprano, the ultimate fictional tough guy of our times, is seized by sudden, inexplicable blackout-inducing terror. What's more, his henchmen don't seem to find their leader's seizures all that strange. Panic is in the air we breathe in the early 21st century.
The American Psychological Association defines a panic attack as a sudden surge of overwhelming fear that comes without warning and without any obvious reason. It lists the symptoms as racing heartbeat, difficulty in breathing, a "terror that is almost paralysing", trembling, sweating, shaking and a "fear that you're going to go crazy or are about to die". The symptoms, surely, have been recognisable in Ireland in the way we have reacted to the SARS scare over the past fortnight.
The SARS panic virus invades the brain tissues. It is spread by exposure to too much television and too many tabloid newspapers. The symptoms include an irrational fear of people of Asian origin, the loss of a sense of perspective and a clammy, feverish feeling that everything is out of control.
At first a relatively mild disease, it is made far worse in Irish conditions by the pervasive and by no means unjustified feeling that the authorities are clueless. And the first fully confirmed case - the decision of Clonmel Borough Council not to welcome Special Olympians from Hong Kong after all - creates the risk of an epidemic.
SARS itself is, of course, a genuinely serious business. For the families of the 400 or so worldwide fatalities so far, it is a terrible tragedy. For the medical profession, there is a real duty to do all that can be done to prevent a new virus from taking hold in the human population. Just because SARS is but one of hundreds of potentially fatal bugs, there is no reason not to devote great skill and energy to containing it while containment is still possible. And because time is of the essence in these things, a sense of urgency does need to be generated through the media.
From an Irish point of view, however, the level of fear has been grossly disproportionate to the reality. With just one confirmed case, there is every reason to keep a sense of perspective. All the more so because the SARS scare draws on a deep well of irrational anxiety: the Western fear of the East.
From the mid-19th century onwards, when large numbers of ethnic Chinese and Japanese immigrants began to settle in the US, a stereotype of the Chinese as carriers of physical, racial and social pollution became one of the staples of Western popular culture. Most Westerners of a certain age still have Fu Manchu and Ming the Merciless lurking somewhere in the dusty attics of their minds.
However much the fear of the Yellow Peril may have abated in recent years, it remains a factor in public reaction to SARS. There is no other explanation for the huge fall-off in business at Chinese restaurants, for the reluctance of some people to sit beside a person of Asian origin on a bus or for the over-the-top reaction against the Special Olympics. Does anybody really believe that if SARS had broken out first in Norway, tall blond people would be greeted here with automatic suspicion?
Irish people should be especially sensitive to all of this. The most infamous case of the way racial stereotypes can interact with public-health crises was the outbreak of typhoid fever in New York in 1906 and 1915. The epidemic produced Typhoid Mary, a mythic archetype of the pestilent immigrant infecting a healthy Western society. It is a name that most people have heard, attached to an urban legend that persists to this day.
The typhoid outbreaks were real and deadly, with 3,000 cases and 600 deaths in 1906. But the scare was driven by anti-Irish sentiment. Mary Mallon, an Irish cook who had been in New York for about 20 years, was identified as a symptomless carrier of the disease. She was quarantined on an island for three years, eventually released and then, when the disease broke out again in 1915, imprisoned for another 23 years, until her death, in 1938.
In reality, Mallon was unknowingly responsible for just three typhoid deaths. She was one of dozens of healthy carriers and by no means the most deadly. The others were quarantined for a few weeks, then quietly released. But the typhoid panic required a monstrous figure to embody the fear, and Mary Mallon - Irish, Catholic, female and poor - fitted the bill. The popular press painted her not as an inadvertent carrier of a disease whose symptoms she did not manifest and which she therefore did not believe she had but as a dark angel of deliberate death.
SARS has the same kind of convenient racial profile, though by now we Irish see ourselves not as the outlandish immigrants but as the civilised community threatened by strange foreigners. It is the addition of a toxic racial anxiety to a genuine medical problem that turns a rational concern into a panic.
There is something else in the air, however, something that enhances the fear produced by the virus. Since September 11th, all of us, as consumers of global news, have been taught to worry about biological weapons. The names of diseases - most notably anthrax - have been linked in the new lexicon of political discussion with the threat of terrorism and rogue regimes. We have been primed for panic at the very thought of invisible killers in the air we breathe.
Last weekend, at a conference on bioterrorism in London, Dr Frank Boulton of Britain's National Blood Service made the parallel explicit when he pointed out that the SARS panic will have gladdened the hearts of so many terrorist organisations. If SARS were a biological weapon, it would be the perfect demonstration of the destructive effects of bio-panic.
Although the direct effects of the virus are limited, its indirect economic effects have been massive. Large parts of the already fragile airline industry have been hammered. The economies of the Far East have been crippled by the effects on tourism, travel and investment. Indeed, if the likes of Osama bin Laden hadn't thought seriously about the potential of bioterrorism before, it's a safe bet that, having seenthe effects of SARS, they're doing so now.
The most effective spreader of panic in Ireland, however, was almost certainly the sense that the authorities were all at sea. After September 11th, few of us lost more than a few minutes' sleep over the real but relatively remote possibility of a terrorist attack on Sellafield. Until, that is, we heard the hapless junior minister Joe Jacob on Marian Finucane's radio show, giving us his clownish impersonation of reassurance. If this was the voice of calm, rational authority, then panic began to seem the only rational option.
Something similar has happened with SARS. Initially, most Irish people seemed quite calm and realistic, vaguely confident that somebody, somewhere was in charge. Then the public-health doctors went on strike, Micheál Martin lost the plot, nobody seemed able to answer basic questions and travellers noticed that, right up to the early days of this week, the airports still had massive signs about foot-and-mouth disease and virtually nothing about SARS.
In these circumstances, panic becomes contagious. Governments, exposed yet again, get the heebie-jeebies and overcompensate with hyperactive impersonations of superheroes swinging boldly into action. Last time, we were all sent, at great expense, iodine tablets that would somehow ward off the radioactivity from a blown-up Sellafield. (How many of us have a clue where those supposedly vital tablets are now?) This time, the dearth of information was replaced with the other extreme of daily crisis briefings for the media.
Competent government is probably the best antidote to these panic attacks. But the rest of us could also show a bit more sense. We could, for example, make a point of visiting Chinese restaurants or sitting next to those nice Asian students on the bus. We could also remember that a bit of old-fashioned hygiene goes a long way. Using a handkerchief, washing your hands and not spitting out your chewing gum may seem rather mundane responses to a global panic. But if more of us tried them now and then, it might do more to keep us healthy than a daily dose of sensationalism.