Man is the only creature that can contemplate, and enjoy the contemplation of, his own extinction. One of the means by which he might disappear from the face of the earth, at least in the imagination of the writers of pulp fiction, is by the development, either by chance or design, of a fast-spreading and fatal new virus against which he has no resistance.
The emergence of bird flu fifteen years ago conjured up visions of a viral Armageddon. It was previously unknown and it was dangerous. It gave rise to the archetypal health scare, that is to say a panic about a remote possibility that was much more frightening than more real, constant but everyday dangers with which we are so familiar that we ignore them.
Bird flu was frightening because the case-fatality rate (the proportion of people who died having contracted the disease) was high and there was no treatment for it. Fortunately, though, its communicability from bird to man was low, and from person to person virtually unknown. According to a recent paper in The Lancet, 344 of 583 people known to have contracted it in the last 15 years died of it, a very tiny absolute number by comparison with the total numbers of deaths in the world during that period.
Is complacency then in order? The problem is that viruses mutate quickly; and theoretically a mutation could take place which permitted the bird flu virus first to spread more easily from bird to man, and then from person to person, in which case there could be a pandemic as large and fatal as that of the Spanish flu in 1918-1919 that killed more people than the First World War.
According to The Lancet, researchers have now genetically-engineered strains of bird flu that can pass easily from ferret to ferret (the animal model often used in flu research) by means of aerosol, that is to say by air exhaled from the lungs. This demonstrates the possibility that a bird flu virus could emerge that would threaten the health of mankind.
The first justification for deliberately engineering a bird flu virus that is easily transmitted from ferret to ferret is that it alerts the world to the potential hazard to public health posed by the virus, thus countering a dangerous complacency about it; the second is that it might aid attempts to produce a vaccine against or a treatment of the illness. But critics argue that the research actually increases the risks of disaster rather than reduces them, either by inadvertence or (if the technique for engineering viruses fell into the wrong hands) by malice.
The scientific journals that were to publish the research were faced with a dilemma. Should they, or should they not, omit information about the technique of engineering the virus? Did freedom trump caution? In the end, they decided to omit the information in the name of safety, but to give it to bona fide researchers who asked for it.
Of course the threat of a pandemic of a new and fatal viral disease would be a very blunt instrument for anyone who wanted to use it, because he could not insure himself or his friends against it. But perhaps there are enough nihilists in the world to make the danger a real one.
How worried, then, should we be by bird flu? I confess that I am not sure. And not knowing how anxious I ought to be makes me… well, anxious.