Woolsorters’ Disease

Hugh Pennington

The big puzzle about anthrax is that terrorists have so far used it so little. After all, the bulk of the world’s population lives in countries where it occurs naturally, and where it isn’t difficult to get live material to start a culture. The notion that you need to be trained in biological warfare to grow it is ludicrous. In principle, any doctor, dentist, vet, microbiology graduate or hospital bacteriology lab technologist could produce it. In Britain, at least 100,000 people have the knowledge, and even if they’ve forgotten some of it, they know which textbook contains the necessary details. Preparing spores is easy: biological warfare researchers used to grow them on Marmite agar, which incorporated that well-known yeast extract. ‘Weaponising’ the spores isn’t difficult either. It’s true that something has to be added to spore suspensions to stop them clumping when they are prepared and dried, but as David Henderson from Porton Down said in 1952, in a journal to be found in any medical school library, ‘fortunately many substances added to the suspension will prevent clumping. The simplest and most effective that has been found is sodium alginate used in concentrations of about 0.1 per cent.’ Laboratory-quality sodium alginate costs £42 per half-kilo – enough to treat 200,000 billion spores – and is available from laboratory suppliers. It comes from seaweed and is widely used in the food industry – in ice cream, for example, to stop ice crystals forming.

Scientists optimise their chances of making a discovery by picking on problems that are ripe for resolution, often because the necessary laboratory techniques have just come on stream. Robert Koch’s choice of anthrax in 1873 is a brilliant instance of this. Thanks to anthrax, he founded bacteriology as a science and in little over a decade catapulted himself from the life of a rural doctor in a small town in Posen – a province of the Second Reich east of the Oder described in the contemporary Baedeker as ‘uninteresting’ – to a chair and institute directorship at the University of Berlin and, eventually, a Nobel Prize. His choice was inspired for the same reason that anthrax is so amenable to use by terrorists: growing it is not a sophisticated undertaking. Koch made his own glass culture chambers and filled them with liquid taken from inside the eyes of cattle killed at his local slaughterhouse. The bacteria grew beautifully and made spores. To test the virulence of his cultures he used wild mice from the stables, then white mice from the small but rapidly breeding colony kept as pets by his daughter. He made his own constant temperature incubator by carefully adjusting the height of a kerosene flame under the dishes of sand on which his cultures rested.

Koch invented these methods as he went along because other equipment wasn’t commercially available; and since he didn’t have a laboratory, he carried out the experiments in his consulting room. The room faced south-west, and the sun provided the light for his microscope. He worked alone. His first paper on anthrax, ‘Die Aetiologie der Milzbrand-Krankheit, begründet auf die Entwicklungsgeschichte des Bacillus Anthracis’, was published in 1876, and was recognised by the scientific community for the masterpiece it was. For the first time there was incontrovertible evidence that a specific disease was caused by a specific organism. The paper described his discovery of anthrax spores – the extremely resistant but still infectious stage of the bacterium’s life history which allowed it to survive harsh environments and stay in the soil for years as a threat to farm animals. If Koch could do all these things with home-made apparatus, there is surely nothing to prevent a contemporary terrorist, with the results of more than a hundred years of research on anthrax at his disposal, from setting up a spore factory and scaling up the procedure.

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