Infectious diseases have long been the companions of war and natural disaster. For those that barely escaped death in the calamities of antiquity, walking away with what appeared to be a light injury, the agony of a gangrenous wound or convulsive, back-breaking muscle spasms would deal an impending final blow. For centuries, a dreaded complication from an innocent blister or a bullet wound was the untreatable and catastrophic tetanus, caused by Clostridium tetani.
Clostridium tetani resides in the environment, forming spores amidst soil and leaves. It is everywhere: it can be found in a thimbleful of loamy soil pulled from the ground of the southern United States, and it is just as much at home in the fetid muck of the jungles of southeast Asia. So long as it remains on the far side of our skins, and the borders of our bodies remain battened, we are safe. The moment our defenses are compromised, whether by the scratch of a rose thorn or a blister on the sole of a foot or a traumatic amputation, and tetanus-laden earth gains access to our the body, it is another matter altogether. Tetanus, in short, takes advantage of our carelessness.
