Dr James Le Fanu: flu virus
Here's a germ of an idea.
500 bacterial species are believed to be living on our skin (New York University)
100 trillion the number of bacteria cells in our digestive system at any one time (www.typesofbacteria.co.uk )
3 the number of days after being exposed to a cold virus that people are thought to be most contagious (www.kidshealth.org)
Further, we are all, if paradoxically, deeply indebted to the flu virus and the tens of thousands of types of germs, fungi and bacteria that have caused so much human misery over the centuries. Specifically, their remarkable ability to spread themselves around and adapt to different environments is indispensable to the existence of all higher forms of life, including ourselves.
They are essential for all our food requirements: fixing nitrogen in the soil on which the growth of all our staple crops depend on; and facilitating the breakdown of indigestible cellulose in the stomachs of cows, sheep and goats. Yeasts convert sugar to alcohol and carbon dioxide, giving us bread, wine and beer, while the fungus penicillium is the main ingredient of Stilton and Gorgonzola. Thus a meal of steak, chips and salad and a glass of wine is completely germ-dependent. As indeed is its digestion which would generate litres of methane and hydrogen gases that would cause us to pass wind almost continuously – without the tens of millions of bacteria in our guts that convert them into non-volatile substances.
In the cycle of life, growth is balanced by decay and the ability of germs to recycle organic waste “makes a massive contribution to global cleansing” as the eminent science writer Dr Bernard Dixon observes. “They attack the cocktail of filth that arrives in an unceasing stream at sewage disposal plants, rendering it safe and innocuous, sufficiently pure to be discharged into the cleanest of rivers.”
Thus, the harm that germs cause man is an almost inevitable corollary of their ability to do good. And for all that they are the simplest forms of life, their powers of survival far outstrip our own. They have been around for some 3,500 million years compared to just the 100,000 or so of homo sapiens and will continue to colonise the planet for aeons of time after we are gone. They command our respect.