NEW biological weapons are being created right this minute 鈥� though not in any secret laboratory or military base. Out of reach of international legislation, there is a genetic lending library of evil in action, and while you may not realise it, you are intimately involved. It鈥檚 been going on for millions of years, but we have only just begun to explore this sinister new territory. Welcome to the pathosphere.
What is the pathosphere? It is the surprisingly vast and growing gene pool in which pathogens, the microbes that cause disease, meet and mingle. 杏吧原创s have long known that the so-called plastic genome of many pathogens allows them to readily swap genes, transferring genetic material in information packages called plasmids. Now it seems they have access to a much broader supply of genes than previously believed. Frederick Blattner, a geneticist at the University of Wisconsin, Madison, named this genetic lending library the pathosphere 鈥� the realm that blurs the lines between pathogen species.
The pathosphere was unveiled in 2001 when researchers mapped the genome of the microbe Escherichia coli. They found a shocking number of differences between benign and vicious E. coli strains, suggesting that the strains can quickly acquire large amounts of new genetic material, not only from relatives within their species but from an alarmingly large range of bacteria. On the family level, a huge bank of genes is being shared among bacteria including salmonella (food poisoning), shigella (more food poisoning), yersinia (plague) and even plant bacteria.
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What鈥檚 so sinister about the pathosphere? Its existence means that pathogens are more closely connected than we thought. They are able to trade genes in bulk, and conspire to enhance one another鈥檚 survival skills. A relatively benign bacterium can survive an antibiotic attack, then hand over the genetic secrets of its success to more vicious pathogens.
鈥淭here is a genetic lending library of evil in action, and you are intimately involved鈥�
Right now, Hong Kong is battling a plague of antibiotic-resistant bugs, the result of heavy antibiotic use during the SARS epidemic. And just two weeks ago the UK鈥檚 Health Protection Agency reported a new variant of E. coli that is resistant to all but a few antibiotics.
Even worse, the pathosphere鈥檚 embrace is perpetually widening. Research discussed at last month鈥檚 meeting of the Society for Invertebrate Pathology in Alaska shows that some human pathogens acquire dangerous survival skills while hosted by invertebrate species. A spider鈥檚 saliva houses bacteria that can rot human flesh. With gene swapping occurring between vertebrates and invertebrates, the pathosphere ascends another rung of the ladder from family to order.
Should we be frightened? Definitely. As drug-resistant genes circulate in the pathosphere, new bioweapons are continuously produced. But on the bright side, the fact that pathogens once believed to be disparate are actually connected means that we could develop one knock-out solution and apply it to the central gene bank as a cure-all for a whole host of ills.
