Sunday, 18 October 2009

outbreak #2

Everyone's heard about the Ebola and Marburg viruses, and some have been unfortunate enough to have seen Outbreak. Swine flu, as the latest candidate for becoming a pandemic, is scaring plenty more people. Most of whom might say, if asked to guess, that it came out of the bowels of Africa like Ebola did. Americans who've seen the film will come on top of that list - mysterious disease starts in Africa and ends up wiping out California. While this might make for a scary movie, it's quite possible that the next big outbreak will go the other way - from the darkest heart of California to end up killing people in Africa.
 Here's why: the meat industry in the US of A regularly pumps all its livestock full of antibiotics to prevent outbreaks due to the crowded conditions of their (for want of a better word) farms. This exerts an evolutionary pressure toward the formation of a drug-resistant strain of a common potentially-deadly-but-treatable disease.* 
 The US or Western Europe, where most of these factory-farms are based, are wealthy, well nourished and have relatively efficient governments that are capable of responding effectively to a pandemic. Some states in Africa on the other hand have no government to speak of, and a malnourished pop. thousands of whom live, bathe and eat in close proximity in slums (and boarding schools which are slightly cleaner). This is also what happens in parts of India.
 Also, I'd assume that most of the drugs given to meat-factory cows are the older generics, the sort you get in Africa or India, not the latest available for citizens of the US or the richer European countries. Thus it is badly managed, over-densely-populated Africa (or India) that is most at risk from the next superbug.
 All this is thanks to a nicer, better researched article in Wired. 


* You might say, this is to prevent outbreaks so why's it a bad thing?
 It's for the same reason that doctors do not require you to take a full complement of everything on the medicine shelf. Apart from making your life miserable, this will speed up the evolution of bacteria and viruses that are resistant to all the drugs you take. It's logical, even tautological: only the bugs that are capable of living in these conditions will thrive, resulting in what the media call drug-resistant superbugs.
 You might then ask 'why is it less likely that such a superbug might evolve in normal circumstances?'.
 For two reasons. First, antibiotics: when you get sick you take a full course of medicines strong enough to make you feel that it'll kill you. This generally wipes out said bug before it has a chance to evolve into something resistant. In a cow factory however, there might be more laxity in terms of control on dosage and there'll be tons of mildly drugged cowdung which could act as a playpen for our bugs to realise their full potential.
 Second, antibiotics: it suppresses the immune system, making the temple of your body something that anything can walk into by killing all the guards. But then why is something that happens in an immunologically suppressed cow dangerous for us?
  This time the answer is numbers. If these cows fill up with a drug resistant bug until they explode, there's more entries in the lottery that might end up as something winningly virulent that can be transferred to other cows, dogs or humans.
 This might also happen in a normal cow, but then the cow's immune system is more likely to nip the nascent pandemic in the bud, and like so many rock acts with real talent, we'd never get to hear of it.
 One could go into this in greater depth, but Doctors Agree healthy people taking mild doses of a drug for a prolonged period is definitely a bad thing, and if you want sources you can Google it like everyone else.

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