
04/04/07, 01:40 PM
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Banned
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Join Date: Jul 2006
Location: N. Calif./was USDA 9b before global warming
Posts: 4,596
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Yeah, it sucks if you're a poultry farmer and they need to cull to keep it from rampaging through the nation's flocks. But being low path this one has only a moderate kill rate among chickens; it reduces the speed at which broilers gain weight and throws off egg-laying, so its impact is economic if it gets loose rather than in actually killing birds--it just makes them economically unviable.
Low path forms of flu can become high path when they encounter large numbers of naive new hosts, as can happen on a mega-farm. In that situation, the fastest virus is the 'winner' in the virus-vs-virus competition to infect the most hosts, and so the situation selects for the nastiest strains over the weaker ones. This is the other reason that even low path flu results in a cull of poultry--even when the flu doesn't readily cross species to affect humans. If it hits a big enough collection of birds to infect it can become high-path in birds.
I bet the pathologists were sweating bullets when they got that H5 data back; it usually takes longer to get the N moiety identified.
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