Re: H1N5 (and Bakker's virus extinction hypothesis) now H5N1

[Dann Pigdon <dannj@alphalink.com.au>]

On Sun, 14 May 2006 14:03:56 +0000 (pd), Phil Bigelow wrote
> On Sun, 14 May 2006 20:49:34 +0200 Tommy Tyrberg writes:
> > Plague then stayed active around the Mediterranean until 
> > about 
> > 750, after which it disappeared, not to return until 1347,
> 
> A.D. 1347 is, very roughly, shortly after the beginning of the 
> "Little Ice Age".
> 
> > and once 
> > again 
> > disappearing (from Europe at least) in the eighteenth century.
> 
> Which is, very roughly, around the end of the "Little Ice Age".
> 

This is of no surprise, since apparently the fleas that spread BP to humans 
only do so below a certain temperature threshold. Above that threshold the 
fleas can continue to feed off rats with no trouble. Below a certain 
temperature, the plague pathogen causes clotting in the gut of the flea, 
causing it to slowly starve to death no matter how much it tries to feed. In 
this situation the flea is more likely to feed off any animal (rather than 
their usual target species) out of sheer desperation. Healthy fleas usually 
prefer feeding on only one specific host species.

So the lower the temperature gets, the more likely infected fleas are to try 
feeding on human blood (or so the theory goes).

--
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Dann Pigdon
GIS / Archaeologist         http://heretichides.soffiles.com
Melbourne, Australia        http://www.geocities.com/dannsdinosaurs
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