"Brian Sandle" wrote in message
...
Where is there any evidence of this. I think you are
getting carried away with the classifications again. If you run out
of
hosts
you just find more

Jump species? You would have to do that before you killed every last
one of the previous species.

which isn't a problem, those who prey on only one species are very much
a
minority

Lots of viruses tend to be specific to certain classes of hosts.

yes, classes of hosts are normally groups of species


Calici haemorrhagic disease jumped to rabbits in 1970s in China, though I
don't know why.


it is comparatively regular occurrance. I don't think I have heard of a
single virus, bacteria or other parasite which has become extinct due to the
extinction of its sole prey species.

Jim Webster