Re: Mesozoic illnesses

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

Dora Smith writes: 

> There's diseases everywhere. As a rule, we're more at risk for diseases 
> that evolved among mammals, or at least that are closely related to current 
> diseases among mammals.

Humans have caught (and died from) psittacosis. Salmanella bacteria also 
readily infect humans directly from birds. 

Human influenza also tends to come to us from birds, via pigs. H5N1 (AKA 
'bird flu') doesn't even need pigs as an intermediary - although for all we 
know it may have re-infected birds after spending time in mammals (I seem to 
remember a mass-culling of civet cats when they were found to have H5N1 
antibodies). Once a virus jumps a species barrier, it is more likely to be 
able to infect more species still. Here in Australia we've had people die 
from a virus caught from horses (which in turn seem to have caught it from 
flying foxes). 

As a general rule though, most viruses tend to be specific to certain animal 
groups. Bacteria however tend to be more flexible, and fungi are rarely 
picky at all. 

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Dann Pigdon
GIS / Archaeologist              geo cities.com/dannsdinosaurs
Melbourne, Australia             heretichides.soffiles.com
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