On Sat, 19 Jul 2003 12:19:01 +0100, Oz
wrote:


Because it's dominant in animals and third world countries.
Bacteria are a continual challenge.
Viruses are only successful when they find an immunologically naive
organism, which is quite hard without movement between distant
populations.

Yep, I follow that, thanks. Modern hygiene is cutting out so many
subclinical bacterial challenges.

Sorry, how do you know bacterial challenge was dominant over these
years? There is lots of vestigial organelle evidence for viral
invasions over the aeons.

I never said viruses didn't exist. They did and do. I said for most wild
populations bacteria offer a continual challenge, not viruses which tend
to be rare and sporadic.

Hokay, Thanks.

And I'd assumed it was ever thus. I would guess that antibiotics have
had close to zero effect on bacteria. Do you know of any that have
gone extinct?

The main human pathogens (ie they make people very ill) are very rare.
Remember that before antibiotics hospitals were predominantly filled
with bacterially infected people. The 'fever wards'.

I'm not sure. I can name smallpox, influenza, poliomyelitis, measles,
yellow fever, dengue fever, HIV, herpes, hepatitis A,B,C,D,E,F,G,
rabies, psittacosis, mumps, many gastrointestinal infections,
mononucleosis, and many other "fevers" and so on. Not sure of the
numbers though. You may be right

Yes, but I probably get mild bacterial infections of the gut every
couple of weeks, and for sure when walking and working in cow slurry I
must be getting a substantial bacterial challenge. Remember that a
challenge that is 'dealt with' is still a challenge and the immune
response is triggered even if no serious (or even observable) illness
results.

Of course. Same with viri

Indeed, however most viruses are highly species-specific, most bacteria
are not. ECO157 can happily move from cow to person whilst BVD cannot.
So typically bacteria get a bit of a permanent toehold moving between
species whilst viruses typically exist at very low level in an
immunologically resistant population and only get to attack each
individual once.

Tell that to shingles sufferers and my herpes simplex and flu and
colds
But I hear what you say, thanks.