prions. cheese. mad cow disease. milk.

Bob xyzbbruner at uclink4.berkeley.edu
Wed Jan 7 23:10:27 EST 2004


On Wed, 07 Jan 2004 16:16:57 GMT, "Kyle Legate" <legatek at hotmail.com>
wrote:

>Louis Hom wrote:
>>
>> They primarily *affect* the brain and nervous system, but at least
>> some of the evidence suggests that the lymphatic system is involved in
>> transit of the prions and establishing the infection.  Can't comment
>> on the validity/seriousness of the implications of these results, but
>> it makes me at least a little nervous/squeamish.
>>
>I admit that I''m not up to date on the prion field, but the answers to two
>questions are not clear to me:
>
>1. Is there any evidence that eating contaminated meat can transfer the
>disease to humans?

For transmission between humans, definitely. The biggest epidemic of
prion disease in humans was due to cannibalism, specifically eating
the brains.

For transmission from cow to human, the circumstantial evidence from
Britain is rather strong.


>
>2. Considering that our digestive systems are efficient at digesting
>protein, and our intestinal epithelia take up peptide fragments and not
>whole proteins, how is it possible that the disease-causing form of PrP can
>make it into our bodies and incorporate into nerve tissue membranes intact?
>

This was discussed in another thread recently. I do not recall the
details, but there are plausible pathways. Maybe not efficient, but
enough to be a potential problem. The disease prion is a difficult
protein.


>Call me skeptical, but I'm not convinced that BSE is worth the fear.

What (kind/level of) fear? In the US, there is probably a very low
level of BSE, and there are substantial precautions to prevent
diseased tissue from getting into our food supply. I don't think an
American should worry much about getting BSE. But that is because we
are stopping it -- and are instituting even more stringent procedures
to control it further.

UK got caught without the knowledge we have, and 150 or so people have
died from it. The big concern is whether many many more are to come;
this type of disease often seems to have a very long incubation
period, so it is hard to know.

bob





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