In article <9O1g7CIh$P$$EwqZ@btopenworld.com>,
Oz <acoohdb@btopenworld.com> wrote:
Del Crow <delcrow@uniserve-dot-com.no-spam.invalid> writes
Apparently deer farms have discovered that the soil can harbor prions
and there is resulting spongiform encephalitis. Now, this is not
necessarily an additional way how BSE might be spread, but biowaste
is a concern.
Indeed, scrapie being believed to work similarly.
Only one piece of work ever done on prion biodegradeability in soil
showed a 1000-100,000 reduction in three years.
For bse, which is barely infective, this seems to be more than enough to
make soilborn transmission to cattle so rare it hasn't been seen.
For highly susceptible species/genotypes (eg for scrapie), it doesn't
appear to be enough and transmission appears to have occurred.
I reaall reading in a section of a book on "slow virus" and "viral
particle" that many years (I can't remember how many) after a scrapie
herd of sheep were slaughtered and removed from a pasture a new herd
became infected. This may be what is going on in wild and domesticated
deer in the US, a real mystery that MS Veneman of the USDA obviously
doesn't want to speak about.
On Jan 6 2004 an article "With Diseased Animals, Disposal Isn't Simple"
appeared in the NY Times on a company, "Waste Reduction with Waste
Reduction" that buids digesters, vats of lye that process carcases at
300 degrees F that it claims will "destroy prions" and liquify a 1,500
lb cow in eight hours, producing 76 lbs of bone and teeth remnants,
which can be used as fertilizer, 375 gallons of sterile solution of
water containing sugars, soaps and molecules that are the building
blocks of proteins. The company claims the non jelling liquid which has
a soap-like odor can be safely dumped into a sanitary sewer.
The companymakes vessels that can hold up to 10,000 lbs enough to digest
several carcases at once at a cost of aprox $1 million US with a water
system and hoists bringing the cost up another $.5 million US. The
company reportedly has proposed digestors that could hold 20,000 to
40,000 lb digestors to dispose of the brain, spinal and intestinal
tissue that is no longer allowed in the [human] meat supply.
About 30-40 digestors are in use through out the US nad and 5 are on
order for veteranary schools. The company is growing rapidly: in 2003
the rate was three or four times the previous year. "We expect the
coming year to triple again" a spokesperson said.
The reason for the growth has not been mad cow disease but the increase
in chronic wasting disease in deer and elk in the West and he Mid West.
It would seem from the above that there is lot of activity going on
behind the scenes in the US.
The otherwise excellent article makes one statement which seems to me to
be still open to question, "...given that animals and people can
contract mad cow disease by ingesting infected tissue ...
Best wishes,
Jim Scanlon
