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Does Any Body Know?

Mike

Well-known member
About the cattle BSE/Scrapie experiments in Mission, Texas in 1979?

I have always thought that this affliction started in the UK in 1981.


The 1979 video clip of sheep-to-cow was from an exeriment in Mission, Texas. It apparently has never been made public before and was obtained under Freedom of Information Act but the results were no 'secret.' The program made clear that transmission was from [intra-cerebral] injection and not from feed. Brain tissue from the infected Mission cattle were later injected into other cattle to determine if second passage was possible, with positive results. The 1979 experiment is discussed in later publications by the Cutlip-Robinson group, relevent abstracts below.
 
A

Anonymous

Guest
Mike said:
About the cattle BSE/Scrapie experiments in Mission, Texas in 1979?

I have always thought that this affliction started in the UK in 1981.


The 1979 video clip of sheep-to-cow was from an exeriment in Mission, Texas. It apparently has never been made public before and was obtained under Freedom of Information Act but the results were no 'secret.' The program made clear that transmission was from [intra-cerebral] injection and not from feed. Brain tissue from the infected Mission cattle were later injected into other cattle to determine if second passage was possible, with positive results. The 1979 experiment is discussed in later publications by the Cutlip-Robinson group, relevent abstracts below.


I know flounder has posted several references to it- I had never heard of it before that... Heres one of his posts I found doing a search:

3.57 The experiment which might have determined whether BSE and scrapie were
caused by the same agent (ie, the feeding of natural scrapie to cattle) was
never undertaken in the UK. It was, however, performed in the USA in 1979,
when it was shown that cattle inoculated with the scrapie agent endemic in
the flock of Suffolk sheep at the United States Department of Agriculture in
Mission, Texas, developed a TSE quite unlike BSE. 32 The findings of the
initial transmission, though not of the clinical or neurohistological
examination, were communicated in October 1988 to Dr Watson, Director of the
CVL, following a visit by Dr Wrathall, one of the project leaders in the
Pathology Department of the CVL, to the United States Department of
Agriculture. 33 The results were not published at this point, since the
attempted transmission to mice from the experimental cow brain had been
inconclusive. The results of the clinical and histological differences
between scrapie-affected sheep and cattle were published in 1995. Similar
studies in which cattle were inoculated intracerebrally with scrapie inocula
derived from a number of scrapie-affected sheep of different breeds and from
different States, were carried out at the US National Animal Disease Centre.
34 The results, published in 1994, showed that this source of scrapie agent,
though pathogenic for cattle, did not produce the same clinical signs of
brain lesions characteristic of BSE.

http://www.bseinquiry.gov.uk/report/volume2/chaptea3.htm#820543


The findings of the initial transmission, though not of the clinical or
neurohistological examination, were communicated in October 1988 to Dr
Watson, Director of the CVL, following a visit by Dr Wrathall, one of the
project leaders in the Pathology Department of the CVL, to the United States
Department of Agriculture. 33


http://www.bseinquiry.gov.uk/files/yb/1988/10/00001001.pdf


http://www.bseinquiry.gov.uk/report/volume2/chaptea3.htm#820546
 

flounder

Well-known member
Gerald Wells: Report of the Visit to USA, April-May 1989

snip...

The general opinion of those present was that BSE, as an
overt disease phenomenon, _could exist in the USA, but if it did,
it was very rare. The need for improved and specific surveillance
methods to detect it as recognised...

snip...

It is clear that USDA have little information and _no_ regulatory
responsibility for rendering plants in the US...

snip...

3. Prof. A. Robertson gave a brief account of BSE. The US approach
was to accord it a _very low profile indeed_. Dr. A Thiermann showed
the picture in the ''Independent'' with cattle being incinerated and thought
this was a fanatical incident to be _avoided_ in the US _at all costs_...

snip...

http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

To be published in the Proceedings of the
Fourth International Scientific Congress in
Fur Animal Production. Toronto, Canada,
August 21-28, 1988

Evidence That Transmissible Mink Encephalopathy
Results from Feeding Infected Cattle

R.F. Marsh* and G.R. Hartsough

•Department of Veterinary Science, University of Wisconsin-Madison, Madison,
Wisconsin 53706; and ^Emba/Creat Lakes Ranch Service, Thiensville, Wisconsin 53092

ABSTRACT
Epidemiologic investigation of a new incidence of
transmissible mink encephalopathy (TME) in Stetsonville, Wisconsin
suggests that the disease may have resulted from feeding infected
cattle to mink. This observation is supported by the transmission of
a TME-like disease to experimentally inoculated cattle, and by the
recent report of a new bovine spongiform encephalopathy in
England.

INTRODUCTION

Transmissible mink encephalopathy (TME) was first reported in 1965 by Hartsough
and Burger who demonstrated that the disease was transmissible with a long incubation
period, and that affected mink had a spongiform encephalopathy similar to that found in
scrapie-affecied sheep (Hartsough and Burger, 1965; Burger and Hartsough, 1965).
Because of the similarity between TME and scrapie, and the subsequent finding that the
two transmissible agents were indistinguishable (Marsh and Hanson, 1969), it was
concluded that TME most likely resulted from feeding mink scrapie-infecied sheep.
The experimental transmission of sheep scrapie to mink (Hanson et al., 1971)
confirmed the close association of TME and scrapie, but at the same time provided
evidence that they may be different. Epidemiologic studies on previous incidences of
TME indicated that the incubation periods in field cases were between six months and
one year in length (Harxsough and Burger, 1965). Experimentally, scrapie could not be
transmitted to mink in less than one year.
To investigate the possibility that TME may be caused by a (particular strain of
scrapie which might be highly pathogenic for mink, 21 different strains of the scrapie
agent, including their sheep or goat sources, were inoculated into a total of 61 mink.
Only one mink developed a progressive neurologic disease after an incubation period of
22 mon..s (Marsh and Hanson, 1979). These results indicated that TME was either caused
by a strain of sheep scrapie not yet tested, or was due to exposure to a scrapie-like agent
from an unidentified source.

OBSERVATIONS AND RESULTS

A New Incidence of TME. In April of 1985, a mink rancher in Stetsonville, Wisconsin
reported that many of his mink were "acting funny", and some had died. At this time, we
visited the farm and found that approximately 10% of all adult mink were showing
typical signs of TME: insidious onset characterized by subtle behavioral changes, loss of
normal habits of cleanliness, deposition of droppings throughout the pen rather than in a
single area, hyperexcitability, difficulty in chewing and swallowing, and tails arched over
their _backs like squirrels. These signs were followed by progressive deterioration of
neurologic function beginning with locomoior incoordination, long periods of somnolence
in which the affected mink would stand motionless with its head in the corner of the
cage, complete debilitation, and death. Over the next 8-10 weeks, approximately 40% of
all the adult mink on the farm died from TME.
Since previous incidences of TME were associated with common or shared feeding
practices, we obtained a careful history of feed ingredients used over the past 12-18
months. The rancher was a "dead stock" feeder using mostly (>95%) downer or dead dairy
cattle and a few horses. Sheep had never been fed.

Experimental Transmission. The clinical diagnosis of TME was confirmed by
histopaihologic examination and by experimental transmission to mink after incubation
periods of four months. To investigate the possible involvement of cattle in this disease
cycle, two six-week old castrated Holstein bull calves were inoculated intracerebrally
with a brain suspension from affected mink. Each developed a fatal spongiform
encephalopathy after incubation periods of 18 and 19 months.

DISCUSSION
These findings suggest that TME may result from feeding mink infected cattle and
we have alerted bovine practitioners that there may exist an as yet unrecognized
scrapie-like disease of cattle in the United States (Marsh and Hartsough, 1986). A new
bovine spongiform encephalopathy has recently been reported in England (Wells et al.,
1987), and investigators are presently studying its transmissibility and possible
relationship to scrapie. Because this new bovine disease in England is characterized by
behavioral changes, hyperexcitability, and agressiveness, it is very likely it would be
confused with rabies in the United Stales and not be diagnosed. Presently, brains from
cattle in the United States which are suspected of rabies infection are only tested with
anti-rabies virus antibody and are not examined histopathologically for lesions of
spongiform encephalopathy.
We are presently pursuing additional studies to further examine the possible
involvement of cattle in the epidemiology of TME. One of these is the backpassage of
our experimental bovine encephalopathy to mink. Because (here are as yet no agent-
specific proteins or nucleic acids identified for these transmissible neuropathogens, one
means of distinguishing them is by animal passage and selection of the biotype which
grows best in a particular host. This procedure has been used to separate hamster-
adapted and mink-udapted TME agents (Marsh and Hanson, 1979). The intracerebral
backpassage of the experimental bovine agent resulted in incubations of only four months
indicating no de-adaptation of the Stetsonville agent for mink after bovine passage.
Mink fed infected bovine brain remain normal after six months. It will be essential to
demonstrate oral transmission fiom bovine to mink it this proposed epidemiologic
association is to be confirmed.

ACKNOWLEDGEMENTS
These studies were supported by the College of Agricultural and Life Sciences,
University of Wisconsin-Madison and by a grant (85-CRCR-1-1812) from the United
States Department of Agriculture. The authors also wish to acknowledge the help and
encouragement of Robert Hanson who died during the course of these investigations.

REFERENCES
Burger, D. and Hartsough, G.R. 1965. Encephalopathy of mink. II. Experimental and
natural transmission. J. Infec. Dis. 115:393-399.
Hanson, R.P., Eckroade, R.3., Marsh, R.F., ZuRhein, C.M., Kanitz, C.L. and Gustatson,
D.P. 1971. Susceptibility of mink to sheep scrapie. Science 172:859-861.
Hansough, G.R. and Burger, D. 1965. Encephalopathy of mink. I. Epizoociologic and
clinical observations. 3. Infec. Dis. 115:387-392.
Marsh, R.F. and Hanson, R.P. 1969. Physical and chemical properties of the
transmissible mink encephalopathy agent. 3. ViroL 3:176-180.
Marsh, R.F. and Hanson, R.P. 1979. On the origin of transmissible mink
encephalopathy. In Hadlow, W.J. and Prusiner, S.P. (eds.) Slow transmissible
diseases of the nervous system. Vol. 1, Academic Press, New York, pp 451-460.
Marsh, R.F. and Hartsough, G.R. 1986. Is there a scrapie-like disease in cattle?
Proceedings of the Seventh Annual Western Conference for Food Animal Veterinary
Medicine. University of Arizona, pp 20.
Wells, G.A.H., Scott, A.C., Johnson, C.T., Cunning, R.F., Hancock, R.D., Jeffrey, M.,
Dawson, M. and Bradley, R. 1987. A novel progressive spongiform encephalopathy
in cattle. Vet. Rec. 121:419-420.

MARSH

http://www.bseinquiry.gov.uk/files/mb/m09/tab05.pdf

TSS
 

mrj

Well-known member
Interesting........that transmission was via INJECTION.

Has there been any scientific controlled tests resulting in transmission, sheep to cattle, or cattle to cattle, via INGESTION?


MRJ
 

ranch hand

Well-known member
MRJ said:
Interesting........that transmission was via INJECTION.

Has there been any scientific controlled tests resulting in transmission, sheep to cattle, or cattle to cattle, via INGESTION?


MRJ

Then MRJ.....why does NCBA go along with the feed ban?
 

Mike

Well-known member
MRJ said:
Interesting........that transmission was via INJECTION.

Has there been any scientific controlled tests resulting in transmission, sheep to cattle, or cattle to cattle, via INGESTION?


MRJ

They call it "Orally Challenging". Yes there are several.

You must remember that injection of PrPsc into mice was the first BSE test.

Injecting is only a faster way to get the same results. With the long incubation periods associated with these diseases, had they not done many of these experiments this way, we would still be waiting on research started 10 years ago.
 

Mike

Well-known member
ranch hand said:
MRJ said:
Interesting........that transmission was via INJECTION.

Has there been any scientific controlled tests resulting in transmission, sheep to cattle, or cattle to cattle, via INGESTION?


MRJ

Then MRJ.....why does NCBA go along with the feed ban?

Every country in the world is hanging their hat on oral transmission.

It would be the biggest scandal the world has ever known should this idea be disproven.

Some of the research has shown that as little as .1 gram of homogenated (Mixed thoroughly) matter can transmit the disease to cattle while others might not be affected.
 

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