*** Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie Experiment 1964 ***

*** How Did CWD Get Way Down In Medina County, Texas?

Confucius ponders...

Could the Scrapie experiments back around 1964 at Moore Air Force near Mission, Texas, could this area have been ground zero for CWD TSE Prion (besides the CWD cases that have waltzed across the Texas, New Mexico border near WSMR Trans Pecos region since around 2001)?

Epidemiology of Scrapie in the United States 1977


Scrapie Field Trial Experiments Mission, Texas

A Scrapie Field Trial was developed at Mission, Texas, to provide additional information for the eradication program on the epidemiology of natural scrapie. The Mission Field Trial Station is located on 450 acres of pastureland, part of the former Moore Air Force Base, near Mission, Texas. It was designed to bring previously exposed, and later also unexposed, sheep or goats to the Station and maintain and breed them under close observation for extended periods to determine which animals would develop scrapie and define more closely the natural spread and other epidemiological aspects of the disease.

The 547 previously exposed sheep brought to the Mission Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds. They were purchased as field outbreaks occurred, and represented 21 bloodlines in which scrapie had been diagnosed. Upon arrival at the Station, the sheep were maintained on pasture, with supplemental feeding as necessary. The station was divided into 2 areas: (1) a series of pastures and-pens occupied by male animals only, and (2) a series of pastures and pens occupied by females and young progeny of both sexes. ...

snip...see full text ;


Mission, Texas Scrapie transmission to cattle study

Wilbur Clarke (reference the Mission, Texas scrapie transmission transmission to cattle study) is now the State Veterinarian for Montana based at Helena.

I was given confidential access to sections from the Clarke scrapie-cattle transmission experiment. Details of the experimental design were as supplied previously by Dr. Wrathall (copy of relevant information appended). Only 3 animals (2 inoculated with 2nd pass Suffolk scrapie and 1 inoculated with Angora goat passaged scrapie) showed clinical signs. Clinical signs were characterised by weakness, ''a stilted hindlimb gait'', disorientation, ataxia and, terminally, lateral recumbency. The two cattle from which I examined material were inocluated at 8 months of age and developed signs 36 months pi (goat scrapie inoculum) and 49 months pi (one of the Suffolk scrapie inoculated) respectively. This latter animal was killed at 58 months of age and so the clinical duration was only 1 month. The neuropathology was somewhat different from BSE or the Stetsonville TME in cattle. Vacuolar changes were minimal, to the extent that detection REQUIRED CAREFUL SEARCHING. Conversely astrocyte hypertrophy was a widespread and prominent feature. The material requires DETAILED NEUROPATHOLOGICAL ASSESSMENT BUT WHETHER OR NOT THIS WILL BE DONE REMAINS A QUESTION.

Transmission Studies

Mule deer transmissions of CWD were by intracerebral inoculation and compared with natural cases {the following was written but with a single line marked through it ''first passage (by this route)}...TSS

resulted in a more rapidly progressive clinical disease with repeated episodes of synocopy ending in coma. One control animal became affected, it is believed through contamination of inoculum (?saline). Further CWD transmissions were carried out by Dick Marsh into ferret, mink and squirrel monkey. Transmission occurred in ALL of these species with the shortest incubation period in the ferret.


Appendix 3


1. Dr Clark lately of the Scrapie Research Unit, Mission Texas has successfully transmitted ovine and caprine scrapie to cattle. The experimental results have not been published but there are plans to do this. This work was initiated in 1978.

A summary of it is:-

Expt A

6 Her x Jer calves born in 1978 were inoculated as follows with

a 2nd Suffolk scrapie passage:-

i/c 1ml; i/m, 5ml; s/c 5ml; oral 30ml.

1/6 went down after 48 months with a scrapie/BSE-like disease.

Expt B

6 Her or Jer or HxJ calves were inoculated with angora Goat

virus 2/6 went down similarly after 36 months.

Expt C

Mice inoculated from brains of calves/cattle in expts A B were resistant, only 1/20 going down with scrapie and this was the reason given for not publishing.

Diagnosis in A, B, C was by histopath. No reports on SAT were given.

2. Dr Warren Foote indicated success so far in eliminating scrapie in offspring from experimentally- (and naturally) infected sheep by ET. He had found difficulty in obtaining embryos from naturally infected sheep (cf SPA).

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. BSE was not reported in USA.

4. Scrapie incidents (ie affected flocks) have shown a dramatic increase since 1978. In 1953 when the National Control Scheme was started there were 10-14 incidents, in 1978 - 1 and in 1988 so far 60.

5. Scrapie agent was reported to have been isolated from a solitary fetus.

6. A western blotting diagnostic technique (? on PrP) shows some promise.

7. Results of a questionnaire sent to 33 states on the subject of the national sheep scrapie programme survey indicated

17/33 wished to drop it

6/33 wished to develop it



Page 15 of 17

8/33 had few sheep and were neutral

Information obtained from Dr Wrathall's notes of a meeting of the U.S. Animal Health Association at Little Rock, Arkansas Nov. 1988.




Spongiform Encephalopathy in Captive Wild ZOO BSE INQUIRY



Sunday, June 12, 2016

TPWD Special Meeting Chronic Wasting Disease Response Rules June 20, 2016


kind regards, terry