SCRAPIE-lnfected Flocks Reported 



1947-59 



78 Flocks 

 21 States 



Fiscal Year 



NE9CO(rO)-sl29 



Cooperative scrapie eradication 



The cooperative eradication proj^ram is 

 based on procedures long used to eradicate 

 other diseases, with modifications required by 

 the unusual nature of scrapie. Prompt report- 

 ing of suspicious cases is stressed. 



Tentative clinical diagnosis is confirmed by 

 histopathological studies of brain tissues. Sus- 

 pect animals are maintained under observation 

 and are slaughtered until symptoms are fully 

 developed. 



Scrapie in other countries 



In August 1959, the Canadian Scrapie eradi- 

 cation program was broadened so that Canada 

 and the United States, whose regulatory offi- 

 cials had worked closely, now have equivalent 

 programs. Canadian oflficials have given assur- 

 ance that sheep which would have been slaugh- 

 tered under the current program, had it been 



in eff'fct in April 1957, will not be certified for 

 export to the United States. 



Australia and New Zealand — where it is be- 

 lieved scrapie had been newly introduced by 

 imported sheep — also instituted an eradication 

 program. Officials in both countries believe 

 their efforts to eradicate scrapie have been suc- 

 cessful. One outbreak among imported sheep 

 in Norway is l)eing similarly handled. 



In certain countries where .scrapie is en- 

 demic, owners attempt to reduce the incidence 

 of the disease and the .stigma of having an in- 

 fected Hock by slaughtering selected animals of 

 certain bloodlines. These do not represent or- 

 ganized efforts to eradicate the disease. 



Infected flocks and source flocks are quaran- 

 tined. All .sheep and goats in such flocks are 

 slaughtered under supervision at authorized 

 slaughtering plants. E.xpo.sed animals moved 

 from these flocks and their immediate progeny 

 are slaughtered. Premi.ses and vehicles are 

 cleaned and disinfected. 



Principles of eradication 



Research efforts to produce a vaccine to in- 

 crease resistance have been discouraging. If 

 either breed resistance or individual animal re- 

 sistance exists, it might be possible to develop 

 strains of scrapie-resistant sheep. Even if pos- 

 sible, this would be a long and laborious under- 

 taking. 



Preventing exposure of susceptible sheep is 

 the only method now known of avoiding addi- 

 tional outbreaks. Until research proves conclu- 

 sively whether scrapie spi-eads from parent to 

 oflFspring, or by some form of contact, any ef- 

 fective program must follow appropriately 

 modified conventional methods which embrace 

 both possibilities of .spread. 



Since the agent is known to exist in visibly 

 affected sheep, it is clear that they mu.st be de- 

 stroyed. There is no diagnostic test for the 

 disease in an animal not showing symptoms; 

 consequently, there is no way of knowing how 

 many exposed animals may harbor the infec- 

 tious agent. This factor, linked with the long 

 incubation period, necessitates the slaughter 

 of all exposed animals. 



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