scrapie


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scrapie:

see prionprion
, abnormal form of a protein found in mammals, believed to cause a group of diseases known as prion diseases or transmissible spongiform encephalopathies. Well-known prion diseases are Creutzfeldt-Jakob disease (CJD) and kuru in humans, scrapie in sheep, bovine
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Scrapie

 

a slowly developing infectious disease of sheep that is associated with degenerative changes in the central nervous system and characterized by excitability, severe itching, paralysis, and emaciation. First reported in Great Britain in 1732, scrapie is recorded today in Europe, southern Africa, India, Australia, Canada, the USA, and many other areas.

The nature of the causative agent of scrapie has not been determined. A viral hypothesis has been formulated but not substantiated. Some believe the causative agent to be a protein, whereas others believe it to be a special type of polysaccharide. There also is a membrane hypothesis, which states that the biological activity of the causative agent of scrapie is the function of a modified cell membrane.

The causative agent of scrapie is extraordinarily resistant; it can withstand boiling for three hours, is resistant to chemical agents, and preserves well in desiccated pathological material and at low temperatures. Sheep 18 months of age and older are affected. The causative agent is transmitted when sick and healthy animals are housed together and when animals graze on infected pastures. Sheep of various breeds have different susceptibilities to scrapie. Although the disease has been recorded year-round, it occurs more frequently in winter and spring. Scrapie might be related to such human diseases as multiple sclerosis and parkinsonism. The incubation period lasts one to four years. At first, infected animals are characterized by unusual behavior, increased excitability, tremors, and an abnormal gait. Itching is also a characteristic early symptom. Subsequent symptoms include emaciation, incoordination, and paralysis. The animals die several weeks after the appearance of the first symptoms.

Scrapie is diagnosed according to clinical symptoms and histological examination. A treatment has not been developed. Control and preventive measures include the refusal of entry of sheep from an infected country and the slaughter of infected flocks. Some sheep breeders discontinue hereditary lines of sheep among which scrapie has been discovered.

REFERENCES

Kukhto, A. F. “Pochesukha ovets: skreipi.” In Bolezni ovets. Moscow, 1963.
Andrewes, C. Virusy pozvonochnykh. Moscow, 1967. (Translated from English.)
Andrewes, C. Estestvennaia istoriia virusov. Moscow, 1969. (Translated from English.)

I. A. BAKULOV

scrapie

[′skrā·pē]
(veterinary medicine)
A transmissible, usually fatal, virus disease of sheep, characterized by degeneration of the central nervous system.
References in periodicals archive ?
Selective breeding for genetic resistance to the disease is a valuable tool for the National Scrapie Eradication Program.
Prof Stanley Prusiner, who won the Nobel Prize for his research into prions, the protein agents thought to spread BSE and similar diseases, has produced the cow illness in genetically engineered mice infected with sheep scrapie.
Not scrapie positive, high-risk, or exposed animals
In reality the industry in northern England might have more to fear as vets dealing with the outbreak of foot and mouth disease have discovered scrapie is much more widespread in the region's flocks than previously recognised.
Scrapie goes back for years and as far as I know, there's no link between scrapie and human health.
Given the wide phenotypic variance of scrapie in sheep and our limited knowledge of this variance in goats, the D-IHC result on its own was insufficient for an unequivocal diagnosis.
In a second development, a new control protocol will be prepared on the issue which has to be submitted to EFSA by the end of May, which will then be implemented in Cyprus, providing more evidence is collected confirming the genetic resistance of goats to scrapie.
This is because some rare breeds show high levels of scrapie susceptible genotypes, and the WAG has made a commitment to conserve biodiversity.
We are pleased to broaden the availability of what we believe to be the most robust, widely-used assay in the world for scrapie susceptibility genotyping," said David Hartshorne, commercial director of Orchid Europe.
These include Nor98 or atypical scrapie in sheep (1) and 2 prion diseases of cattle, bovine amyloidotic spongiform encephalopathy or L-type BSE (2) and H-type BSE (3), both of which have a pathology and epidemiology distinct from classical or C-type BSE (4).
The Prionics[R]-CHECK PrioSTRIP SR detected EU reference samples of classical and atypical scrapie in sheep and goats as well as BSE in sheep with a sensitivity and specificity of 100%.
The approved scrapie programme for the years 2009 and 2010 submitted by Cyprus will receive special support, including a 75 per cent level of EC contribution to the compensation paid to the owners by the Government of Cyprus as well as costs for personnel and the destruction of carcasses.