Transactions of RHASS Volume 1940 - Page 045
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| Year | 1940 |
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78 SCRAPIE. was reached within fourteen days after the first obServable signs of illness, but usually the malady is chronic in type and runs a course of six weeks to six months or longer before terminating in death. The course is of relatively shorter duration in those sheep which were in a debilitated condition at the time of attack, and the disease is believed to assume a more acute form in summer as compared with winter-time. In a few observed cases the course of the disease has been extraordinarily prolonged. In one case recorded by Stocknian death occurred eleven months after the first appearance of the disease. and the writer had a case under observation for fifteen months. These animals were, however, maintained at reSearch institutes under comparatively sheltered and generally favourable conditions. A case in which the courSe was remarkably prolonged. following the repeated administration to the affected animal of an essential oil. may be recorded here in some detail. Mr Lothian, Veterinary Surgeon, Duns. had informed the writer that in his experience the repeated administration of oil of turpentine to flocks in which the disease was prevalent appeared to possess some preventive value. and that in a few instances the administration of this drug to affected animals seemed to ameliorate the symptoms. Accordingly. on 19th November 1931, two ewes suffering from typical scrapie each received an emulsion containing oil of turpentine. The administration of the drug was repeated twice weekly for four months. “'ithin a few weeks after the commencement of treatment both sheep appeared to have improved in their general physical condition, but the symptoms of scrapie were still evident. Four months after the commencement of treatment one ewe died from a cause unconnected with the disease, and the treatment was then discontinued in the case of the other ewe. This ewe markedly improved in her physical condition. but the symptoms of pruritus, although less intense, still continued in evidence. The ewe became pregnant in November 1932, and in due course gave birth to a lamb which, however. died within a few days after birth. The ewe herself died from an undetermined cause on the 9th June 1933, that is about one year and Seven months after having been first placed under observation. One cannot say whether in this particular case the adminis- tration of oil of turpentine was responsible for the marked prolongation of the course of the disease, but this may not be without significaIICe, and it is proposed to investigate the matter further when opportunity offers. SCRAPIE. 79 ANATOMICAL CHANGES. In diseases which run a chronic course it is to be expected .hat definite gross tissue damage will result. In this respect «rapic presents a singular exception to the general rule, because, while the course is relatively protracted and the vmptoms become progressively intense until afatal termina- ion is reached, apart from the emaciation and the presence at such injuries as may have been induced by the vigorous rubbing of the skin, no gross pathological change occurs in .he disease. This view is shared by all investigators, and :he writer has himself carried out numerous systematic post— mortem examinations with entirely negative results. It should, however, be recorded here that in each of five scrapie nuns which Stockman examined there was found a catarrhal nzlit‘h. purple in colour, on the mucous membrane of the lrethra and extending some distance forward from the neck At the bladder. The possible significance of this lesion remains muletermined. Bertrand, Carre’, and Lucam obServed a lesion on the uterine» mucous membrane consisting in one or more plaques approximately 1 cm. to 2 cm. in diameter, md brown or brownish-black in colour; the lesion was I.resent in nine of ten scrapie ewes examined (90 per cent), \\ hile in one hundred and fifty presumably healthy ewes it was mlllid in nineteen instances (about 12 per cent). The possible significance of this lesion is also undetermined. MICROSCOPIC CHANGES. So long ago as 1898 Besnoit and Morel described in scrapie .Iertain changes in the medulla, spinal cord, large nerve trunks. 1nd peripheral nerves ; these changes included vacuolation of e't'l'izllll of the neurones (nerve cells) in the medulla and cord, and a degenerative inflammatory condition of the peripheral nerves. As a result of these findings Besnoit and More] suggested that the disease be named “ Nevrite périphérique <'llZ()0th118 du mouton.” Stoekman (1926), while noting the presence of vacuolation in the neurones, failed to confirm Besnoit and Morel’s observations upon the existence of a peripheral neuritis. Stockman also observed the presence of inclusion bodies in the neurones and in the cells of the spinal ganglia. These bodies in their staining reactions resembled the, so—called Negri bodies found in rabies, but whether they bear any relationship to the cause of scrapie is doubtful. Bertrand, Carré, and Lucam confirmed in general the observations of Besnoit and Morel and those of Stockman, but also failed to demonstrate a peripheral neuritis. They |
| Title | Transactions of RHASS Volume 1940 - Page 045 |
