Investigation into the disease of sheep called 'scrapie' (Traberkrankheit: la tremblante) with especial reference to its association with sarcosporidiosis.

  • M'Gowan, J. P.
Date:
1914
Catalogue details

Licence: In copyright

Credit: Investigation into the disease of sheep called 'scrapie' (Traberkrankheit: la tremblante) with especial reference to its association with sarcosporidiosis. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    zootiological facts about the disease, and so far as my experience goes in listening to the statements made by farmers, is war- ranted. When, however, the question is raised as to whether it is infectious as well as hereditary, or whether the disease is transmitted by the rams or by the ewes, great variation of opinion arises. As regards the contagiousness of the disease, up to the present, there is no evidence of such a condition exist- ing. Had it existed, with the sale broadcast of lambs from scrapie flocks, and of such ewes from the flocks as had survived till they were of age to be cast, the disease would now be widely spread. Such, however, is not the case. Again, the usual method of combating the disease, consisting in selling off the old ewes and buying in young sheep from clean flocks, renders such a view untenable; for here the diseased and healthy mingle freely with one another; and yet when the last of the diseased stock has been sold the disease has been stamped out. This has been the experience of several farmers with whom I have discussed the matter personally. Such a condition of affairs, again, negatives the idea that the infection hangs about a place, on the pasture, fences, &c. One view of the infection which I have heard canvassed is that it is on the ground, and the lambs pick it up. Lambs are specially noted because of the appearance of the disease at two to two and a half years. Possible heredity has been in the minds of those holding this view. Here again, however, the facts do not fit in with such a view, for there is no reason why, if such were the case, the lambs from scrapie mothers should be highly affected out of all proportion to the lambs from apparently healthy mothers, going on the same pasture, as my own observations on this subject show. We have already seen that a lamb born from a scrapie ewe will develop the disease, even if it is taken away at once from the mother and put on to a healthy sheep. Indeed this is the usual method of rearing the produce of scrapie ewes; and the instances of the occurrence mentioned are legion. While all the evidence, therefore, points to the non-contagiousness of the disease, for the sake of completeness let us examine an imaginary case where the disease appeared in a flock subsequent to the introduction into that flock of some diseased stock. Two points must be considered very carefully before the conclusion is arrived at that the diseased animals