It cannot be said that the horse is particularly subject to diseases which are propagated by contagion, but it is certainly the case that the animal is the victim of one malady which, from its insidious nature and the tenacity with which it clings to the premises in which it breaks out, will bear comparison with any of the plagues which affect the lower animals.
Glanders and farcy, or, more correctly, the one disease glanders, or in technical language equinia, which, according to its manifestation in different parts of the body, is distinguished by one or the other term, has a very wide distribution and a history which is lost in the lapse of time. It was known as far back as available records extend. According to an article which was published in Vol. VI, Part 1 of the Journal of the Royal Agricultural Society of England, 1895, the first English writer on agriculture, Fitzherbert, says, in his Boke of Husbandry, published by Pynson in 1523, when describing the "deseases and sorance of horses", that "Glaunders is a desease that may be mended, and cometh of a heate and a sodeyne colde, and appereth at his nosethrylles and betwene his chall (jowl or jaw) bones. Mournynge on the chyne is a desease incurable, and it appereth at his nosethryll lyke oke water. A Glaunder, when it breaketh, is lyke matter. Broken winded and pursiveness is but shorte blowynge. . . . The Farcyon is an yll soraunce and maie well be cured in the begynnynge and wyll appere in dyuerse places of his bodye, and there wyll ryse pymples as muche as halfe a walnut-shell, and they will followe a veyne and wyll breake by itself, and as many horses as do playe with him that is sore and gnappe of the matter that runneth out of the sore shall have the same sorance within a moneth after; and therefore keep the sycke from the whole. And if that sorance be not cured betyme he wyll dye of it."
Other writers - Dr. Bracken on the Art of Farriery, 1739; Mr. Gibson, 1751; James White, 1802 - give their views as to the nature and origin of the disease. Dr. Bracken does not believe that the affection is contagious any more than a cold or consumption is, in which he is probably correct, as both these diseases are undoubtedly contagious, but he guards his expression of opinion against any mistake by asserting that the cause of the disease is atmospheric. It is curious to note that the same authority considers the discharge from the ulcers of farcy may be contagious. Mr. Gibson looks upon glanders as the most infectious of all maladies that attack the horse. James White also considers glanders a contagious disease, but he believes also that it may arise spontaneously, adding, however, that the most common cause of farcy is contagion from a glandered or farcied horse. That he considered the diseases to be identical is apparent from his remark that they will reciprocally produce each other.
Not many years ago numerous causes were quoted as being directly or indirectly concerned in the production of glanders, as, for instance, the debility arising from attacks of acute diseases, insufficient or bad quality of diet, and generally exposure to insanitary conditions. Since the discovery, however, of the infecting organism of glanders by Schutz and Lofrler in 1882, which is known as the Bacillus mallei (fig. 213), only one cause can be referred to, i.e. the transmission of the infecting germ derived from a diseased animal. That the bacillus of glanders is the real cause of the disease was proved by Schutz, who cultivated the organism on boiled potato, also on the sterilized serum of the horse and sheep, and produced glanders in horses and other animals by inoculation with the pure cultures.
Fig. 213. - Bacillus mallei.
1. Trachea, showing earliest stage of glanderous ulceration. 2, Portion of Lung, showing superficial nodules of glanders. 3. Section of Lung, showing A, haemorrhagia or earliest perceptible stage of pulmonary glanders; B, extended haemorrhage; cc, commencing caseation; D, cavity filled with caseous matter; E, fibroid degeneration of nodule. 4 Ulcerated Mucous Membrane of Nasal Septum.