Text book of veterinary medicine, Volume 4 (of 5)

by James Law

Causes. The disease, as hitherto observed, has been invariably associated with microbian infection of the genito-urinary mucosa, but no one microörganism has been found to be constantly present. In the 1888 cases, Nocard isolated from the kidneys and lumbar cord a small, motile bacillus which was not stained by Gram’s method and the inoculation of which proved fruitless. Zschokke, in 1889, found in the kidneys, lungs, liver and spleen of both horses and cattle, the victims of a progressive infectious paralysis, a bacterium coli commune 1.5μ long by 0.7μ broad, which stained in methylin blue and grew in agar and gelatine, and when inoculated under the skin of a goat provoked paralysis. It had no effect on a pig. In keeping with this, Thomassen, in 1893, alleged that the bacillus coli communis in certain conditions, when colonized in the solid organs, produced a toxin which caused paresis and paraplegia. Blin and Lambert, in 1896, found in the urine, in pure cultures, a short ovoid microbe, motile, non-liquefying and bleached by Gram’s solution. It grew on gelose and peptonized gelatine as a creamy surface layer which did not extend into the medium, and assumed a brownish color as it became older. On potato it formed a superficial bright yellow film. In bouillon the surface film which formed gradually precipitated to the bottom of the vessel.

This microörganism was not found in the blood, liver, muscles nor spinal cord.

Inoculation into the pleural cavity of the horse induced pleuro-pneumonia.

The contagion appears to be transmitted through the urine and morbid discharges of the urino-genital canal, falling on the litter and floor and thus contaminating the tail, and indirectly the generative organs. The brushes, combs and rubbers used on one horse after another are similarly incriminated. The mares, having a wider exposure to infection, appear to suffer most. Comeny saw eighty sick mares to twenty-eight horses, and the mortality was thirty-four mares to three horses. The smallness and length of the male urethra and its frequent flushing throughout its whole length with urine seems to give a greater measure of immunity to the horse.

In the Blin and Lambert cases the indications pointed to a local infection and to the presence in the spinal cord of the toxins alone. It may be assumed that in such cases there was a purely local infection. In the Zschokke cases on the other hand, with microbian infection of internal parenchymatous organs the presumption is that the paralysis was due to a totally different infection, as appears to be further indicated by the morphology of the microbe. They may have been, however, but the advanced and generalized stages of a primary local infection.

Lesions. These appear to vary with the progressive advance of the malady. In an ass which was killed as soon as paraplegia appeared and the necropsy made at once, the lesions were confined to the vulva, vagina and bladder. In advanced cases the ureters and kidneys are visibly involved together with the spinal cord, especially in the lumbar region, and in certain instances the brain.

The vulva is swollen, held habitually open so as to expose the erect clitoris; the mucosa is irregularly swollen and petechiated, and there is a glairy or bloody discharge. The swelling usually extends to the inner side of the thighs, the mammary glands and the adjacent wall of the abdomen. The vaginal mucosa is congested, swollen so as to bulge irregularly at intervals and covered with a glairy muco-purulent matter often mingled with clots of blood. The urethra and bladder are red and congested, with marked thickening and ecchymosis of the mucosa and an abundant serous exudate which extends into the muscular and peritoneal coats as well. Minute extravasations are found in the two outer coats and petechiæ of the serosa is the rule. In fatal cases the ureters and kidneys are involved, the renal parenchyma is greatly congested and softened, the cortical part especially being of a dark red, and the glomeruli distinctly enlarged. An oily sanguineous liquid can be squeezed from the cut surface. The lumbar portion of the spinal cord together with its meninges, is congested and arborescent, and in bad cases this may extend upward to the head and involve the brain and its coverings.

There is general congestion of the venous system with black blood, especially noticeable in the arborescent lines on the inner surface of the skin and in the serosæ, and the liver and spleen are gorged with black blood, which, however, reddens on exposure to the air. Muscles and parenchymatous organs may show a parboiled appearance. In the male the swelling appears about the sheath and penis, the papilla, the urethral mucosa and that of the bladder are deeply congested and petechiated, and the kidneys and medulla may be implicated as in the mare.

Symptoms. In the mare the early symptoms are the swelling and gaping of the vulva, with the muco-purulent or sanguineous discharge and the presence of redness, congestion and petechiæ of the mucous membrane.

In the horse there is swelling of the sheath and a pendant condition of the penis, which in its turn may be irregularly reddened and swollen, and the papilla and orifice of the urethra are deep red and angry.