Known as Quarter Ill, or the Black Spauld of the English Shepherds, or as one of the “Murrains” of this country. It affects young and thrifty sheep, and is rarely found in old and poor stock. It is most common in wet seasons, in the early spring or summer and fall, and when the feed is very luxuriant. The sheep gorge themselves with the rich vegetation, and the digestion being over-taxed, the system is disorganized and the sheep suddenly droop and die. On examination, the wool leaves the skin at the slightest touch, and the body is found to be swollen and blackened in large patches, chiefly on the hind or fore quarter. Air is infiltrated under the skin, and the carcass seems already decomposed and full of black blood. On examining the flock, some will be lame or limping, the eyes red, and the mouth and tongue inflamed and blistered, and on passing the hand over the sides or quarters, they will be found swollen, the wool readily coming off, and a crepitation be heard from the confined air beneath. The urine is dark, the bowels constipated and dung bloody. After a time the animal is unable to stand, and falls upon the side; stretches out the limbs and in a few hours is dead.
The disease is worse on moist, rich bottom lands, and is rare on dry hills or gravelly soils. To prevent the disease, such soils and localities should be avoided, and the sudden changes from poor to such rich and succulent and abundant pasturage.
Treatment.—The disease is incurable, and diseased animals should be killed at once, the bodies burned and the premises disinfected as given under Abortion, page [122]. The healthy animals should be moved to another pasture and the infected pasture burned off the following winter, this destroys the germs in that pasture.
Cattle may be rendered immune to Black Leg by vaccination. The vaccine with directions for its use is given away to stock owners by the Chief of the Bureau of Animal Industry, U.S. Department of Agriculture, Washington, D. C.
Foot and Mouth Disease—Eczema Epizootica
Definition.—An acute, contagious fever, characterized by the formation of vesicles and ulcers, chiefly about the mouth and hoofs, etc. The eruptions appear on the mucous membrane of the mouth, on the fetlock, and in the cleft of the hoofs, and not unfrequently as a eruption on the udder. The disorder chiefly prevails among cattle and sheep, but under favoring circumstances, also attacks other domestic quadrupeds, and even man.
Causes.—It appears as an epidemic, and spreads exclusively by contagion. The precise nature of the germ is unknown, but it is chiefly limited to the contents of the vesicles, the secretion of the ulcers, the saliva, the blood and the natural secretions and excretions, of the diseased animal; and these convey the disease. The predisposing causes are exposure to cold, wet, currents of cold air, poor fodder, want of cleanliness and good housing; and anything that tends to lower the constitutional vitality. The activity of the virus is preserved for many months. The poison may be conveyed by the clothes of herdsmen and other persons, by manure, tools, fodder, by grass and ground previously trodden by diseased animals, and milk to suckling calves, indeed by almost anything. It finds its way into the system in various ways, not depending on any wound for admission. The communication to man is by drinking the milk of diseased cows. A second attack is rare.
Symptoms.—After a period of incubation, lasting from three to six days, the animal is seized with a shivering fit, and appears dull and stupified. A vesicular eruption soon appears on the mouth, the hoofs, and the teats. Suckling lambs, have a similar eruption on the mouth and throat, with irritation of the whole alimentary canal, attended with inability to suck, and exhausting diarrhea. The eyes are then observed to be dim, watery, congested; the muzzle, ears and horns alternately hot and cold; shivering ensues; rumination is diminished; the milk is less in quantity, yellower and thicker than usual, and much deteriorated in quality; the bag swollen, tender, hot; the back arched; the coat staring and harsh; the pulse somewhat accelerated; the temperature moderately elevated, reaching 102°, or even 104°; the eruption in the mouth is first seen on the inner surface of the upper lip, the edge of the upper jaw where there are no teeth, on the tip and edges of the tongue, and is indicated by salivation, by pain and loss of power in taking and eating food. The vesicles occur on the mucous membrane, singly or in patches, first as little red spots, then as whitish-yellow, slightly turbid blisters, about the size of a bean, at first transparent, but subsequently filled with a puriform fluid. These vesicles burst in about eighteen hours, discharge their fluid, leaving behind shallow ulcers, which often run together and then form deep and ragged ulcers. The lips, cheeks, tongue, and sometimes the Schneiderian membrane, are affected. The eruption on the feet is first seen around the coronet and in the interdigital space, especially of the hind legs; and the resulting vesicles burst quickly, because of the animal’s movements. The animal evidently suffers intense pain, is lame or unable to stand, and moves reluctantly or cautiously; the hoofs swell; the vascular secreting membranes become inflamed; the hoofs are cast; the bones may become diseased; and serious mischief may ensue. The eruption on the udder turns to vesicles, as in the mouth, and, when the fluid dries or escapes, thin scales are formed. The teats are swollen and sore. In exceptional cases, a vesicular eruption appears on the muzzle, the mucous membrane of the nostrils, the conjuctivae of the eyes, and the mucous membrane of the vagina.
In favorable cases, the fever subsides about the fourth day, the eruption declines, the appetite returns, and in seven to fourteen days the animal recovers. But complications are not uncommon. And in unfavorable cases the fever is high, the ulceration increases, the animal suffers from exhaustion, wasting, discharge of stringy, bloody mucous from the mouth, and of offensive matter from the nostrils; the face is swollen, the breath foul, the respiration rapid and grunting; the pulse small, weak, rapid; the blood becomes impure; the belly and legs œdematous; the hoofs slough off; diarrhea supervenes, and death follows about the ninth or tenth day.
Prognosis.—This is unfavorable—The United States Government and the Health Officers of the several States require all suspected cases of Foot and Mouth Disease to be quarantined, and upon the full development of the disease all animals infected to be killed. Human beings are liable to become infected, great care should be exercised in handling diseased animals or their carcases.