HOG CHOLERA. A virulent contagious dis ease of hogs, due to the presence of a pathogenic bacillus in tine alimentary tract. The term has been used to cover at least two diseases, true hog cholera and swine plague (q.v.). Some authors have attempted to distinguish four or five dis eases of the hog-cholera group, hut the present tendency is to recognize only two.
The chief symptoms of hog cholera are a rise in body temperature, loss of appetite, a discharge from the eyes, watery at first hut later yellow ish and viseid, a purplish coloration of the skin, giving rise to a common name, blue sickness. oc curring especially on the ears, chest, and abdo men, the under side of the neck, and on the inside of the thighs. Constipation is an early symptom. but diarrhea soon sets in and persists until the death of the animal. The excrement is dark-col ored. and possesses a fetid odor. The body tem perature may rise from one to three degrees above the normal, but the elevation of temperature is frequently absent. The animals are dull and indifferent to surroundings, lie down a great part of the time and hide their heads under straw or litter, often have a dry cough, and sometimes squeal from intestinal pain. As the disease pro gresses they become gaunt with arching hacks. The mortality from hog cholera under ordinary conditions is from SO to 90 per cent. Acute cases may last from two to live days; chronic one:, a month. Clic characteristic pathological changes are enlargement of the spleen and a hemorrhagic condition of the large intestines and lymphatic glands. In chronic cases, ulcers are formed in the large intestines or the whole wall may become effused with blood.
Hog cholera and swine plague have been fre quently confounded. but in typical cases they may be distinguished by clinical symptoms and 1,0st•tnurtem lesion:. 111 most outbreaks of con hog disease:, cholera and swine plague occur in combination in the same animal. In general, however, the seat of infection in hog cholera is in the intestines; that of swing plague is in the lungs and secondarily in the intestines.
A reddening of the skin is an indication of hog cholera, while coughing is more pronounced in eases of swine plague. For a reliable differential diagnosis of the two diseases it is necessary to make pure cultures of the micro-organisms which are concerned.
No satisfactory medicinal treatment has been devised tor hog cholera. Recognized tonic: which assist in keeping hogs in good physical condition may render them less susceptible to disease. A mixture containing sodium salts, sulphur, sul phide of antimony, and charcoal has proved as effeetive as any remedy. Ser11111 therapy for hog cholera is still in the experimental stage, but has given promising results. The serum treatments devised by Pasteur and Lorenz have proved satis factory in Europe. Experiments in the United States have demonstrated that, serum used alone confers only a partial and temporary immunity to hog cholera. On the other hand, when anti lox ic serum was used in combination with a viru lent culture of the hog-eholera bacillus in the proportion of ten to one, a complete and lasting immunity was produced in more than 50 per cent. of eases.
It has been found practically impossible to dis infect hog pens and yards after an outbreak of hog cholera. Infected pen: should be burned, and the surrounding ground should be cultivated to some crop for at least a year before again using as a hog.yartl. Pens should be kept as clean as possible, and treated from time to time with lime or whitewash. By ohserying these precautions, preventing infection of the water supply, and quarantining imported hogs before allowing them to run with the herd, the liability to infection from hog, cholera will he much re duced. Consult: Soeard and Led:Linda., Les ?maladies mirrobiennes des (minions ( Paris, ISOS) : de Schweinitz, "Hog Cholera," and "Swine Plague." in United States Department of Agriculture. Bureau, of Animal Industry Reports (Wa:hiTdon, 1589-92).