Rouget in Europe and Hog Cholera and Swine Plague, as the best established types in the United States deserve primary mention, to be followed by references to additional types which have been found to be associated with other distinct microörganisms.
ROUGET, ROTHLAUF. RED FEVER OF SWINE. SWINE ERYSIPELAS.
Definition. Comparative immunity of sucking pigs. Disease unknown in America. Causes: Bacillus erysipelatos suis, mature age, infection through yards, buildings, troughs, dust, mice, rabbits, pigeons, men, dogs, vermin, birds, butcher’s and kitchen scraps, swill, hot weather, damp seasons, close pens, movement of swine, stockyards, fairs, public conveyances, public highways. Symptoms: incubation three days, chill, violet mucosæ, hyperthermia, recumbency under litter, muscular weakness especially behind, inappetence, thirst, costiveness, later diarrhœa, tenderness to touch, lymph glands swollen, red, blue, violet or black discoloration of skin, cutaneous swelling and pitting. Course: death in 12 hours to 6 days, or convalescence prompt. Mortality 20 to 80 per cent. Lesions: congestion of capillary vessel, blood extravasations, petechiæ, affecting cutis and subcutaneous fat, lymph glands congested, discolored; lungs engorged; spleen enlarged, liver and kidneys congested, petechiæ general, blood little altered. Bacillus 1.5 μ, anærobic, easily destroyed in pens, in pork. Pathogenesis: swine, rabbits, mice, rats, pigeons and sparrows suffer. Rabbit germ less fatal to pigs. Immunization, advantages and drawbacks. Technique.
Definition. A microbian disease of swine manifested by high fever, great prostration and muscular weakness, a violet tint of the visible mucosæ, red or violet discoloration of the skin in spots and patches or universally, enlarged lymph glands, encreased size of the spleen, and general congestion of the capillary plexus.
Contrary to the habit of hog cholera and swine plague, rouget attacks mature swine mainly, the sucking pig showing a remarkable power of resistance. It does not appear whether this is due to the animal (milk) diet or to the absence of infection from feeding in the trough used by the adult animals. Up to the present this disease has not been recognized in America.
Causes. The one essential cause of rouget is the presence of the bacillus. The other conditions are either such as predispose the animal to receive it, for example, mature age: or they are such as favor diffusion of the poison, such as the introduction of an infected animal, the feeding of the healthy from the same manger with the infected, the introduction into the manger of the feet or snout which have become soiled with the infected manure or urine, the distribution of the infection in dust, the introduction of the bacillus in the bodies of mice, rabbits, or pigeons, or on the feet of those animals, of men, dogs, birds, and vermin. We may add the distribution of infection in dried butcher’s scraps used in pig feeding, and in uncooked scraps from the kitchen or in hotel swill.
It has been noted that the highest mortality prevails in hot summer weather, in damp seasons, and in narrow, confined, badly ventilated pens. Under such circumstances the introduction of a diseased pig will lead to the infection of most of the others in a few hours. Infection is quite as prompt through public pens in stock yards and fairs, and in public conveyances (cars, stock wagons, steamboats, ferry boats, etc.) and public highways.
Symptoms. After a period of incubation of three days or more the subject is seized with shivering, the limbs are hot and cold alternately, respiration and heart beats are accelerated, the mucous membranes assume a dark violet tint and the rectal temperature rises to 104° to 108° F. From the first the pig tends to bury itself under the litter, and refuses to move unless absolutely forced to do so, and then only with painful grunts, swaying and staggering limbs (especially the hind ones), and straight drooping tail. There is inappetence, but thirst remains, and the bowels are at first costive, the manure being covered with a film of mucous or even streaks of blood; later they become relaxed and diarrhœa becomes often a prominent symptom. The pig seems to suffer and often squeals when handled, and he may give a weak, dry cough. The external inguinal glands may often be felt perceptibly enlarged. The red discoloration of the skin appears early and extends and deepens to the end in fatal cases. It may be of a bright red, or of a bluish red, violet or black. The first indications appear as spots, by preference around the roots of the ears, on the breast and abdomen, inside the arms and thighs, and in the perineum. These isolated spots run together into great patches, which extend over the whole ventral aspect of the body, and may cover the entire dorsal aspect as well. In some instances the skin is swollen and retains an impression made by the finger.
Course. The disease may reach a fatal termination in twelve hours: more commonly it endures for forty-eight hours, and at times it will last for four, five or six days. In the most rapidly fatal cases, the violet discoloration of the skin may be absent or only a little marked, while in the protracted cases it acquires its greatest extensions and its darkest shades. In the protracted cases too the prostration becomes extreme, the animal may find it impossible to raise himself on his hind limbs, the diarrhœa becomes profuse, liquid and fœtid, the respiration labored, cyanosis sets in and the temperature is reduced below the normal standard.
In case of recovery, convalescence is usually prompt and complete, differing in this from cases of swine plague and hog cholera. The more favorable issue in rouget probably depends on the comparative integrity of the intestinal mucosa and mesenteric glands, which are subject to slow healing lesions in swine plague and hog cholera. Slow convalescence is however not uncommon, yet in such cases, the concurrent, speedy and complete recoveries in other animals in the same herd serve to identify the disease as rouget.