Diseases of Domesticated Animals

DISEASES OF DOMESTICATED ANIMALS Reference is made here only to some of the more important disorders other than those described in separate articles which treat of ACTINOMYCOSIS, ANTHRAX, ABORTION, CANINE DIS TEMPER, FOOT-AND-MOUTH DISEASE, GLANDERS, PLEURO-PNEU MONIA, HYDROPHOBIA, RINDERPEST, SWINE FEVER. In treatment of animal patients the main object is to place them in those con ditions which allow nature to operate most freely in restoring health. Fresh air, cleanliness, quiet and comfort, should be se cured as far as possible.

The

Horse.—Epizootic Lymphangitis is a chronic contagious disease, characterized by inflammation of the superficial lymphatic vessels and regional lymphatic glands. Nodular swellings appear which soften and discharge a creamy pus, with formation of ulcers. The eruptions usually appear on the limbs but may occur elsewhere, and are caused by the cryptococcus of Rivolta. Inocu lation probably occurs through a wound, and lesions slowly ap pear. Affected animals are destroyed; they do not react to mallein, and the disease is thus distinguished from glanders.

Strangles is an acute contagious disease in which there is in flammation of the mucous membrane of the upper air passages and suppuration of lymphatic glands, usually the submaxillary, but other glands may be involved. An organism, streptococcus equi, is always present in the nasal discharge and in the abscess cavities, and is the probable cause, but a filterable virus has been suggested as the primary causative factor. Formerly common amongst young horses, it is becoming a rare disease under modern conditions. There is fever, catarrh, diminished appetite, languor and sore-throat ; the suppurating glands become swollen and pain ful, and then soften and discharge pus. Recovery usually follows and immunity is acquired. Irregular or atypical forms of the disease occur, and are more dangerous. Infection takes place by inhalation and ingestion and also by inoculation or wound in fection, with involvement of the associated lymph glands so that any part of the body may be affected. Widespread abscess

formation is sometimes seen, due to pyaemic infection of the blood stream.

Horse-pox (variola equina), a rare and benign disease, spreads like cowpox, by contact, and may be transmitted to man. Lesions appear on the skin, in the hollows of the heels, on the back of the limbs, and on mucous membranes, mouth, nose, etc. Isolation, with strict cleanliness, for three weeks is advisable.

Cattle.

Black-quarter or Blackleg is a specific infection of young cattle, the causal organism being B. chauveii. Large crepi tant swellings develop in the quarter or other parts ; there is high fever, with lameness, and later, marked depression, and death occurs within two days. Immunity can, however, be conferred by vaccination with blackleg aggressin, and the disease can thus be controlled.

Mammitis, or Garget, of which there are acute and chronic forms, is due to a streptococcus transmitted usually in the process of milking. In acute cases the udder becomes swollen, hot and painful ; in others the course is gradual, with little constitutional disturbance, the incubation period lasting for months. The milk may be scarcely altered or greatly changed and offensive. Tuber culous mastitis is of great importance and is usually chronic. Prevention depends on immediate isolation of affected animals, careful inspection, and cleanliness in housing and milking.

Milk Fever.—An intoxication associated with lactation most frequently met with in recently calved high-grade cows, but the goat, sow, bitch, mare and ewe are also susceptible. Symptoms vary widely, but usually involve the nervous system, causing excitement, spasms, paralysis, coma, and there is often marked disturbance of respiration, circulation and digestion. By inflation of the udder with filtered air or oxygen, as introduced by Schmidt of Kolding, Denmark, the mortality in this once fatal disease has been brought very low. Goats, ewes and mares respond to this treatment equally well.