Part 95

In its very acute form many of the cases run their course in from five to eight days. In these the local lesions are not strongly marked, and death seems due to acute intoxication. In other enzootics the majority of the affected animals live from three to five weeks. These are cases that occasionally present the pulmonary and intestinal symptoms, and sometimes develop also caseo-necrotic lesions in the liver.

Ordinarily cases show no tendency to spontaneous cure. Left to themselves they die. On the contrary, if taken in hand early, the disease is readily amenable to treatment. In the latter event the prospects of recovery are excellent.

Differential diagnosis.--Necrotic stomatitis may be differentiated from foot-and-mouth disease by the fact that in the latter there is a rapid infection of the entire herd, including the adult cattle, as well as the infection of hogs and sheep. The characteristic lesion of foot-and-mouth disease is the appearance of vesicles containing a serous fluid upon the mucous membrane of the mouth and upon the udder, teats, and feet of the affected animals. In necrotic stomatitis vesicles are never formed, necrosis occurring from the beginning and followed by the formation of yellowish, cheesy patches, principally found in the mouth. Mycotic stomatitis occurs in only a few animals of the herd, chiefly the adult cattle, and the lesions produced consist of an inflammation of the mouth and lips and of the skin between the toes, followed in a few days by small irregular ulcers in the mouth. This disease appears sporadically, usually in the early fall after a dry summer, does not run a regular course, and can not be inoculated.

Prevention.--Prophylaxis should be carried out along three lines:

(1) Separation of the sick from the healthy animals.

(2) Close scrutiny and thorough disinfection once or twice daily for five days of the mouths and nasal passages of those animals that have been exposed.

(3) Complete disinfection of all stalls and sheds.

The disease appears to break out in winter and hold over to spring. It is conceivable that exposure to cold might so disturb the normal circulation of the oral tissues as to make the mucous membrane an excellent location for the causative factor of the disease. There is another possibility, however, which bears on the third line of prophylaxis. The so-called diphtheritic inflammations of the vagina and uterus in cows are caused by the same organism that induces necrotic stomatitis. A European writer has recently pointed out the almost constant relation of such attacks to previous occurrences of foul foot or foot rot in the same or other cattle on the place.

In all likelihood, in such cases, the stalls and sheds are the harborers of this germ. It is possible that many of these outbreaks have some relation to preceding cases of the above-mentioned diseases and the greater use in winter of the stalls and sheds, thus harboring the Bacillus necrophorus.

Treatment.--The treatment consists almost solely in careful and extensive cleansing and disinfection of the mouth and other affected surfaces. The mucous membrane of the mouth should be copiously irrigated with a 4 per cent solution of boracic acid in warm water at least twice daily. As exposure to oxygen kills the bacilli, one need have no fear about disturbing or tearing off the caseous patches or necrotic tissue during irrigation. The irrigation of the sores should then be followed by the application with a brush or rag on a stick of a paste made with 1 part of salicylic acid and 10 parts of water, or the affected areas may be painted with Lugol's solution of iodin (iodin, 1; potassium iodid, 5; water, 200). Frequent injections of 1 per cent carbolic-acid solution into the mouth make an excellent treatment. The internal administration of 2 grams of salicylic acid and 3 grams of chlorate of potassium three times a day has also proved to be very beneficial when accompanied with local antiseptic treatment.

MALIGNANT CATARRH.

Malignant catarrh, or infectious catarrhal fever, is an acute infectious disease of cattle preeminently involving the respiratory and digestive tracts, although the sinuses of the head, the eyes, and the urinary and sexual organs are very frequently affected. It is relatively rare in this country, being more common on the continent of Europe. Outbreaks have occurred, however, in Minnesota, New York, and New Jersey. So far the causal agent of the disease has never been isolated, and inoculation experiments with the view of artificially reproducing the disease have proved negative in every case. In spite of the foregoing statements the consensus of opinion of eminent investigators points to malignant catarrh as being of specific origin; that is, due to some form of microorganism the contagious character of which is poorly developed. This accounts for the slow transmissibility of the disease from one animal to another. In fact, malignant catarrh is a type of that class of affections scientifically known as miasmatic diseases; that is, they remain stationary in stables with damp floors, low ceilings, poor ventilation, and bad sanitary conditions in general. Such places furnish a favorable seat of propagation for the infective material, and it will remain active for a long time, causing the loss of a few animals each year. One European veterinarian reports an instance in which the disease remained for 25 years on the same farm, attacking in all 225 animals, with a mortality of about 98 per cent.

The disease is most common in late winter and early spring, at all altitudes, and has a special preference for young, well-nourished cattle, although older animals are not immune. The time between the entrance of the infective principle into the body of the animal and the appearance of the first symptoms is relatively very long, averaging, according to German investigators, from 20 to 30 days. Fortunately, it is not a disease which spreads to any great extent or which causes severe losses, and hence legislative enactments do not seem to be necessary for its restriction.

Symptoms.--These are extremely variable according to the point of localization of the lesions. It is usually ushered in with a chill, followed by a marked rise of temperature (104∞ to 107∞ F.). The head droops, the skin is hot and dry, and the coat staring. Quivering of the muscles in various parts of the body is frequently observed. Marked dullness of the animal, passing, according to some observers, into an almost stupefied condition later on, is quite common. The secretion of milk stops in the beginning of the disease, and loss of flesh, invariably associated with the disease, is extremely marked and rapid. The lesions of the eyes may best be likened to moon blindness (periodic ophthalmia) in horses.

There is first an abundant secretion of tears, which run down the face. The lids are swollen and inflamed, and indeed this may be so marked as to cause involuntary eversion, exposing the reddened conjunctiva to view. Sunlight is painful, as is shown by the fact that the animal keeps the eyes continuously closed. This inflammation may extend to the cornea, causing it to assume a slightly clouded appearance in mild cases or a chalky whiteness in more severe affection. Cases of ulceration of the cornea followed by perforation and subsequent escape of the aqueous humor, leading to shrinking of the eyeball and permanent loss of sight, have been recorded, but these are relatively rare, although slight inflammation of the deeper structures of the eye (iris) are more frequent. In mild cases this inflammation may undergo complete resolution, but more frequently permanent cloudliness of the cornea, either diffuse or in spots (leucoma), is the result. The mucous membrane of the mouth, nose, sinuses of the head, throat, and lower respiratory passages are also involved. It is first catarrhal in character, but soon a false or diphtheritic membrane is formed, with the production of shallow ulcers. There is dribbling of saliva from the mouth and discharge from the nose, at first watery, becoming thicker and mixed with blood and small masses of cast-off croupous membrane, causing a very fetid odor. These croupous areas when they form in the throat, larynx, or windpipe, may lead to narrowing of the passages, with consequent difficult breathing and even suffocation. Various respiratory murmurs may also be heard, caused by the to-and-fro movement of mucus and inflammatory deposits along the air passages. There is also inflammation of the horn core with consequent loosening of the horn shell, and the horns are thus readily knocked off by the uneasy, blind sufferer. The animal may refuse all feed from the time of the initial rise of temperature, or in less severe cases, and especially when the lesions of the digestive tract are not so marked, the appetite may remain until the disease is well advanced. Constipation is quite common at the commencement of the attack, followed by diarrhea and severe straining, the evacuations becoming very soft, fetid, and streaked with blood. Cases of the evacuation of desquamated patches of diphtheritic membrane from the intestinal mucosa 6 to 9 feet in length have been reported. The kidneys and bladder are usually inflamed, the urine being voided with difficulty and the animal evincing signs of pain. Inflammatory elements, as albumen, casts, etc., may be seen on examination of the urine. In cows the mucous membrane of the vestibule is congested, swollen, and may contain ulcers and an excessive quantity of mucus. Abortion during advanced pregnancy is not infrequent, following a severe attack. In connection with these various symptoms there may be much uneasiness on the part of the animal, leading in some cases to madness and furious delirium, in others to spasms and convulsions or paralysis. A vesicular eruption of the skin may occur, seen principally between the toes and on the inside of the flank and in the armpits, with subsequent loss of hair and epidermis.

Like other infectious diseases, malignant catarrh pursues a longer or shorter course in accordance with the severity of the attack. In acute cases death is said to take place three to seven days after the appearance of symptoms. Recovery, if it occurs, may take three or four weeks. According to statistics, from 50 to 90 per cent of the affected animals die.

If animals which have died of this disease are examined, in addition to the changes of the mucous membrane of mouth and nasal cavities referred to above, shallow ulcers in these situations will be found occasionally. These necrotic processes may pass beneath the mucous membrane and even involve the underlying bony structure. In severe cases membranous (croupous) deposits are found in the throat. Similar deposits have been found upon the mucous membrane of the fourth stomach and intestine, which is always inflamed. There is more or less inflammation of the membranes of the brain, kidneys, and liver, and some fatty degeneration of the voluntary muscles. In countries where rinderpest occasionally appears it may be difficult to distinguish between it and malignant catarrh, owing to a general similarity of the symptoms. The principal points to be observed in differentiating between the two are the very slight transmissibility of the latter as compared with the intense contagiousness of the former, and the tendency of malignant catarrh to run a more chronic course than rinderpest, which usually results fatally in a very few days. Only a trained veterinarian who takes into consideration all the different symptoms and lesions of both diseases should decide in such cases.

Treatment.--There is no specific treatment for this affection. Copious blood letting in the earliest stages has been highly recommended, however, as this has a tendency to deplete the system and lessen the exudation of inflammatory products. Antiseptic washes, such as 4 per cent boric-acid solution to the eyes and Dobell's solution applied to the nose and mouth with ice poultices over the crest of the head and frontal region, have also proved efficacious. Calomel should also be given in 1-dram doses twice a day for three days, and in severe cases, involving the respiratory tract, a powder containing ferrous sulphate, quinin, and subnitrate of bismuth, given twice a day, will be found beneficial. At the same time it must be remembered that much greater success is to be looked for in the preventive treatment. This consists in the removal of the healthy from the infected animals (not vice versa) and thorough cleaning and disinfecting of the contaminated stables. If the floors are low and damp, they should be raised and made dry. If this can not be done, place a layer of cement under the stable floor to prevent water from entering from below. The stable should be well ventilated and the soil in the pastures thoroughly drained. If this is carefully carried out, the contagion should be destroyed and the danger of the reappearance of the disease in a great measure lessened.

MALIGNANT EDEMA.

Malignant edema, also termed gangrenous septicemia, is an acute, inflammatory disease of domestic and wild animals, resulting from the introduction of a specific organism into the deep connective tissues of a susceptible animal and proving fatal in many instances within 24 to 48 hours. The disease may be inoculated from one animal to another, but only by inserting the virus deeply below the skin. It is infrequently met with in cattle, but may follow operating wounds, as roweling, castration, and phlebotomy, which have become infected with septic matter, soil, or unclean instruments. In the pathological laboratory of the Bureau of Animal Industry the organism has also been obtained from the infected muscles of a calf that was supposed to have died of blackleg, and, as a result, all blackleg virus is thoroughly tested before it is made into blackleg vaccine in order to exclude the malignant-edema organism. The essential cause of malignant edema is a long, slender, motile, spore-bearing bacillus, resembling the bacillus of blackleg, and which can develop only in the absence of the atmosphere. Unlike the bacilli of anthrax and blackleg, which are confined to certain districts, this organism is widely distributed and found in ordinary garden soil, foul water, and in the normal intestinal tract of the herbivora. It may be brought to the surface of the soil by growing plants, rains, winds, or burrowing insects and rodents. In animals that have succumbed to the disease the germ is confined to the seat of infection, but a few hours after death it may migrate through the blood channels to other parts of the body. The bacillus may attack man, horses, asses, goats, sheep, pigs, cats, dogs, and poultry. Adult cattle, although refractory to experimental inoculation, suffer from natural infection, while calves are susceptible to both these methods of exposure. (Kitt.) The introduction of the bacillus into abrasions of the skin and superficial sores rarely does any harm, because the germ is quickly destroyed by contact with air. If, however, the organisms are inserted deeply into the subcutaneous tissues of susceptible animals, they quickly develop, producing a soluble poison, which is the fatal agent.

In lamb-shearing season, or after docking or castration, the mortality is higher among these animals because of wounds inflicted at such times. The application of antiseptics to wounds thus made will reduce the percentage of deaths to a minimum.

Symptoms.--Usually the first symptoms are overlooked. In the early stages the animal appears listless, disinclined to move about, and lies down in shady and quiet places. If forced to move about, the hind legs are drawn forward with a peculiar, stiff, dragging movement, and there may be slight muscular trembling over all the body, which becomes more intense as the disease progresses. When driven, the animal shows signs of fatigue, ultimately dropping to the ground completely exhausted. Breathing becomes fast and painful, with frequent spasmodic jerks.

The pulse is quick and weak and the temperature is 106∞ to 107∞ F. An edematous, doughy, and painful swelling appears at the point of infection. This tumefaction spreads more and more, and crackles on pressure. In case of an open wound, a fetid liquid and frothy discharge is observed. The center of the swelling may appear soft and jellylike, while the margin is tense, hot, and painful. The symptoms increase rapidly, resulting in coma and death.

Lesions.--After death the fat and subcutaneous tissues surrounding the infected area are infiltrated with a yellow gelatinous material containing an orange-colored foam, due to the presence of gas bubbles.

The muscles at this point are friable, spongy, and of a uniform brownish tint, dissociated by gas and with a blood-tinged exudate. This gangrenous tissue, when present before death, can be removed without pain to the animal. The intestines are generally normal, but, together with the peritoneum, they may be inflamed, and the lungs are usually the seat of an edema. The spleen, liver, and kidneys retain their normal appearance, in marked contrast with anthrax.

Differential diagnosis.--Unlike blackleg, this disease never appears as an epizootic but in isolated cases. It may also be differentiated from the former by the history of a recent parturition or surgical operation, by the presence of an external injury at the site of the swelling accompanied with a fetid liquid discharge, and the gangrenous appearance of the tumefaction. Man is susceptible to malignant edema, but not to blackleg. Malignant edema may also be easily differentiated from anthrax in that the blood and spleen are normal in appearance, while in the latter disease the blood is dark and of a tarlike consistency, and the spleen appears swollen, injected, and softened. The local tumor in malignant edema contains gas bubbles, which are absent in anthrax swellings. Inoculation experiments of guinea pigs, rabbits, and chickens will also disclose the differences among the above-mentioned three diseases, since all these species are killed by the germ of malignant edema, only the first two species by the anthrax bacillus, while the guinea pig alone will succumb to the blackleg infection.

Treatment.--Treatment is chiefly surgical and consists in laying the infected areas wide open by free incision, followed by a liberal application of a 30 per cent solution of hydrogen dioxid and subsequently a 5 per cent solution of carbolic acid. Usually the disease when observed has advanced to such an extent that medicinal interference is without avail. Preventive treatment is by far the most desirable, and consists, essentially, in a thorough disinfection of all accidental and surgical wounds, the cleansing of the skin, and the exclusion of soil, filth, and bacteria during surgical operations of any nature. Sheds, barns, and stables should receive a thorough application of quicklime or crude carbolic acid wash after all rubbish has been removed and burned. All dead animals should be burned or deeply buried and covered well with quicklime.

SOUTHERN CATTLE FEVER (TEXAS FEVER, TICK FEVER).