Part 96

The abomasum is profoundly involved, especially in the vicinity of the pylorus. The folds are of a deep blood red or purple, or blackish, port wine hue, or they may be in part brownish red, or when necrotic, slate colored or mottled. The peptic glands are swollen, elevated and dilated, and patches and spots of softened and loosened epithelium are easily detached leaving a deep red surface with, it may be redder oozing points. Ulcerous sores may show on the summits of the folds. The contents are a viscous, fœtid grayish yellow, or reddish liquid, without solid ingesta.

The small intestines show similar lesions, deep, dark red congestions, most intense on the summits of the folds, softened, loosened, ragged patches of epithelium, erosions, ulcers, circumscribed sloughs, casts of the gut formed by desquamating epithelium, and congested, enlarged, and prominent aguimated and solitary glands are more or less in evidence. The contents are liquid and yellowish, grayish or reddish and fœtid. Microscopically the distension of the glands, (of duodenum, Lieberkuhn and Peyer), the proliferation and softening of the epithelium, the enlargement of the nuclei of these and of the cells of the submucosa, and the profusion of microörganisms are marked features.

In the cæcum and colon the lesions are usually less prominent, though swelling, softening and desquamation of the epithelium often exists, and points and patches of congestion, ecchymosis, and necrosis are not uncommon, particularly in the cæcum, and may extend to the muscular layer.

The terminal portion of the rectum is especially liable to marked congestion and blood extravasation, with more or less desquamation and erosion. The summits of the mucous folds are often of a dark red (port wine) hue, and as this is everted and exposed in defecation or later by the relaxation of the sphincter it becomes a marked lesion even in life.

The spleen is normal in strong contrast with anthrax in which similar gross lesions are often found on the mucosæ and especially the rectum.

The liver is usually rather pale and soft, as in other cases of high fever and centres of necrosis may be present. The gall bladder contains a variable amount of thin bile. The pancreas is nearly or quite normal. The lymph glands generally and especially those of the mesentery and abomasum are congested, enlarged and softened.

The kidneys are congested, often petechiated, swollen and softened, with centres of necrosis. The bladder, vagina and uterus show mucous congestion, and thickening uniformly or in spots with muco-purulent secretion.

The lungs show spots of hyperæmia, extravasation and at times hepatization, but a very characteristic lesion is the interlobular emphysema already referred to as connected with the abdominal pain and the sudden arrest of inspiration. This gives a gross appearance of marbling as in lung plague, only in this case the inflated interlobular tissue is dark colored instead of white as in lung plague, and it collapses at once when incised.

The encephalon, medulla and nerves present more or less hyperæmia and even exudation.

The heart is usually pale except in the spots infiltrated by blood, but it may be mottled with petechiæ and particularly on the endocardium. The pericardial fluid is often red. The blood is at first little altered, but later undergoes marked changes, notably an increase of fibrine (50 per cent.) and a decrease of water (as in Asiatic cholera). There is marked leucocytosis, and distortion of the red globules. Before death it becomes black and incoagulable.

The whole capillary system tends to be relaxed and over-distended (congested).

Incubation. As seen in England the incubation was from four to five days. Four to nine days are claimed by Galtier as the extremes, yet he quotes incubations apparently as short as 12, 24, 36 and 48 hours respectively. A source of fallacy rests in the prevalence of cattle plague in the district and the possibility of infection through unsuspected channels, before the recognized exposure. Something must also be allowed for the greater susceptibility and the larger dose of the poison which would tend to shorten the incubation. Thus the western improved breeds, which suffer a mortality of 80 to 95 per cent. (Refik Bey), and the winter season, when the virus is concentrated in small ill ventilated houses, both tend to shorten the incubation. At the Albert Veterinary College in 1865, Gerlach went direct from the infected stable to the sound one, and in 48 hours several of the cattle in the latter had a manifest rise of temperature. Roloff observed the elevation of temperature in 36 hours after exposure, and Ranpach and Ravitsch as early as 11 hours after the inoculation.

Symptoms. The earliest symptom is abrupt hyperthermia, (104° to 108° F.). This is virtually pathognomonic in a herd or locality in which the disease exists, or in suspected animals presumably coming from an infected region. The temperature usually rises to its height on the third or fourth day, and falls materially when other symptoms are developed. In some instances death supervenes during the high temperature, but in the majority the temperature goes below the normal before death.

Often on the second day, or the third, white epithelial eruptions or concretions appear on the inner sides of the lips, closely resembling the eruption of muguet (thrush) and often showing also on the dental pad of the upper jaw and along the gums of the lower. In connection with the high temperature, which is absent in thrush, this symptom is virtually pathognomic. These concretions are more or less abundant in different cases, sometimes so slight as to be easily overlooked, and in other cases encreasing up to the sixth day, and covering not only the lips, dental pad and gums, but extending back over the hard palate, pharynx and gullet. The concretion is as soft as cream cheese, easily detached and leaves a bright red abrasion (not ulcerated) when removed.

By the fourth day there are dry or staring coat, sometimes rigors, sometimes small, accelerated pulse (60 to 120 per minute), some loss of appetite and impairment of rumination, dry muzzle, a general flush of the mucosæ (mouth, vagina, rectum), and deep blood red discoloration of many of the buccal papillæ. There is weariness or debility, the animal remaining down much of the time, also marked thirst, constipation, the fæces covered with mucus or blood, rapidly advancing emaciation, and marked tenderness of the skin, especially of the loins. The head and ears are drooped, saliva drivels, the mouth has a fœtid odor, the eyes weep, and there may be grinding of the teeth. The skin may be hot and the white and delicate parts (udder, teats) suffused by a deep blush. The milk is decreased at first and finally completely dried up.

As the malady advances the belly becomes tender, the constipation is succeeded by diarrhœa with much attendant rumbling, the fæces are at first watery, greenish and acid, and later highly offensive, yellowish brown or gray, and alkaline. These become encreasingly profuse, fœtid and liquid, assuming perhaps a pea soup or rice water consistency before death. The sphincter, at first firm and quickly responsive, finally undergoes permanent relaxation, with constant exposure of the dark red mucosa.

When the disease is fully established the respirations often become highly characteristic. There is not the sudden catching and shortening of the inspiration as in pleurisy, but a sudden closure of the glottis with an audible clicking sound in the course of the expiration, and, after a perceptible interval of holding of the breath, the expiration is resumed with or without an accompanying moan. This phenomenon is so characteristic as to be largely diagnostic. Whether it is due to abdominal pain roused by the sudden forward movement of the diaphragm, or to nervous disorder alone, it is a valuable symptom always to be looked for. It further explains the interlobular emphysema usually met with in the lungs in this disease.

In the more violent cases death supervenes from the sixth to the ninth day, but in the indigenous breeds of Eastern Europe and Asia, which represent a survival of the fittest, the great majority suffer mild attacks and recover, and even in newly invaded countries, when the invasion has spent itself and the less susceptible are largely attacked, a fair proportion survive for a longer period and even recover.

In these milder, protracted, or surviving cases the skin symptoms are likely to come out prominently. Chief among these and very constant at the height of the disease is an abundant unctuous exudation which dries on, forming a crust, comparable to what is seen on the skin in the fevers of swine. At different points, notably on the teats, udder, inner sides of the thighs, and arms, and on the neck, lips and face generally, are epidermic concretions having a warty-like appearance, and respectively seated on a very slightly swollen and congested point of the dermis. The deeper layers of these epidermic concretions often soften, so that they have been mistaken for vesicles and pustules, and hence the error by which cattle plague was held to be but a malignant form of cowpox. But these concretions are histologically distinct from vesicles; there is no liquid exudate on the papillary layer raising the epidermis in the form of a little sac, but merely an excessive production of the cuticular cells with abnormally large nuclei, as happens generally to cells in active proliferation, and an admixture with those of spores and mycelium of fungi which have no special significance.

Papules, vesicles and pustules may form on the diseased skin and are described by different authors, but they are not characteristic of the disease as are the epidermic proliferations.

In some rare cases nervous symptoms appear, the animal moves unsteadily without proper sense of balance, it may toss its head and horns as if attacking an enemy or it may sink into a somnolent or comatose condition. Wasting advances rapidly, abortion occurs in pregnant females, the weakness becomes extreme, the animal remains constantly down, unable to rise, rests his head on the ground, breathes heavily and stertorously and perishes with or without convulsions.

Diagnosis in Cattle. Individual symptoms of cattle plague may be found in other diseases, but the aggregate symptoms, in a rapidly spreading and fatal affection, and connected with a previous prevalence of the disease in the country or district, or distinct evidence of the introduction of infection should in every case obviate error. The chief diagnostic symptoms are: a sudden, very marked rise of temperature; a congestion or blush of the visible mucosæ generally (mouth, nose, vulva, eyes); the formation of white curd-like epithelial concretions on the inside of the lips, dental pad, or gums of the incisors; the formation of red spots or petechiæ on the mucosæ; later the desquamation of the softened epithelium with the formation of erosions or even ulcers; the wart-like rounded epidermic eruptions on the skin; the great abdominal tenderness with tucking up of the abdomen, and sudden arrest of the expiration with a sharp clicking sound and moan; the fœtid, watery diarrhœa and exposure of the dark red, congested and hæmorrhagic rectal mucosa; the discharge from nose, mouth and eyes; the characteristic fever odor; and the rapid progress of the disease from animal to animal, and to a fatal issue. The rapidly advancing contagion and its fatality in cattle, sheep and goats, together with the immunity of horses, dogs, birds and human beings are important elements in diagnosis.

Malignant Catarrh of Cattle is distinguished by the absence of active contagion, one or two only in a herd being attacked; by the absence of the curd-like concretions on lips, dental pad, and gums; by the involving of the matrix of the frontal horns; by the great congestion, swelling and discharge from the eyes; and by the impossibility or improbability of the cattle plague contagion in the particular locality. In localities where cattle plague actually prevails, it may sometimes be impossible to distinguish at first, and then every precaution should be taken to prevent diffusion of infection in case it should be cattle plague.

Thrush of the mouth, though causing an eruption of the same kind, occurs in sucklings only, is unattended by fever, marked congestion, or severe abdominal symptoms.

Foot and Mouth Disease, though equally contagious, and spreading with the same rapidity, is easily distinguished by the very slight hyperthermia, the vesicular character of the mouth and mammary eruption (the cuticle being raised by an abundant clear straw-colored liquid exudate); by the absence, in nearly all cases, of severe abdominal disorder; by the all but constant vesiculation of the interdigital space, and by its mild and non-fatal issue. Swine contract it as readily as cattle and sheep, and horses, dogs, birds and men by inoculation.

Dysentery is marked by the absence of the early, abrupt hyperthermia, though the temperature may rise gradually to a high point; also of the curd-like concretions on the buccal mucosa; by the earlier onset of the fœtid diarrhœa, and by the indisposition to contagious diffusion apart from the confined, foul, crowded buildings. The lesions are mainly on the large intestines while in cattle plague they are on the small intestines, fourth stomach, mouth, throat and skin.

Gastro-enteritis and Stomatitis from corrosive agents and irritant bacteria, can be traced to a definite local cause, do not extend beyond the herd or animal poisoned, and usually occur where the possibility of cattle plague can be excluded. There is usually an entire absence of the white epithelial concretions, of the blush of the mucosæ generally, and of the wart-like epidermic proliferation.

Anthrax of the alimentary tract and rectum is distinguished by the fact that it is largely an enzoötic disease, not spreading widely by simple contact; that it is easily transmissible to horse, dog and man; that it lacks the buccal epithelial concretions and characteristic desquamations and the warty-like skin products; that it shows marked enlargement and engorgement of the spleen; and that the blood and local lesions contain the large sized, square ended anthrax bacillus.