Diseases of cattle, sheep, goats and swine

by G. Moussu; Jno. A. W. Dollar

Lesions. The lesions are sometimes so obscure that the practitioner may hesitate to deliver an opinion.

In acute cases, where death occurs in two or three days, or even in ten to twelve hours, post-mortem examination reveals only increased vascularity of the serous membranes—the peritoneum, pleura, pericardium, etc.; and it may be almost impossible to discover anything abnormal in the cord, for although the clots closing the arteries and veins are infected, they are neither separated from the walls of the vessels nor broken up.

On the surface of the urachus, at the base of the bladder, and in the depths of the peritoneal folds supporting the allantoid arteries (sometimes also the hepatic vein), unequivocal signs of local ascending infection may, however, almost always be found, together with intense injection of the capillaries, little hæmorrhagic spots, and commencing formation of false membranes, etc.

The infection extends also by the lymphatic vessels contained in these peritoneal folds, and finally attains the sublumbar region.

When the disease develops less rapidly the peritoneal cavity contains a certain quantity of blood-stained serosity, as do the pleuræ and pericardium, whilst vascular engorgement of the serous membranes is extremely marked. The intestine shows traces of congestion and inflammation throughout its length, and its contents contain the specific organism in very large numbers.

Finally, in the chronic forms, the serous membranes and the intestine seem only slightly attacked, possibly because the lesions have undergone retrogressive changes. The striking features are the secondary lesions, such as those of pneumonia, broncho-pneumonia, pericarditis, and abscess formation in the lung.

Nocard gives the following description of the lesions found during his investigation of “white scour” of calves in Ireland (Veterinarian, April, 1902, p. 171; see also Prof. Mettam’s paper, Veterinarian, June, 1902, p. 307):—“The lesions found on autopsy vary according to whether the evolution of the disease has been rapid or slow. One lesion, however, is never absent—that of the navel and the navel vessels. In all the calves attacked we found a large umbilicus with hardened coats enclosing a clot easily broken down, sometimes soft and purulent. In every case, also, we observed blood suffusions, often very extensive, along the course of the umbilical vessels and of the urachus, invading often the posterior third of the bladder. In cases where the evolution had been rapid we found the lesions of true hæmorrhagic septicæmia. All the viscera were congested to excess; their surface was studded with petechiæ, ecchymoses, or subserous blood suffusions. The capillary network of the peritoneum, pleura, and pericardium appeared strongly injected. This lesion was especially marked on the epiploon. The intestine was the seat of intense congestion, especially at the level of the ‘floating colon.’

“The mucous membrane was thickened, gorged with blood, and friable; the solitary glands, thick and protruding, were sometimes transformed into a kind of bloody magma, or they were ulcerated, as in anthrax; the contents of the bowel were mixed with a large quantity of blood. The mucous membrane of the fourth stomach was altered nearly to the same degree; it was studded with interstitial hæmorrhages, especially above the level of the open edge of its folds. The mesenteric glands—especially those of the colon—were enormous, gorged with blood, reddish, and often hæmorrhagic. The mucous membrane of the bladder was often covered with petechiæ, the urine which it contained was clear and limpid, but always rich in albumen. [In one sample which was analysed, the urine contained more than 4 grammes of albumen to the litre.] The lungs were gorged with blood, like the intestines; sometimes they were manifestly œdematous, but generally their tissue was still supple, elastic, permeable, and without apparent lesion.

“In the subacute forms the lesions are much less marked. The mucous membrane of the intestine is less congested; sometimes œdema of the submucous tissue exists. The mucous membrane of the fourth stomach is often punctuated with brownish-red patches, traces of the capillary hæmorrhages which were produced at the onset of the disease. The mesenteric glands are swollen, gorged with serum, but not hæmorrhagic; the liver is large and of a yellowish tint; the spleen is little altered; the urine always contains albumen; the lungs are seldom quite sound; they usually contain here and there small diffuse centres of catarrhal pneumonia, of nodular bronchial pneumonia, or simply of atelectasis.

“These lesions are more constant and more dense if the animals have resisted the disease for some time; they then constitute the transition stage between the simple collapse at the beginning of the disease and the suppurating lesion of lung disease. The joint lesions when they exist are very interesting. At the beginning all the periarticular tissues are infiltrated with a yellowish gelatinous serosity. The synovial membrane is covered with vascular aborisations of an extreme richness, which extend on to the articular cartilages. The synovial capsules are distended by a considerable quantity of thick synovia of a deep yellow or brownish tint, holding in suspension flakes of fibrous exudate more or less dense and abundant. When the lesion is older the synovia is replaced by a thick fibrous exudate, which fills sacculations, and extends between the articular surfaces. In this case the lesion appears identical with that of the arthritis seen in pleuro-pneumonia of sucking calves.”