Part 49

Local lymphatic tuberculosis of comparative interest was encountered a few times. Three cases of cervical adenitis, large enough to be visible, were seen, of which one broke down about two weeks before death, and discharged. The others did not ulcerate through the skin but, contrary to the usual rule for the human being, remained as isolated glands only lightly adherent to one another where they lay adjacent. There was also seen an ulcerating tuberculous lymph node in the groin of one monkey, the animal having rather pronounced abdominal and pelvic tuberculosis. Two instances of tonsillar tuberculosis are recorded, in both of which the lesion was of some duration and associated with caseation in the lymph node lying immediately behind and below it. A Guinea Baboon (_Papio sphinx_) had as an unusual part of his general tuberculosis, an active caseopurulent collection in the antrum of Highmore, which attacked the upper maxilla and immediately adjacent muscle; tubercle bacilli could be demonstrated.

One of the cases of nodular or massive peritoneal tuberculosis is quite like the tumor-forming variety of human adolescents; it is as follows:

Reddish Macaque (_Macacus rufescens_). Caseous tuberculosis of mesentery and spleen; miliary tuberculosis of lungs, pleura and liver; chronic myocarditis. The lymphatic glands of the posterior and superior mediastinum and bronchi are slightly enlarged, soft and anthracotic but do not show any tuberculous change. Both lungs are riddled with small, firm, gray miliary tubercles, some surrounded by a clear mantle of connective tissue. The intervening lung is practically normal. Pleura over base of right lung on both surfaces shows small, pale miliary tubercles. The liver contains various sized miliary tubercles. There is a large caseous mass in posterior end of spleen with adhesions to kidney, stomach and colon. Retroperitoneal glands are much enlarged, firm, homogeneous—probably tuberculosis of a different type. Lesser omentum contains one caseous gland. Few caseous glands in great omentum. In the right iliac region there is a large mass involving many coils of intestine. It is found to arise probably from the ileocecal glands and can be traced along the mesentery to the central lymphatic stalk. The mass involved the tissues of the mesentery and surrounds many coils of intestine. Cecum and first part of colon can be traced over its right side. Rectum is free except on right side where it is lightly attached to the mass. Epicardium is gray and irregularly thickened and the muscle just beneath serous membrane is pale and streaked with red lines.

There have been three cases of tuberculosis of the internal male genital area, one of which was suspected of having been the primary seat of the disease; it was described on page 315. The other two could have been secondary since other points of morbid change were as old or older. One of these cases formed a tumor as large as a goose egg at the vesical neck, obstructing the flow of urine and blocking up the seminal vesical, in consequence of which paralytic distention occurred in the bladder while the vesicles were tightly filled with inspissated semen. A case of Fallopian salpingitis has also been cited. Two instances of cerebral tuberculomata have already been described.

Carnivora. This order has the reputation of being quite resistant to the tubercle bacillus, based upon the relative infrequency among cats and dogs in contrast to cows and swine. Some veterinary statistics cite the incidence up to 5 per cent., and occasional references may be found to tuberculosis in circus lions and tigers. Our records would suggest that in gardens the wild varieties of this order have about as much of the infection as the domestic carnivores, 3.5 per cent. The group is made of six Felidæ, one Viverridæ, three Canidæ, six Procyonidæ, and one Ursidæ. The first family includes a lion, tiger, a jaguar and three smaller cats. The Canidæ are all small foxes. The Procyonidæ are all coatis. The features of this order are the occurrence of the fibroulcerative variety with cavitation in the Felidæ and the caseous nodular abdominal and glandular disease in the coatis. All these animals, even those of the last named variety and pathological type, tend to show some tissue resistance to the tuberculous disease. Connective tissue activity is characteristic of the process, considerable distortion being produced by the fibrosis. This feature is borne out where the tissues are studied microscopically. Definite milia are sometimes found, but they consist of epithelioid and round cells with imperfect caseation, giant cells being often missing. About the miliary tubercles a diffuse and not essentially specific tuberculous granulation tissue is found, mixed with which is much connective tissue growth. The fibrotic adhesion-forming serous membrane tuberculosis of carnivores seems worthy of emphasis by the citing of a case in point. White nosed coati (_Nasua narica_), was received in poor condition and died in a few days. Upon dissection a slightly turbid yellowish fluid was found to occupy what remained of the peritoneal cavity which was reduced in size by dense adhesions of the intestines into an inflammatory mass. The omentum was a diffuse thickened apron, also beset with fine tubercles, lying over the mass. Fine young tubercles could also be found upon the intestines and liver while the mesenteric lymph nodes were early in caseation; thoracic organs not infected.

One of the most interesting cases concerned hypertrophic osteitis in a chronically tuberculous lion; the feet are discussed on page 346. This process was described by Marie for human beings many years ago, and was reported in dogs by Cadiot[100] in 1912. This beast was one of five large cats which have died from tuberculosis in its chronic ulcerative form. Three of the cats, one fox and the bear showed definite cavitations of a ragged loculated form. The cavities were usually of the multiple variety and were found in the posterior, that is lower lobe.

Rodentia. The paucity of cases in this order permits little information to be drawn from the form of tuberculosis. The total seems to have been swollen by a group of three beavers, all of which came in one shipment. The remainder were a Capybara and an Agouti. The general type is that of much caseation with little or no surrounding fibrosis. One illustrative case is cited:

American Beaver (_Castor canadensis_). General tuberculosis. The animal presents generalized tuberculosis. The regional lymph nodes show caseous nodules. The right hip joint shows caseous material about the acetabulum with necrosis and pathological fractures in the os innominatum immediately above the acetabulum and including its cavity. Lungs show almost no normal respiratory tissue, the process being a diffuse precaseous, partly gelatinous pneumonic phthisis. The superior and posterior mediastina show caseous glands. There is miliary tuberculosis of the liver. Nodular caseous tuberculosis of the spleen with small tubercles and some cirrhosis of the intervening tissue. There are caseous nodules in all perirenal glands and in the kidney cortices. The psoas muscle glands are densely caseous. The pelvic organs except about the right acetabulum escape involvement. Adrenals not opened but probably not involved.

Ungulata. This order shows the most definite figures among those for the order of mammals. Nearly one-tenth of the whole number of specimens have had some form of tuberculosis and of a very definite character. It is well at first to mention, however, that only four of thirteen families are represented, from which four came 328 of the total 365 autopsies. The remaining thirty-seven were such animals as tapirs, giraffes, swine, and peccaries, in all of which tuberculosis has been reported from elsewhere.

Pulmonary disease with less prominent lesions in other organs, especially the intestines and their related glands, speaks in favor of the aerogenic route being the common one. This of course has been a bone of contention among veterinarians, and I do not presume to settle the matter with these figures.

This order resists tuberculosis to a certain degree as attested by the fibroulcerative character of the majority of the cases. Two instances, one in a buffalo and one in a deer, showed very highly fibrotic pulmonary lesions with a partial attempt to surround and wall off numerous areas of caseation. So too in this order there is a greater tendency to calcification, both in the intra- and extrapulmonary nodes. It is to be emphasized that in our material the thoracic lymph nodes are affected more than the abdominal and regional as 3 to 1. The apparent immunity of the spleen of this order is well illustrated.

The paucity of serous surface involvements in the wild Bovidæ and their prominence in the Cervidæ cannot be ignored in the figures, but it seems misleading since pleural growths and adhesions are quite common in the domestic Bovidæ. The case in the Equidæ was that of a Zebra with a large tuberculous abscess in the retroperitoneal glands forming a tumor in the left renal region. It was quite well surrounded by fibrosis, and the infection had not extended; it seemed quite recent. Analysis of the figures for the remaining three families of ungulates offers little for contrast and much for comparison; it is the usual picture as seen in the domestic cow. Some special cases are worthy of review.

An interesting specimen of softened glands chiefly on one side of the neck was found in a Fallow deer (_Cervus dama_). It resembled the juvenile human cases that require surgical attention. Although palpable lymph nodes can be found in practically all cases of generalized tuberculosis in the Ungulata, this is the only case in our records in which they have presented a large tumefaction and broken down. Pulmonary cavitation is recorded but thrice, one for each of the last three families. Fibrocaseous tuberculosis of the testes was discovered in a Nylghaie (_Boselaphus tragocamelus_), but there is no knowledge of mating or offspring. An ischiorectal abscess was found in an American Bison (_Bison bison_) showing nodular precaseous tubercles of the lung. The former was the cause of death. No tubercle bacilli could be found in the abscess contents, so that the tuberculous basis is inferred, not proven. Tuberculous salpingitis in a Nylghaie was discussed on page 306.

Proboscidea. Eber mentions in the article already referred to that there are three reports in the literature of tuberculosis in elephants. When looking for an explanation of tuberculosis in this animal it must be remembered that it is one of the most attractive objects in a zoological garden and receives perhaps more attention, including feeding, from visitors than any other specimen. The beast while possessing some tissue resistance to tuberculosis, is by no means immune thereto, as has been thought by some persons on account of its reputed longevity, and therefore he is to be protected from infection just as much as other animals. It would appear that he may present caseous pneumonia or nodular caseous disseminated lesions. Our two cases, in animals at the Garden twenty and thirty-eight years respectively, were both of the fibrocaseous variety; the lesion was confined to the lungs. A brief description of their lesions is as follows:

Indian Elephant (_Elephas indicus_) ♂ . Chronic polyarthritis. Chronic myocarditis. Chronic hepatitis (cirrhosis). Parenchymatous nephritis. Chronic tuberculosis of the lungs, partly encapsulated. Pigmentation of the spleen. The pleuræ are very fat but the surfaces are smooth and devoid of adhesions. The lymph nodes of the mediastinum are about 10 × 20 cm. for the largest while the smaller ones vary around 2 × 4 cm. They are firm, deep red-brown without clear divisions into medulla and follicular cortex. There are several large, firm, pale rather cheesy follicles in all the large ones and a few of the small. These do not appear like tuberculosis. The lungs are flaccid and soft; gray and red mottled. The bronchi are firm and stand open. Around one in the upper lobe of the right lung, there is a large area of cheesy degeneration around which a zone of connective tissue has formed. This extends about the bronchus about halfway in a sheath-like manner. There is also a separate nodule the size of a cherry with a cheesy centre. The trachea appears normal. Tubercle bacilli could be demonstrated in the cheesy material. Microscopic section of lung around the cheesy area shows a low grade chronic granulation tissue in some places enclosing cheesy masses with giant cells on the margin. The neighboring septa are slightly thickened and in some places broken, forming emphysematous cavities. Some of these cavities are edematous.

Indian Elephant (_Elephas indicus_) ♀ . Miliary and conglomerate caseous tuberculosis of lung. Edema of lungs. Endarteritis deformans of lung. Cloudy swelling of liver. Chronic passive congestion of liver. Hemosiderin pigmentation of liver. Acute parenchymatous nephritis. Chronic passive congestion of spleen. Chronic hyaline perisplenitis. Multiple calcified fibroid tumors of uterus. Leiomyoma of uterine cornu. Senile atrophy of ovaries. Acute catarrhal enteritis. There are some adhesions of the upper lobes of the lung to the ribs. The lungs are large, increased in weight, color pink and mottled red, air content diminished. There are several masses of tubercles, each as large as a cocoanut, in both lobes. In one such the tubercles are yellow and caseous; some are fibroid but none are liquefied or calcified. The fibrous tissue of the lung parenchyma here is much overgrown. In one instance the terminus of a bronchus is solidly plugged by caseous material. Mucosa of bronchi is reddened, markedly ulcerated, ulcers overlaid by mucopus.

INDIVIDUAL FEATURES OF AVIAN TUBERCULOSIS.

The avian form of tuberculosis is somewhat peculiar in its physical appearance as well as in its distribution. The isolated nodular type is far and away more common by more than 100 per cent. than all the other types combined. These nodules are usually well circumscribed, and to the naked eye suggest that they have a restraining fibroid wall. This is, however, not the case, the impression being due to the dense but actively growing fibrocellular cortical zone of the tubercle. The centre of the nodule, instead of having the soft character like Camembert cheese, resembles the firm but brittle American dairy cheese. Upon opening such an area the central necrotic mass may split away from its cortex and even shell out, leaving a cavity lined by a gray-yellow membrane. These characters are best displayed in nodules of moderate size, the small ones being like the yellow mammalian analogue, the large being like indefinite cheesy masses. In the surrounding tissue evidences of inflammatory processes seem decidedly greater in our material than I am accustomed to see in human and veterinary pathology. This, it seems, should be emphasized since secondary infection with pus cocci and other pathogenic germs appears less often in birds than in mammals.

The difference speaks, therefore for a difference either in the tubercle bacillus of birds or the avian physiology. Judging by the limited morbid processes produced by injecting avian bacilli into rabbits and guinea- pigs the reaction of the bird itself would not seem wholly responsible for the difference. The local tissue reaction in all avian lesions is mononuclear and fibrous, softening and pus being rare. It would seem from this and similar operations that the bird expresses its resistance to the bacteria by a fibrocellular reaction which goes on to fibrosis without softening; perhaps this means also that their polynuclears are not sufficiently active, but the pathogenic power of the bacillus itself doubtless is individualistic.

The character of the cheesy degeneration is likewise different from the mammalian. It seems like an abrupt hyaline necrosis of a large central mass and not the slower cell death seen in the other types of tubercle. At times the degenerated area, instead of having the yellowish color of caseation, will present what we have designated “gelatinous tuberculosis,” the whole infiltrated area resembling boiled sago or tapioca. This seems to be a complete homogeneous coagulation or hyaline necrosis of the whole mass out to the delicate fibrous mantle supplied by the tissue in which the tubercle lies.

The organic distribution of tuberculous lesions has already received some attention and is to be discussed with the orders. There are, however, some localities affected conspicuously in the bird. The skin lesions often attract attention during life. They occur around the eye, at wing joints, on the cresta sterni and on the legs. Parrots and jays have shown nodular or diffuse growths around the eye, originating both in the lids and orbit, which on section have proved to be tuberculous. These seldom ulcerate, but those upon the skin of the breast and wings tend to have superficial erosions or deep ulcers. The latter lesions are more common upon pigeons but have been seen in Psittaci and Galli. Toucans and pigeons when pinioned, have on three occasions shown a tuberculous mass on the stump.

Two parrots with hyperkeratosis of the beak and of the skin of the feet, have also had tuberculosis. These have been mentioned in literature as of tuberculous origin. One case well studied failed to show tubercle bacilli in the corns. In the absence of tubercle bacilli, one is inclined to think that this might be explained on the basis of a circulating toxin such as is assumed to be responsible for hypertrophic periosteitis. This latter condition has not been seen in birds.

Still another type of occasional occurrence deserves mention. While most of the lesions in birds correspond to the description given in the preceding pages, some lesions fail to degenerate in the centre, retaining instead a solid homogeneous fleshy character of dull gray- yellow color. Upon section these have been found wholly cellular in construction. To distinguish them from the ordinary nodules they have been designated tuberculomata. Lesions of this kind may occur along the lymphatic paths, indeed seem more common in the lateral cervical and thoracic chain, and upon bones and nerves. When they are numerous the nodular caseous type is inconspicuous. They suggest the bovine infection (Pearl disease), but one attempt to prove this failed. We are of the opinion that this is the avian lymphatic form, as our examples correspond to the literary descriptions of cervical tuberculous lymphatics in birds. No especial variety of bird is more often affected by this process.

Intestinal tuberculosis among the Aves may be said to assume three forms. The best known, indeed the form usually spoken of as representing the common picture, is that which produces varying sized nodules upon the serosa, sometimes associated with adhesions to neighboring intestines. Just how this type develops is not known. In some quarters it is believed to originate by the penetration of the tuberculous granulation tissue from the mucosa through the intestinal wall by following lymphatic channels and that irregular contractions of the musculature squeeze the exudate outward under the serosa. Other observers think that the bacilli are carried _via_ the lymphatics to the superitoneal tissue, there starting the tubercle. The truth of the matter will probably be that both methods are operative although we have seen more cases suggestive of the second than of the first explanation. When these peritoneal nodules are numerous and prominent, mucosal ulcers are uncommon and _vice versa_.

The second form is the ulcerative, flat ragged or crateriform defect situated in a diffusely thickened wall. This was well illustrated in cases of pulmonary infection in doves and guans, suggesting reinfection of the gut tract from swallowed tubercle bacilli or a backward development of the disease after the lungs were nearly solid.

The third form of tuberculous enteritis is quite interesting and striking. It is best seen in the duodenal loop but may occur anywhere. Diffuse thickening of the enteric wall is noted, and when palpation is practiced a resilient but leathery sensation is obtained. Careful inspection reveals the mucous surface to be velvety, a condition due to a swelling, that is widening, of the villi which retain their erect position and, when washed in flowing water, will be seen to move like a field of grain in a breeze. The serosa may be, usually is, negative. Studied microscopically the peculiarity of this form is in the development of tubercles and diffuse cellular exudation in the villus stalk, sometimes extending into the submucosa also. Round cell masses like lymph follicles are sometimes prominent. This form is not associated with any peculiar organic distribution so far as my studies go.

Passeres. The peculiarity of this order seems to be in the predominance of the pulmonary route as origin of tuberculosis. Perhaps in no other order has there been such extensive and advanced lesions as in these little birds. Sometimes one whole lung will be solid while its fellow will be half occupied by caseous material. The doves alone seem to approximate the Passeres in ability to live with so much tuberculous exudate.

Picariæ. Specimens from this order illustrate well the intestinal origin and distribution of tuberculosis. There was, among these birds, one case showing tuberculomata which was, because of its gross anatomy, listed as the pearl type. Its description is as follows: