avian diphtheria and contagious epithelioma

3
ABSTRACTS. AVIAN DIPHTHERIA AND CONTAGIOUS EPITHELIOMA. IN a recent work, Carnwath puts forward the view that avian diphtheria and contagious epithelioma are identical, basing his conclusion on certain experi- ments of his own and on other published observations. Fally expresses his surprise at this view, which is opposed to numerous original investigations regarding the diseases, and to certain researches which he is at the present moment carrying on along with M. Bordet in regard to avian diphtheria. The attention of investigators has already been drawn to the fact that contagious epithelioma is accompanied by lesions on the buccal membrane, which at one period of development in some degree resemble those of diphtheria. This resemblance, however, appears to be only superficial. and on more thorough investigation does not seem in any way to justify the view that the two conditions are identical. At the present time the two investigators mentioned have animals suffering from both diseases under observation in the Pasteur Institute at Brussels. They had also familiarised themselves by former investigations with the conditions of development of these diseases, and they give a comparative description of the two diseases as observed by themselves, which also appears to agree with that given by most other authors who have looked into the question. Fowl diphtheria and pigeon diphtheria are chronic diseases affecting the mucous membrane but not the skin, as can be proved by experiment. If, for instance, one scrapes off a little of the caseous, pseudo-membranous, yellowish- white exudate from the buccal membrane of a fowl suffering from the natural disease, mixes it with a small quantity of sterile water, and inoculates a healthy fowl on the palate by scarification, changes usually become apparent within twenty-four hours. The point of inoculation shows slight cedematous thickening, and soon becomes covered with a whitish, mucous, adherent exudate. During the following days the exudate develops more and more, grows thicker, and assumes the typical appearance of diphtheritic pseudo- membranes. Healthy subjects, however, do not all take the disease with equal readiness, some showing a certain degree of natural immunity; so that while certain subjects exhibit wasting, and die at the end of a varying time in consequence of extension of the buccal lesions, others recover spontaneously and become completely refractory to subsequent inoculation with purulent material. The authors were unable to transmit the diphtheria of fowls to pigeons, or vice versa. When examined microscopically, the caseous exudate is seen. to consist of a mixture of epithelial cells, red and white hlood corpuscles, fragments of dead tissue, and very varying numbers of different micro-organisms, among which is often found a diphtheritic microbe. The latter has been regarded by several writers as the actual cause of the disease. In attempting to isolate the specific microbe, the investigator3 naturally sought some disease product which was free from this great degree of variability as regards its microbic contents. They therefore endeavoured to localise the disease in other parts of the body, and at first in the skin, applying the natural virus to scarifications made in the skin covering the chest. This produced a very trifling eschar covered by purulent exudate; the eschar dried up rapidly and exfoliated in about four or five days, leaving behind a well-defined cicatrix. Such a lesion is not characteristic of diphtheria, and cannot be utilised for

Upload: lydien

Post on 02-Jan-2017

217 views

Category:

Documents


1 download

TRANSCRIPT

ABSTRACTS.

AVIAN DIPHTHERIA AND CONTAGIOUS EPITHELIOMA.

IN a recent work, Carnwath puts forward the view that avian diphtheria and contagious epithelioma are identical, basing his conclusion on certain experi­ments of his own and on other published observations.

Fally expresses his surprise at this view, which is opposed to numerous original investigations regarding the diseases, and to certain researches which he is at the present moment carrying on along with M. Bordet in regard to avian diphtheria.

The attention of investigators has already been drawn to the fact that contagious epithelioma is accompanied by lesions on the buccal membrane, which at one period of development in some degree resemble those of diphtheria. This resemblance, however, appears to be only superficial. and on more thorough investigation does not seem in any way to justify the view that the two conditions are identical.

At the present time the two investigators mentioned have animals suffering from both diseases under observation in the Pasteur Institute at Brussels. They had also familiarised themselves by former investigations with the conditions of development of these diseases, and they give a comparative description of the two diseases as observed by themselves, which also appears to agree with that given by most other authors who have looked into the question.

Fowl diphtheria and pigeon diphtheria are chronic diseases affecting the mucous membrane but not the skin, as can be proved by experiment. If, for instance, one scrapes off a little of the caseous, pseudo-membranous, yellowish­white exudate from the buccal membrane of a fowl suffering from the natural disease, mixes it with a small quantity of sterile water, and inoculates a healthy fowl on the palate by scarification, changes usually become apparent within twenty-four hours. The point of inoculation shows slight cedematous thickening, and soon becomes covered with a whitish, mucous, adherent exudate. During the following days the exudate develops more and more, grows thicker, and assumes the typical appearance of diphtheritic pseudo­membranes.

Healthy subjects, however, do not all take the disease with equal readiness, some showing a certain degree of natural immunity; so that while certain subjects exhibit wasting, and die at the end of a varying time in consequence of extension of the buccal lesions, others recover spontaneously and become completely refractory to subsequent inoculation with purulent material. The authors were unable to transmit the diphtheria of fowls to pigeons, or vice versa.

When examined microscopically, the caseous exudate is seen. to consist of a mixture of epithelial cells, red and white hlood corpuscles, fragments of dead tissue, and very varying numbers of different micro-organisms, among which is often found a diphtheritic microbe. The latter has been regarded by several writers as the actual cause of the disease.

In attempting to isolate the specific microbe, the investigator3 naturally sought some disease product which was free from this great degree of variability as regards its microbic contents.

They therefore endeavoured to localise the disease in other parts of the body, and at first in the skin, applying the natural virus to scarifications made in the skin covering the chest. This produced a very trifling eschar covered by purulent exudate; the eschar dried up rapidly and exfoliated in about four or five days, leaving behind a well-defined cicatrix.

Such a lesion is not characteristic of diphtheria, and cannot be utilised for

ABSTRACTS.

any useful purpose. No greater success was obtained when inoculations were made on the comb. The authors therefore had recourse to hypodermic injections of the virus, as it is known that certain writers have in this way isolated a cocco-bacillus which they regard as specific. The authors found that when they injected subcutaneously small quantities of a weak emulsion, trifling local cedema developed on the succeeding day, but rapidly diminished, so that at the end of tel'! days only a little nodule containing caseous material remained, and no general symptoms whatever developed.

When, on the contrary, they injected larger doses of the virus, an inflam­matory centre developed at the point of injection, as indicated by a warm swelling, bluish in tint, and accompanied by emphysema. The bird appeared dull, huddled itself up in a ball with its feathers staring, refused all food, suffered from greenish diarrhcea, walked unsteadily, became paralysed, re­mained resting on its hocks, and died in from three to five days.

The post-mortem examination revealed at the point of inoculation a gangrenous centre which exhaled a very repulsive odour. On microscopic examination several species of micro-organisms were found, among which was a cocco-bacillus.

No lesions were found in the internal organs or on the serous membranes. The bird was in a very wasted condition.

From the heart's blood a cocco-bacillus was isolated, which was probably the cause of the septicremia causing death, but which had no kind of resem­blance to that of avian diphtheria. The blood of fowls which thus died after hypodermic injection did not reproduce characteristic diphtheria when inocu­lated on mucous membranes.

Injection of the virus into one of the air sacs, however, caused lesions similar to those on the mucous menibrane, from which the material had been taken.

At this s'age in their experiments the authors inoculated the membrana nictitans, sometimes by scarification, sometimes by passing through it an infected thread of silk. In such case the disease becomes localised, producing a chronic conjunctivitis with periocular swelling and occasionally more severe complications, such as keratitis, ulceration of the cornea, and caseous exuda­tion.

The experimental reproduction of the disease by means of fragments of the membrana nictitans, the re,ults of microscopic examination, the cultivation on a special medium, and the isolation of the micro·organism have been de­scribed by M. Bordet in an article read before the Society of Medical and Natural Science at Brussels.

It will be seen, therefore, that diphtheria in the fowl is a chronic microbic inflammation of the mucous membranes, and during the course of the' numerqus inoculations the authors have made they have never seen any cutaneous lesions resembling those of epithelioma.

Although' the nature of the contagium of epithelioma (also known as variola of birds, and formerly gregarinous diphtheria) is at present unknown, we possess some very exact information enabling one to study it as a perfectly well-defined disease condition,

It is an eruptive disease which principally affects young pigeons, and most commonly develops on those portions of the head not covered by feathers, such as the nostrils, openings of the ears, commisures of the beak, the crest, and particularly the margins of the eyelids. In these positions it produces little, rounded, firm, tubercle-like new growths, the caseous centres of which project above the general surface of the swelling.

This malignant new growth attacks all parts of the skin, and has been classed by Borrel in the group of infectious epithelioses. It is transmitted with great facility to healthy subjects. If a little of the diluted virus from a

ABSTRACTS.

swelling be smeared over scarifications made in any part of the skin or mucous membranes, the disease is soon reproduced in any bird which has not formerly suffered from it.

The development of the growths can be more closely followed on the buccal mucous membrane (which is often attacked) when a more exact method, such as the intravenous injection of virulent emulsion, is utilised. The mucous membrane first shows a slight reddish swelling, the centre of which becomes yellowish in colour, undergoes caseous degeneration, and is. surrounded by an inflammatory zone. The swelling soon increases in size; its surface becomes covered with a thick whitish-yellow exudate, presenting the appearance of a diphtheritic false membrane.

The fowl is also receptive for the disease, and two of these birds were inoculated by intravenous injection of an emulsion of a swelling removed from a pigeon. At the end of six days one showed typical cutaneous lesions.

The conditions of development of the experimental disease have recently been studied by Burnet, who reproduced it, particularly by ingestion, and dis­covered that the blood and parenchyma of the internal organs were virulent.

In microscopic preparations obtained by cutting the swellings, but particu­larly in scrapings from diseased centres on the conjunctiva, the cytoplasm of the epithelial cells shows, close to the nucleus, large masses of granules, sometimes resembling a mulberry, sometimes distributed in the form of coloured grains. These intra-epithelial bodies, common to all infectious epi­thelioses, are regarded bf certain authors as playing a principal part in the etiology of the disease.

From the above it is clear that whatever method of experimental inoculation is used for the production of diphtheria, the cutaneous growths which characterise epithelioma are never reproduced.

The writers have noted that birds affected with diphtheria very readily contract epithelioma, so that one sometimes finds one animal suffering from both diseases. This, however, would not be sufficient to demonstrate the duality of the two diseases; but the fact that a bird which has recovered from epithelioma can still contract diphtheria, and zlice z'ersa, is a much more certain proof.

It is possible that during Carnwath's experiments some such accident has occurred, the same animal successively suffering from both diseases.

To sum up, the one disease affects the mucous membranes, assumes a chronic course, and does not render the blood virulent; whilst the other attacks not only the mucous membrane but also the integument in general, and is accompanied by the development of characteristic swellings on'the skin and by a virulent condition of the blood. These facts are sufficient clearly to differentiate between the two conditions. -(Fally, Ann. de MM. Vet., February 1908, p. 69.)

BIER'S METHOD IN VETERINARY PRACTICE.

THE method of treatment suggested by Dr Bier consists essentially,in the artificial production of active or passive hypenemia in the diseased area.

"I believe I am right in saying," states Dr Bier in the introduction to his work, .Hyperiimie als Heiimittel, "that anremia never occurs in a part which is in process of destroying a morbid centre or rendering it inoffensive and which succeeds in the process. Such a centre is always traversed or sur­rounded by hyperremic vessels. Thus, if we admit that the reactions of the body are useful manifestations, natural efforts towards cure, we may say that of all the spontaneous curative processes hyperremia is the most common."