Part 64 (1/2)
Garsault in 1746 said that ”as this disease is communicated very easily and can infect in a very short time a prodigious number of horses by means of the discharges which may be licked up, animals infected with glanders should be destroyed.”
Bourgelat, the founder of veterinary schools, in his ”Elements of Hippiatry,” published in 1755, establishes glanders as a virulent disease.
Extensive outbreaks of glanders are described as prevailing in the great armies of continental Europe and England from time to time during the periods of all the wars of the last few centuries.
Glanders was imported into America at the close of the eighteenth century, and before the end of the first half of the last century had spread to a considerable degree among the horses of the Middle and immediately adjoining Southern States. This disease was unknown in Mexico until carried there during the Mexican War by the badly diseased horses of the United States Army. During the first half of the last century a large body of veterinarians and medical men protested against the contagious character of the disease, and by their opinion prevailed to such an extent against the common opinion that several of the Governments of Europe undertook a series of experiments to determine the right between the contesting parties.
At the veterinary school at Alfort and at the farm of Lamirault in France several hundred horses which had pa.s.sed examination as sound had placed among them glandered horses under various conditions. The results of these experiments proved conclusively the contagious character of the disease.
In 1881 Bouchard, of the faculty of medicine in Paris, a.s.sisted by Capitan and Charrin, undertook a series of experiments with matter taken from the farcy ulcer of a human being. They afterwards continued their experiments with matter taken from horses, and in 1883 succeeded in showing that glanders is caused by a bacterium which is capable of propagation and reproduction of others of its own kind if placed in the proper media. In 1882 the specific germ of glanders was first discovered and described by Loeffler and Schuetz in Germany.
When we come to study the etiology of glanders, the difference of susceptibility on the part of different species of animals, or even on the part of individuals of the same species, and when we come to find proof of the slow incubation and latent character of the disease as it exists in certain individuals, we understand how in a section of country containing a number of glandered animals others can seem to contract and develop the disease without having apparently been exposed to contagion.
_Causes._--The contagious nature of glanders, in no matter what form it appears, being to-day definitely demonstrated, we can recognize but one cause for all cases, and that is contagion by means of the specific virus of the disease. The causative organism is known as the _Bacillus mallei_.
In studying the writings of the older authors on glanders, and the works of those authors who contested the contagious nature of the disease, we find a large number of predisposing causes a.s.signed as factors in the development of the malady.
While a virus from a case of glanders if inoculated into an animal of the genus _Equus_ will inevitably produce the disease, we find a vast difference in the contagious activity of different cases of glanders. We find a great variation in the manner and rapidity of the development of the disease in different individuals and that the contagion is much more liable to be carried to sound animals under certain circ.u.mstances than it is under others. Only certain species of animals are susceptible of contracting the disease, and while some of these contract it as a general const.i.tutional malady, in others it develops as only a local sore.
In acute glanders the contagion is found in its most virulent form, as is shown by the inevitable infection of susceptible animals inoculated with the disease, while the discharge from chronic semilatent glanders and farcy may at times be inoculated with a negative result; again, in acute glanders, as we have a free discharge, a much greater quant.i.ty of virus-containing matter is scattered in the neighborhood of an infected horse to serve as a contagion to others than is found in the small amount of discharge of the chronic cases.
The chances of contagion are much greater when sound horses, a.s.ses, or mules are placed in the immediate neighborhood of glandered horses, drink from the same bucket, stand in the next stall, or work in the same wagon, or are fed from feed boxes or mangers which have been impregnated by the saliva and soiled by the discharge of sick animals. Transmission occurs by direct contact of the discharges of a glandered animal with the tissues of a sound one, either on the exterior, when swallowed mixed with feed into the digestive tract, or when dried and inhaled as dust.
The stable attendants serve as one of the most common carriers of the virus. Dried or fresh discharges are collected from the infected animals in cleaning, harnessing, feeding, and by means of the hands, clothing, the teeth of the currycomb, the sponge, the bridle, and the halter, and are thus carried to other animals.
An animal affected with chronic glanders in a latent form is moved from one part of the stable to another, or works. .h.i.tched with one horse and then with another, and may be an active agent in the spreading of the disease without the cause being recognized.
Glanders is found frequently in the most insidious forms, and we recognize that it can exist without being apparent; that is, it may affect a horse for a long period without showing any symptoms that will allow even the most experienced veterinarian to make a diagnosis. An old gray mare belonging to a tavern keeper was reserved for family use with good care and light work for a period of eight years, during which time other horses in the tavern stable were from time to time affected with glanders without an apparent cause. The mare, whose only trouble was an apparent attack of heaves, was sold to a huckster who placed her at hard work. Want of feed and overwork and exposure rapidly developed a case of acute glanders, from which the animal died, and at the autopsy were found the lesions of an acute pneumonia of glanders grafted on chronic lesions, consisting of old nodules which had undoubtedly existed for years.
In a case that once came under the care of the writer, a coach horse was examined for soundness and pa.s.sed as sound by a prominent veterinarian, who a few months afterwards treated the horse for a skin eruption from which it recovered. Twelve months afterwards it came into the hands of the writer, hidebound, with a slight cough and a slight eruption of the skin, which was attributed to clipping and the rubbing of the harness, but which had nothing suspicious in its character. The horse was placed on tonics and put to regular light driving. In six weeks it developed a bronchitis without having been specially exposed, and in two days this trouble was followed by a lobular pneumonia and the breaking of an abscess in the right lung. Farcy buds developed on the surface of the body and the animal died. The autopsy showed the existence of a number of old glanderous nodules in the lungs which must have existed previous to purchase, more than a year before.
Public watering troughs and the feed boxes of boarding stables and the tavern stables of market towns are among the most common recipients for the virus of glanders, which is most dangerous in its fresh state, but cases have been known to be caused by feeding animals in the box or stall in which glandered animals had stood several months before. While the discharge from a case of chronic glanders is much less liable to contain many active bacilli than that from a case of acute glanders, the former, if it infects an animal, will produce the same disease as the latter. It may a.s.sume from the outset an acute or chronic form, according to the susceptibility of the animal infected, and this does not depend upon the character of the disease from which the virus was derived.
The animals of the genus _Equus_--the horse, the a.s.s, and the mule--are those which are the most susceptible to contract glanders, but in these we find a much greater receptivity in the a.s.s and mule than we do in the horse. In the a.s.s and mule in almost all cases the period of incubation is short and the disease develops in an acute form. We find that the kind of horse infected has an influence on the character of the disease; in full-blooded, fat horses of a sanguinary temperament, the disease usually develops in an acute form, while in the lymphatic, cold-blooded, more common race of horses the disease usually a.s.sumes a chronic form.
If the disease develops first in the chronic form in a horse in fair condition, starvation and overwork are liable to bring on an acute attack, but when the disease is inoculated into a debilitated and impoverished animal it is apt to start in the latent form. Inoculation on the lips or the exterior of the animal is frequently followed by an acute attack, while infection by ingestion of the virus and inoculation by means of the digestive tract is often followed by the trouble in the chronic latent form.
In the dog the inoculation of glanders may develop a const.i.tutional disease with all the symptoms which are found in the horse, but more frequently the virus pullulates only at the point of inoculation, remaining for some time as a local sore, which may then heal, leaving a perfectly sound animal; but while the local sore is continuing to ulcerate, and specific virus exists in it, it may be the carrier of contagion to other animals. In man we find a greater receptivity to glanders than in the dog, and in many unfortunate cases the virus spreads from the point of inoculation to the entire system and destroys the wretched mortal by extensive ulcers of the face and hemorrhage or by destruction of the lung tissue; in other cases, however, glanders may develop, as in the dog, in local form only, not infecting the const.i.tution and terminating in recovery, while the specific ulcer by proper treatment is turned into a simple one. In the feline species glanders is more destructive than in the dog. The point of inoculation ulcerates rapidly and the entire system becomes infected.
While a student the writer saw a lion in the service of Prof. Trasbot, at Alfort, which had contracted the disease by eating glandered meat and died with the lung riddled with nodules. A litter of kittens lapped the blood from the lungs of a glandered horse on which an autopsy was being made, and in four days almost their entire faces, including the nasal bones, were eaten away by rapid ulceration. Nodules were found in the lungs. A pack of wolves in the Philadelphia Zoological Garden died in 10 days after being fed with the meat of a glandered horse. The rabbit, guinea pig, and mice are especially susceptible to the inoculation of glanders, and these animals are convenient witnesses and proofs of the existence of suspected cases of the glanders in other animals by the results of successful inoculations.
The primary lesion in any form is a local point in which occurs a rapid proliferation of the cell elements which make up the animal tissue with formation of new connective tissue, with a crowding together of the elements until their own pressure on one another cuts off the circulation and nutrition, and death takes place in them in the form of ulceration or gangrene. Following this primary lesion we have an extension of infection by means of the spread of the bacilli into those tissues immediately surrounding the first infected spot, which are most suitable for the development of simple inflammatory phenomena or the specific virus. The primary symptoms are the result of specific reaction at the point of inoculation, but at a later time the virus is carried by means of the blood vessels and lymphatic vessels to other parts of the body and becomes lodged at different places and develops in them; again, when the disease has existed in the latent form in the lungs of the animal and the virus is wakened into action from any cause, we have it carried to various parts of the body and developing in the most susceptible regions or organs. The points of development are most frequently determined by the activity of the circulation and the effects of exterior irritants. For example, if a horse which has been so slightly affected with the virus of glanders that no symptoms are visible is exposed to cold, rain, or sleet, or by the rubbing of the harness on the body and the irritation of mud on the legs, the disease is liable to develop on the exterior in the form of farcy, while a full-blooded horse which is employed at speed and has its lungs and respiratory tract gorged with blood from the extreme use of these organs will develop glanders as the local manifestation of the disease in the respiratory tract.
The previous reference to the existence of glanders under the two forms more commonly differentiated as glanders and as farcy, and our reference to the various conditions in which it may exist as acute, chronic, and latent, show that the disease may a.s.sume several different phases.
Without for a moment losing sight of the fact that all these varied conditions are identical in their origin and in their essence, for convenience of study we may divide glanders into three cla.s.ses--chronic farcy, chronic glanders, and acute glanders with or without farcy.
CHRONIC FARCY.
_Symptoms._--In farcy the symptoms commence by formation of little nodes on the under surface of the skin, which rapidly infringe on the tissues of the skin itself. These nodes, which are known as farcy ”buds” and farcy ”b.u.t.tons,” are from the size of a bullet to the size of a walnut.
They are hot, sensitive to the touch, at first elastic and afterwards become soft; the tissue is destroyed, and infringing on the substance of the skin the disease produces an ulcer, which is known as a chancre.