Part 69

Suddenly, without the preliminary rales which precede grave lesions of the lungs in other diseases, the blowing murmur of pneumonia is heard over a variable area of the chest, usually, however, much more distinctly over the trachea at the base of the neck and directly behind the shoulder on each side of the chest. In some cases the evidence of lung lesion can be detected only over the trachea. The lesions of the lungs may be scattered throughout both lungs, involving numerous small areas, or they may be confined to and more or less fully occupy one or two lobes. Occasionally there is a general involvement of both lungs. The body temperature has now reached 104 deg. or 105 deg. F., or in extreme cases even a degree higher. The debility of the animal is great without the stupefaction or evidence of cerebral trouble, which is constant with such grave constitutional phenomena in influenza or severe pneumonia. The animal is subject to occasional chills, and staggers in its gait. The yellow coloration of the visible mucous membrane is rendered pale by infiltration of the liquid of the blood into the tissues; the pulse may become so soft as to be almost imperceptible, the heart movement and sounds being at the same time exaggerated. The animal loses flesh rapidly, and dropsies of the extremities, of the under surface of the belly, or of the internal organs may show themselves.

Terminations.—These symptoms may gradually subside after five to eight days, with an improved appetite the inanition may cease and the animal commence to nourish its impoverished blood and tissues; the pulse becomes stronger and the heart more regular and less tumultuous; the mucous membranes assume a brighter and more distinct color; the difficulty of respiration is removed, and the animal may make a recovery. When death occurs it is usually directly due to heart failure; in some cases it is caused by asphyxia, owing to the great amount of exudation into the lung tissue, rendering its further function impossible.

Complications.—The pulmonary complications of infectious pneumonia are secondary inflammatory or necrotic changes in the lungs themselves. Suppuration at times takes place in the bronchi and may extend to the lung tissue. In this case mucous rales develop which are most distinctly heard over the trachea and on the sides of the chest directly behind the shoulders. With the development of the mucous rales, to be heard on auscultation, we have a more purulent discharge from the nostrils, similar to that of a chronic or subacute bronchitis. If the inflammation has been of some standing, cavernous rales may be heard, indicating the destruction of a considerable portion of lung tissue and the formation of a cavity. The effects of this more acute inflammatory process are not appreciable in the general condition of the animal, except to weaken it still further and add to its debilitated and emaciated cachexia. Gangrene sometimes occurs. A sudden rise of the body temperature of 1 deg. or 2 deg., with a more enfeebled pulse and a still more tumultous heart, develop simultaneously with the appearance of a discharge from the nostrils. This discharge is gray in color, serous or watery in consistency, mixed with the detritus of broken-down lung tissue, and sometimes contains clots of blood, or in more serious cases may be marked by a quantity of fluid blood from a hemorrhage, which proves fatal. The discharge is fetid to the smell. The animal emaciates rapidly. On examination of the lungs mucous rales are heard in the larger bronchi, cavities may be found at any part of these organs, and points of lobular pneumonia may be detected.

A very serious complication is an inflammation of the heart muscle. This is shown by a very weak and rapid pulse, great prostration, some filling of the lungs. This complication nearly always terminates in death. Other complications which may be mentioned are inflammation of the kidneys, blood poisoning, congestion of the brain, and inflammation of the tendinous sheaths and the tendons of the legs.

Diagnosis.—As fever is the first symptom of infectious pneumonia, it is useful during an outbreak of this disease to make daily temperature measurements of the exposed horses, so that the first indication of disease may be discovered and the horse removed from contact with those that are sound.

Prognosis.—The mortality in this disease may be as high as 25 per cent, but it is usually not more than 10 per cent. If there is a special tendency to complications of some sort, the mortality is increased.

Alterations.—At the time of death from infectious pneumonia we frequently find septic changes and the evidences of putrefaction. The solidification of the lung tissue is found irregular in shape and high around the root of the lungs and the large bronchi, and is generally covered by sound lung tissue. The anterior lobes of the lungs are usually entirely affected. The diseased portion appears of a gray-yellowish color, somewhat watery, and tears readily. Matter is found in the air tubes which form gutters through the jellylike mass of the diseased lung. Abscesses from the size of a nut to larger masses may be found throughout the lungs. The blood is dark in color, fluid, or only clotted into soft, jellylike masses. Masses of gangrenous or dead-black tissue may be present.

Treatment.—Bleeding is not to be used, because it would only still further weaken an already enfeebled animal; antimony or the alterants would increase the depression of a too-depraved constitution. There is in this disease no acute congestion of a particular organ to draw off by depletive measures, nor any violent blood current to be retarded, for fear of hypernutrition of any special part.

Revulsives do good, as they excite the nervous system and awaken the torpor of the weakened blood vessels, which aid in the reestablishment of the functions. As in other diseases, mustard poultices may be applied over the belly and sides of the chest, but caution must be used in the employment of blisters, as ugly ulcers may result from their action on a tissue of weakened vitality. Setons are dangerous from the great tendency in this disease to septic complications. Repeated friction of the legs by hand-rubbing and warmth by bandaging and by rubbing the surface of the body with turpentine and alcohol, which is immediately to be dried by rough towels, will excite the circulation and stimulate the emunctories of the skin.

Stimulants are given internally from the outset of the disease. Turpentine in 1-dram doses regulates the heart and excites the kidneys to carry off waste matter, but if repeated too frequently may disturb the already delicate digestive system. Alcohol rectifies the latter danger, and is a useful stimulant to the heart and digestive system, if given with care in small doses. It is an antiputrid, and is especially indicated when septic complications and gangrene are present. The aromatics and bitter tonics are useful; gentian and tea in warm decoction form a useful menstruum for other remedies. Digitalis is a useful remedy. Strychnin and quinin may be given throughout almost the whole course of the disease. The various preparations of iron are astringents and excitants to the digestive system. Carbolic acid is an antiputrid which is of marked benefit in edematous pneumonia; it should be given in small doses diluted in alcohol.

Salicylic acid may be given in 1 or 2 dram doses every few hours. It is much used for troubles of the serous membranes, lowers the temperature, and is of value in this disease in preventing the exudation into the tissue of the lungs. The alkalines, as the sulphate and bicarbonate of soda, the nitrate of potash, and very small doses of the iodid of potash, should be employed to regulate the digestive tract, the kidneys, and the other excreting glands, and to stimulate absorption of the waste matter.

The biological products enumerated under the treatment of the catarrhal form of influenza are also recommended for this disease. The bacterial vaccines in particular are being employed to a great extent, but the results are not uniformly satisfactory, especially with regard to prevention. They might, however, exert a beneficial influence against an attack of the secondary invaders and complications. A serum is also being prepared especially for the treatment of this disease, and since this is obtained from animals which have been highly immunized against the various organisms found in association with influenza it no doubt is beneficial, especially when the life of the animal is threatened. Such serum, however, should be used in sufficiently large doses, as repeated experience has proved that small doses have no beneficial action on the disease.

More recently salvarsan is being highly recommended for the treatment of the pneumonic form of influenza, and by many investigators it is considered as a specific for this affection. A single injection of this preparation is supposed to result in a rapid clearing of the lungs and the recovery of the animal is hastened. The cost of this product, however, at the present time, is exorbitant, and it should be considered only in the treatment of very valuable animals.

The same procedure as given for influenza should be carried out in the prevention of this affection.

The diet demands the strictest attention from the outset. In many of the fevers the feed has to be diminished in quantity and regulated in the quality of its heat-producing components during the acute part of the disease, so as to lessen the material for combustion in the inflamed organs. In edematous pneumonia, on the contrary, all the feed that can possibly be digested and assimilated must be given. Choice must be made of the richest material which can be handled by the weakened stomach and intestines without fatiguing them. Good, sound hay should be chopped short and dampened or partly boiled; in the latter case the hay tea can be reserved to use as a drink. Oats may be preferred dry or in other cases are taken better scalded; in most cases, however, it is better to give slops of oatmeal, to which may be added a little bran, barley flour, or boiled milk and wheat flour. Pure cow's milk, not too rich in fatty matter, may be given alone or with beaten eggs; frequently the horse has to be coaxed with the milk diluted with several parts of water at first, but will soon learn to drink the pure milk. Apples and carrots cut up raw or boiled are useful, and fresh clover in small quantities will frequently stimulate the appetite. In other words, various feeds and combinations should be given to the horse. Throughout the course of the disease and during convalescence the greatest attention must be taken to cleaning the coat thoroughly so as to keep the glands of the skin in working order, and light, warm covering must be used to protect the animal from cold or drafts of air.

STRANGLES.

Synonyms.—Distemper; colt-ill; catarrhal fever; one form of shipping fever; febris pyogenica.

Definition.—Strangles is an infectious disease of the horse, mule, and ass, seen most frequently in young animals, and usually leaving them immune from future trouble of the same kind.

It appears as a fever lasting for a few days, and is usually associated with an abscess formation of lymph glands, especially those under the jaw, which have a tendency to break on the outside. It usually leaves the animal after convalescence perfectly healthy and as good as it was before, but sometimes leaves it a roarer or is followed by the development of deep-seated abscesses which may prove fatal.

Causes.—The cause of strangles is infection by direct contact with an animal suffering from the disease, or indirectly through contact with the discharges from an infected animal, or by means of the atmosphere in which an infected animal has been. There are many predisposing causes which render some animals much more subject to contract the disease than others. Early age, which has given it the popular name of colt-ill, offers many more subjects than the later periods of life do, for the animal can contract the disease but once, and the large majority of adult and old animals have derived an immunity from previous attacks. At 3, 4, or 5 years of age the colt, which has been at home, safe on a meadow or in a cozy barnyard, far from all intercourse with other animals or sources of contagion, is first put to work and driven to the market town or county fairs to be exposed to an atmosphere or to stables contaminated by other horses suffering from disease and serving as infecting agents. If it fails to contract it there, it is sold and shipped in foul, undisinfected railway cars to dealers' stables, equally unclean, where it meets many opportunities of infection. If it escapes so far, it reaches the time for heavier work and daily contact on the streets of towns or large cities, with numerous other horses and mules, some of which are sure to be the bearers of the germs of this or some other infectious disease, and at last it succumbs.

The period of the eruption of the last permanent teeth, or the end of the period of development from the colt to an adult horse, at which time the animals usually have a tendency to fatten and be excessively full-blooded, also seems to be a predisposing period for the contraction of this as well as of the other infectious diseases. Thoroughbred colts are very susceptible, and frequently contract strangles at a somewhat earlier age than those of more humble origin. Mules and asses are much less susceptible and are but rarely affected. Other animals are not subject to this disease, but there is a certain analogy between it and distemper in dogs. After exposure to infection there is a period of incubation of the disease, lasting from two to four days, during which the animal enjoys its ordinary health.

Symptoms.—The horse at first is a little sluggish if used, or when placed in its stable is somewhat dejected, paying but moderate attention to the various disturbing surroundings. Its appetite is somewhat diminished in many cases, while in some cases the animal eats well throughout. Thirst is increased, but not a great deal of water is taken at one time. If a bucket of water is placed in the manger the patient will dip its nose into it and swallow a few mouthfuls, allowing some of it to drip back and then stop, to return to it in a short time. The coat becomes dry and the hairs stand on end. At times the horse will have chills of one or the other leg, the fore quarters, or hind quarters, or in severe cases of the whole body, with trembling of the muscles and dryness of the skin.

If the eyes and mouth are examined the membranes are found reddened to a bright rosy color. The pulse is quickened and the breathing may be slightly accelerated. At the end of two days a cough is heard and a discharge begins to come from the nostrils. This discharge is at first watery; it then becomes thicker, somewhat bluish in color, and sticky, and finally it assumes the yellowish color of matter and increases greatly in quantity.

At the outset the colt may sneeze occasionally and a cough is heard. The cough is at first repeated and harsh, but soon becomes softer and moist as the discharge increases. Again, the cough varies according to the source of the discharge, for in light cases this may be only a catarrh of the nasal canals, or it may be from the throat, the windpipe, or the air tubes of the lungs, or even from the lungs themselves. According to the organ affected the symptoms and character of cough are similar to those of a laryngitis, bronchitis, or lung fever caused by ordinary cold.

Shortly after the discharge is seen a swelling takes place under the jaw, or in the intermaxillary space. This is at first puffy, somewhat hot and tender, and finally becomes distinctly so, and an abscess is felt, or having broken itself the discharge is seen dripping from a small opening. When the discharge from the nostrils has fully developed the fever usually disappears and the animal regains its appetite, unless the swelling is sufficient to interfere with the function of the throat, causing pain on any attempt to swallow. At the end of four or six days the discharge lessens, the soreness around the throat diminishes, the horse regains its appetite, and in two weeks has regained its usual condition. Old and strong horses may have the disease in so light a form that the fever is not noticeable; they may continue to eat and perform their ordinary work as usual and no symptom may be seen beyond a slight discharge from the nose and a rare cough, which is not sufficient to worry any but the most particular owner. But, on the other hand, the disease may assume a malignant form or become complicated so as to become a most serious disease, and even prove fatal in many cases. Inflammation of the larynx and bronchi, if excessive, produce violent, harsh coughing, which may almost asphyxiate the animal. The large amount of discharge may be mixed with air by the difficult breathing, and the nostrils, the front of the animal, manger, and surrounding objects become covered with a white foam. The inflammation may be in the lung itself (lobular pneumonia) and cause the animal to breathe heavily, heave at the flanks, and show great distress. In this condition marked symptoms of fever are seen, the appetite is lost, the coat is dry, the horse stands back in its stall at the end of the halter strap with its neck extended and its legs propped apart to favor breathing. This condition may end by resolution, leaving the horse for some time with a severe cough, or the animal may die from choking up of the lungs (asphyxia).

The swelling under the jaw may be excessive, and if the abscess is not opened it burrows toward the throat or to the side and causes inflammation of the parotid glands and breaks in annoying fistulas at the sides of the throat and even up as high as the ears. Roaring may occur either during a moderately severe attack from inflammation of the throat (larynx), or at a later period as the result of continued lung trouble. Abscesses may develop in other parts of the body, in the poll, in the withers, or in the spaces of loose tissue under the arms, in the fold of the thigh, and, in entire horses, in the testicles.

During the course of the disease, or later, when the animal seems to be on the road to perfect recovery, abscesses may form in the internal organs and produce symptoms characteristic of disease of those parts.

Roaring, plunging, wandering in a circle, or standing with the head wedged in a corner of the stall indicate the collection of matter in the brain. Sudden and severe lung symptoms, without previous discharge, point to an abscess between the lungs, in the mediastinum; colic, which is often continuous for days, is the result of the formation of an abscess in some part of the abdominal cavity, usually in the mesentery.

Pathology.—The lesions of strangles are found on the surface of the mucous membranes, essentially of the respiratory system, and in the loose connective tissue fibers of the internal organs and glands, and consist of acute inflammatory changes, tending to the formation of matter. The blood is unaltered, though it is rich in fibrin, and if the animal has died of asphyxia it is found dark colored and uncoagulated when the body is first opened. If the animal has died while suffering from high fever the ordinary alterations throughout the body, which are produced by any fever not attended by alteration of blood, are found.

Prevention.—Healthy horses should be separated from the infected animals, and the stables in which the disease has occurred should be thoroughly disinfected. Since the disease frequently occurs annually on infected premises, systematic disinfection should be practiced after an outbreak. The stables, as well as all utensils which might have come in contact with the infection, should be thoroughly disinfected. By such practices recurrences of the disease may be prevented.

Treatment.—Ordinary light cases require but little treatment beyond diet, warm washes, moistened hay, warm coverings, and protection from exposure to cold. The latter is urgently called for, as lung complications, severe bronchitis, and laryngitis are often the results of neglect of this precaution. If the fever is excessive, the horse may receive small quantities of Glauber's salt (handful three times a day) as a laxative, bicarbonate of soda or niter in one-dram doses every few hours, and small doses of antimony, iodid of potash, aconite, or quinin. Steaming the head with the vapor of warm water poured over a bucket of bran and hay, in which belladonna leaves or tar have been placed, will allay the inflammation of the mucous membranes and greatly ease the cough.