Part 18

Symptoms. These vary greatly in different cases, mild and severe. Some, in the same stable with the severe cases, simply refuse food, are a little sluggish in work, cough, have hyperthermia (104° to 106° F.), respirations 20–25, pulse 60, with conjunctiva only moderately yellow, a slightly yellowish discharge from the nose, and no observable lung consolidation. The temperature descends to normal in three to five days, the symptoms generally abate, and the animal may be convalescent in eight or ten days.

In the more severe cases there may be seen a shivering fit, or it may pass unobserved. Then the first morbid phenomenon is usually a rapid and extreme elevation of temperature which may reach 104° or 106° F. in a few hours. With this there is great impairment or complete loss of appetite, and a loss of life and energy. In some cases the depression, stupor and muscular weakness suggest influenza but this is not the rule. Still more rare is infiltration of the eyelids and free watering of the eyes, yet in the absence of this, drooping of the upper eyelids is not uncommon. The respiration may be accelerated and short, from 20 to 30 per minute, and the pulse, which is usually small and weak in spite of the fever, may rise to 50 or 70 per minute. The breathing may be trembling or distinctly interrupted in the course of inhalation or exhalation, short and with no interval between inspiration and expiration. Cough may or may not be a marked feature, heard at long intervals only in some cases and frequent and painful in others. It is liable to be dry and husky rather than hard, loose or gurgling. The eye and to a less extent the nasal and buccal mucosa tend to show a yellowish shade, and this may even at an early stage show a distinct brownish orange, or even a dark mahogany hue. Yet dropsy of the lids or even epiphora are uncommon. A yellowish discharge from the nose is an almost constant feature and this may dry up into a yellow crust on the floor of the anterior nares and adjacent skin. The percussion and auscultatory indications of lung consolidation are rarely obtainable before the end of the second or third day and when at all extensive can usually be detected on both sides. Trasbot considers the double pneumonia as almost pathognomonic of contagious pneumonia. When confined mainly to the lower parts of the lungs and occurring in isolated areas, with lung tissue still pervious to air in the intervals, it comes more nearly to being so. Crepitation round the border of consolidated areas, is a more marked feature than in equal consolidations in influenza. It often becomes inaudible again as the disease advances. Blowing murmurs, coarse mucous râles, heart and intestinal sounds can often be heard with unusual clearness, in unusual situations, when an area of consolidated lung is immediately beneath. A transient dry friction sound of commencing pleurisy is sometimes detected over a tender intercostal area, but soon giving place to the uniform quiet of effusion rising to a given horizontal level. Later still there may be the creaking sound of organizing false membranes in process of being stretched, and which is so often confounded with crepitation. The indications of pneumothorax (tympanitic resonance, and metallic tinkling), are rare. In advanced stages there may be tympanitic sound from the cavities of abscesses or the sacs containing sequestra.

The urine is always scanty and high colored and may at times prove red and hæmorrhagic. Albuminuria is usually present when the disease is at its height. The same is true of uric acid, which replaces the hippuric acid, in cases of high fever and complete abstinence so that the products are drawn from the disintegrating tissues alone. The returning appetite, and the restoration of a neutral or alkaline condition of the urine, therefore tend to occur simultaneously, and to mark improvement.

Great tenderness of the throat, protrusion of the nose, and difficulty of swallowing mark the localization of the lesions on the pharynx and larynx. It is liable to be accompanied by the introduction of exudation and food materials into the larynx and trachea with the occurrence of inhalation bronchitis and pulmonary gangrene.

Symptoms of pericarditis, endocarditis and myocarditis, are especially common in the more severe types of the disease. With soft, weak or imperceptible pulse and tumultuous heart beats they may be suspected, and further indications are a transient friction sound, synchronous with the beat of the heart, intermissions, murmurs with first or second heart sound, and an increasingly low, distant, or muffled heart beat, as pericardial fluid accumulates. As in the case of troubles with the kidneys or liver, stocking of the legs, or dropsical swellings elsewhere may appear.

Exceptionally, acute nervous symptoms may appear, due to functional derangements caused by circulation of the toxins and metabolic products, or even to congestion or inflammation of the brain or its membranes. This may occur at the outset of the disease indicating the election of the nerve centres for the colonization of the microbe, and advancing to a rapidly fatal issue (Friedberger and Fröhner). It may set in with hepatization (Rey), or it may coincide with pulmonary gangrene (Cadeac). There may be merely dulness, prostration, or stupor; or trembling, unsteady gait, or falling; there may be rolling of the eyes, or amaurosis, or vertigo occurring intermittently; or there may be epileptic attacks or paraplegia.

Course. In moderate cases the disease may last from two to three weeks, and in well conditioned horses, with strong constitutions, tends to recovery. On the third to the eighth day all the symptoms appear better, appetite, expression, alertness, breathing, pulsation and temperature. The temperature which has been a degree, or more, higher in the afternoon than in the morning, remains about the same from morning to night, or is even slightly lowered; it is lower still next morning and in two or three days may have reached 101°, still rising a little in the afternoon. The pulmonary exudate is usually quickly absorbed though less so than in favorable cases of influenza. Convalescence may be completed by the end of the third or fourth week.

In violent and fatal cases the general symptoms tend to encrease in violence, though the temperature may descend to 103°, and in the final collapse to 100° or lower. In a mare presented at the college clinic after three weeks illness and treatment elsewhere, prostration was extreme, the head rested in the manger, the nose discharged a fetid, glairy, frothy liquid, with grumous, bloody debris; breath offensive; pulse 92, almost imperceptible; respirations 30, very labored; nostrils widely dilated, flapping; temperature in vagina 103.6°, anus was open with constant ingress and egress of air, and a watery glairy, frothy discharge; extensive dropsy under the sternum; percussion and auscultation indicated consolidation of lungs from the lower border up, crepitation, creaking, and loud clucking bronchial sound. The mare survived for forty-eight hours, the temperature descending to 100.5° in the morning and rising to 102° and upward in the afternoon. At the necropsy the right lung was consolidated throughout, the left had pervious areas anteriorly and posteriorly; there were large areas of infarction, necrosis, with encystment, caseation, and lobular and perilobular exudation and hepatization.

Liver, enlarged, tense in its capsule, but soft and friable on its cut surface, with areas of softening and necrosis. Both kidneys congested, with pale zones of necrosis; right enlarged. Beside the substernal exudate, there was extensive hæmorrhagic exudate between the serratus magnus and ribs. The blood, very dark, brightened on exposure to air.

Diagnosis: This may be based mainly on the prevalence of the disease in the district, or the fact that the victim has come from a long railway journey with risks of exposure, or has stood by a horse just arrived; on the prompt loss of appetite and sudden and extreme rise of temperature, without notable lung lesions; on the deep brownish yellow discoloration of the visible mucosæ, especially that of the eye, and on the yellow discharge from the nose, the tardiness with which successive cases follow each other comparatively to influenza, and the absence in large measure of the early extreme prostration of that affection. (See table under influenza).

Prognosis varies with the progress of an epizoötic, and the youth and susceptibility of the animal together with the favorable or unfavorable conditions of life. The death rate is usually high at the outset when the more susceptible animals are attacked, and for the same reason, in the young that have not been previously exposed. Old and debilitated animals with broken down constitutions suffer severely, and bad hygiene contributes much to the mortality. The deaths vary from one to twenty per cent. But short of death, permanent injury follows in a number of cases. Encysted sequestra remain in the lungs for months and when liquefied and absorbed, leave fibroid masses in place of healthy lung tissue. The fibrous organization of peribronchial exudates, impairs respiration, and the same is true of the fibrous development of false membrane. Thus the horse is left permanently broken-winded or short-winded, or from interference with the recurrent laryngeal nerve, laryngeal hemiplegia (roaring) ensues. In still other cases permanent adhesions of the pericardium, or insufficiency of the cardiac valves, or disease and distortion of joints or tendons, or nervous, hepatic or renal degenerations destroy or seriously impair the value.

Treatment. Hygienic measures are of prime importance in treatment. A dry, clean box stall with pure air, and genial warmth (60°–70° F.)—in warm summer weather outdoor air—must be secured. In cold weather a sunny outlook, and clothing—blanket, bandages, and it may be a hood—to counteract any sensation of chill. Tepid drinks, pure water changed often, linseed tea, barley water, are of importance in allaying thirst, lowering temperature and favoring elimination. Absolute rest is all essential. Keeping at work after the onset of the disease is nearly equivalent to signing the patient’s death warrant.

The high temperature at the outset of the disease seems to demand antipyretics, and in times past, in Southern Europe especially, bleeding was a constant resort. But even under favorable conditions this does not lower the temperature more than 1.5° F., and the resulting debility is such that it has been long discarded in Germany, England and America. In cases of acute extensive pulmonary congestion it is helpful in relieving the vascular tension on the lungs and allowing the tissues to better reassert their natural functions, in antagonism with invading microbes and their poisons, but even this action is transient, and when it saves life it is probably only by tiding over safely a very transient and urgent danger.

The same decline of temperature can usually be secured by injections of cool water into the rectum, and with the added advantage that this relaxes the bowels, and removes dried irritant masses from the rectum and floating colon.

As in other pneumonias the application of cold to the skin is liable to bring on a chill unless the temperature is very high. A safer and hardly less effective method is to apply around the chest a thin blanket or sheet wrung out of tepid water and cover it closely with dry blankets holding these close to the skin by elastic circingles. No part of the damp compress must be allowed to remain exposed to the air under pain of causing chill. Damp cotton wool applied next the skin tends to maintain its contact by its own elasticity, so that it requires less care in the elastic dry covering. This moist warmth draws a free circulation of blood to the skin, so that it is cooled and sent back internally to cool the burning fever, without sensation of chill. The abstraction of this large mass of blood to the skin, acts like bleeding in diminishing the blood tension in the chest and allowing the resumption of the normal vaso-motor and nutritive functions without the dangers of venesection. The soothing action on the skin, soothes by sympathy the infected and inflamed tissues.

A steam or hot air bath may serve a similar purpose. Conjoined with an aloetic laxative and aconite, I have seen this reduce the temperature from 104.5° F. to 102.7° F. at the next taking 18 hours later. It only once again reached 103° F. in the subsequent course of the disease.

To secure diaphoresis, warm mashes or gruels may be freely used. Alcoholic drinks have been freely used (the weaker wines 1 to 2 qts., sherry, brandy, whisky ½ to 1 pint), camphorated spirit (2–3 drs.) subcutem, ipecacuan (1 oz.), tartar emetic (2 drs.), liquor of acetate of ammonia (4 ozs.), pilocarpin (2 grs. subcutem). If the alcoholic liquors produce a free circulation and glow in the skin, better still if diaphoresis, they are useful antithermics, but, if they fail in this, they may do harm by reducing the vital activities of the leucocytes, and their power of resistance. Trasbot has had uniformly unfortunate results with alcohol in large doses. The same objection attaches to tartar emetic and other depressant diaphoretics, though valuable if free diaphoresis is secured.

Constipation may be met by cold water injections, calomel (½ to 1 dr.), pilocarpin (3 grs.), eserine (1½ gr.), sodium sulphate or other agent graduated to requirement.

An expectorant and alkaline diuretic action may be obtained from potassium iodide (1–2 drs.), ammonium chloride (2 drs.), or ammonium acetate. These not only liquefy the exudate, and facilitate expectoration, but secure elimination of toxins, ptomaines and waste products from the blood and system. The iodide is besides somewhat antiseptic.

In the early stages especially medicinal antithermic agents may be called for: acetanilid (2–3 drs.), phenacetin (2–4 drs.), sulphate of thallin (2–3 drs.), sodium salicylate (½ oz.) or in the weaker cases, caffein—natrium salicylate (1 dr.) or quinine sulphate (2–3 drs.) Acetanilid will sometimes relieve dullness, and materially improve the general condition.

In weak conditions of the heart we may resort to digitalis (10–15 grs.), strychnia sulphate (2 grs.), strophanthus tincture (3 to 4 drs.), caffein, or alcohol. Care must be taken not to overstimulate and exhaust a weak and intermittent heart.

Derivatives are often of material value from the first, in mild cases or to succeed damp compresses in the more violent ones. One of the best and most convenient is essential oil of mustard and alcohol (1:12 or 20). This may be rubbed on the surface and like mustard itself, covered with stout paper to prevent evaporation. In the absence of this, soap liniment, or even tincture of cantharides may be used.

The use of antiseptics has been tried with variable results. While it is impracticable to saturate the system, safely, with sufficient antiseptic to destroy the microbes in the blood and tissues, yet when the balance of force between the microbian attack and systemic defence shows little variation either way a slight increase on the side of the patient may serve to give it the preponderance, and to restrict the increase of the microbes and their products. Above all when the center of morbid activity is largely on and near the bronchial mucosa, antiseptic inhalations serve to hold them somewhat in check and to moderate the amount of both microbes and toxins that enter the system at this point. For this purpose camphor, oil of turpentine, or oil of tar volatilized from hot water may be inhaled in a close room. Or we may use carbolic acid, terpene, terpinol, creolin lysol, thymol, eucalyptol, or oil of cinnamon. The fumes of burning sulphur diffused in the air of the room and just short of that concentration that will cause cough, suffering and headache, is an excellent resort. The sulphites, bisulphites or hyposulphites may be given by the mouth.

When there are indications of encephalitis cold to the head and the internal exhibition of bromides, iodides, and acetanilid may be resorted to.

During convalescence nourishing and easily digestible food may be given, and iron, strychnia, quinia and common salt may be employed. In protracted or chronic cases with fœtid breath and indications of sequestra or opened vomica in the lungs these may be continued along with one or more of the disinfectants referred to above.

Prevention. This is much more promising than in equine influenza. The extension of incubation to three days and the indisposition of the infection to spread beyond the stable into which it has been brought, or the near vicinity of the diseased animal, gives us a great relative advantage. The early, extreme rise of temperature of the infected horses gives the opportunity of removing these horses to a special stable or shed, where they can have special attendants, and the stable drainage and manure can be kept apart, and disinfected, or spread and plowed under by oxen. The infected stable should be emptied, the soiled hay, litter and manure burned, and the walls, partitions, floors, ceilings, and above all the mangers and racks must be thoroughly disinfected. Lime wash with chloride of lime or mercuric chloride will suffice. The gutters should be cleaned, washed and drenched with mercuric chloride, followed by the whitewash. If there is rotten wood work or filth-saturated soil these must be effectually treated. In many stables it will be impossible to do all this thoroughly, yet closing the empty building tightly, and filling it with chlorine gas, or even sulphur fumes, concentrated until they extinguish the burning sulphur, and keeping shut up for twenty-four hours will usually suffice. Washing with a solution of formalin (1:40 or 1 per cent of formaldehyde), or even the evaporation of this agent by heat in the closed building is very effective, with the serious drawback that it is very irritating to the lungs. It can however be conveniently used for the sterilization of harness, stable implements, halters, and all movable objects in the building.

Strange horses, such as new purchases, should be placed in quarantine for one week in a separate stable, and not hitched up with sound horses. If they show evidence of recent illness this may be extended to six weeks.

For horses that have been shipped long distances, and stopped for rest or feeding in public stables or yards, a similar quarantine is essential. This might be obviated if a system of thorough disinfection of such stables, yards and cars, could be enforced, between any two successive lots of horses, and if the latter were accompanied by certificates of the absence of contagious pneumonia and all other infectious diseases from the localities from which they were shipped and through which they had come. Such certificates should be made by veterinary officials in the employ of the government, which would thus become responsible for their genuineness.