Part 29

Virulent Products. Infection is present sooner or later in all the morbid animal products. The nasal mucus, bronchial exudate, saliva, tears, contents of the cutaneous vesicle, milk, contents of the bowels, and the blood have been successfully inoculated on susceptible subjects. Inoculations with blood failed with Bryce, but proved successful with Konnhauser, Krajewski, Even, Lignieres and Physalix, so that the first named cases may be explained by a prior immunity, or by a too advanced stage of the case which furnished the matter. The virulence is not lost nor even diminished by drying at ordinary temperatures, freezing (10° F.), nor by moderate dilution in water. Prolonged exposure at ordinary temperature, however, reduces the virulence, which is greatly impaired in 15 to 25 days (Laosson), or, if dried, in three months and upward (Krajewski). Virulence is easily destroyed by disinfectants,—thorough washing (Menard) hypochlorous acid (Trasbot), chloride of lime, mercuric chloride, etc.

Forms of Distemper. This disease is extremely protean in its manifestations. Many cases, in country districts especially, are manifested by a slight fever, with a catarrhal condition of the mucosæ of the nose, eyes, and throat. In other cases there may be simply a slight conjunctivitis or keratitis, and in still others a cutaneous eruption, papular, vesicular or pastular. In some instances there is slight gastric or hepatic disorder with inappetence nausea, and vomiting or some irregularity of the bowels. In such cases recovery may take place in eight or ten days.

In the more severe forms, especially seen in house and city dogs, and in high bred and confined dogs generally, the fever is high and persistent and the disorders often predominate in particular organs, hence we see a catarrhal form, a conjunctival, a bronchitic, a pulmonary, a gastro-intestinal and hepatic, a cutaneous and a nervous. The severe cases may last for twenty or thirty days or even in their sequelæ for several months. Exposure to cold contributes greatly to a pulmonary attack even in inoculated cases (Lignieres).

The mortality varies greatly. In country dogs it may be below 20 per cent., whereas in city dogs and those kept confined in close quarters and in large numbers it may rise to 50, 60 or even 70 per cent.

Prognosis is especially unfavorable in severe cases; in those profoundly affecting the brain, lungs or liver; in high bred or pampered dogs; in the very young; in the debilitated, anæmic or rhachitic; in those that have been recently imported from another climate and are as yet unacclimated. Puppies from debilitated dams, or those raised in a large litter with insufficient nourishment, or older dogs confined to a purely vegetable diet show less power of recuperation. Profound prostration and offensive odor, from excess of toxins are always to be dreaded.

Incubation in inoculated cases varies from four to seven days (Krajewski). When contracted by simple exposure it may seem to have been extended to fourteen or even eighteen days.

Symptoms. The earliest symptom is hyperthermia (103° to 104° F.) This is accompanied and followed by prostration, dulness, impaired appetite, erection of the hairs along the spine, shivering, trembling, seeking a warm place, fatigue on slight exertion, hot dry nose, burning pads of the feet, sometimes taciturnity. Later the temperature may descend even to the normal or there may be alternations of rise and fall. One of the most characteristic symptoms of distemper is the implication of more than one set of organs, so that morbid manifestations referable to the nose, eyes, throat, stomach, skin and nervous system occurring in the same subject are to be especially noted. In enumerating the prominent symptoms caused by disease of one set of organs therefore, it is not to be implied that the absence of others referring to a different class of organs is to be understood. On the contrary a complication of several is especially significant of this disease, though the predominance in one class of organ will signify a special form of the disease.

Respiratory Symptoms. One of the earliest symptoms is usually sneezing with redness of the nasal mucosa, followed by a muco-purulent blocking of the nose, and rubbing of it with the paws. With the implication of the throat there is usually local tenderness and a hard, painful cough, which may be accompanied by retching or vomiting. The breathing becomes snuffling, especially in pugs and bull dogs, and rapid and even oppressed in case of implication of the smaller bronchia and lungs. The nostrils may become glued together, the discharge red or dark in color, vesicles and sores may appear on the mucosa, and the cough gets paroxysmal, small, weak and husky or gurgling.

Percussion of the lungs may reveal small areas of flatness from exudate or collapse, and in case of pleurisy and hydrothorax there is a lack of resonance up to a given horizontal line, varying in position according to the position of the animal and always keeping to that part of the thorax which may at the time be lowest. Auscultation will reveal various sounds according to existing lesions. There may be a loud blowing murmur over the large bronchia, or at points to which this sound is conveyed through consolidated lung. Or a coarse or fine mucous râle may be present indicating the second stage of bronchitis, or a line of crepitation, around a non-resonant area indicating pneumonia, or there may be friction sounds or, later, creaking murmurs from false membranes. Wheezing and sibilant sounds are not uncommon, also sounds of the heart, bronchia or bowels, heard in unwonted situations to which they are conveyed through consolidated lung tissue. Dyspnœa may become extreme, with puffing out of the cheeks, labial soufle, and violent inspiratory action. Fœtor of the breath is common. Emaciation, marasmus, sunken, pale or dark red eyes, putrid diarrhœa and nervous disorders usually precede death.

Eye Symptoms. Conjunctival congestion is one of the earliest and most constant symptoms. Weeping, swollen eyelids and red turgid mucosa. Photophobia may bespeak keratitis. Soon the watery tears become muco-purulent, matting together the lashes and even the lids, during the night especially, so that they must be sponged to get them apart in the morning. The exudate may accumulate under the lower lid, or may become flocculent, and usually flows down the cheeks causing matting and even shedding of the hair. Vesicles exceptionally appear on the conjunctiva; more frequently it becomes cloudy and opaque, and at points near the centre, degeneration of the epithelium leads to the formation of ulcers no larger than pinheads, but extending into the cornea and sometimes perforating it so as to allow protrusion of the membrane of Descemet or the escape of the aqueous humor. The formation and extension of the ulcers are favored by the general debility, the rubbing of the eye with the paws, and the infection of abrasions, by pus microbes. This infection may extend to the lining member of the anterior chamber and even of the posterior with panophthalmia, but, in the absence of perforation, internal ophthalmia is rare. When the ulcers heal, white cicatricial spots, or black points caused by the adhesion of the uveal pigment remain.

Digestive and Hepatic Symptoms. Anorexia and vomiting may usher in the disease. Buccal congestion, dryness, clamminess and fœtor are marked symptoms and there may be some yellowness of the mouth and eye. The patient is at first costive, but diarrhœa often sets in early, with tenesmus, much fœtor, mucus, froth and even blood, also abdominal pain and tenderness. The abdomen is habitually tense and contracted. The alvine flux may rapidly exhaust the animal, or it may continue for a month in dysenteric form with intense fœtor, weakness, emaciation and exhaustion. Ulceration of the mouth, gums and rectum, invagination, prolapsus ani, jaundice, septic pneumonia, paralysis, chorea, convulsions, or cutaneous eruptions are occasional complications. The abdominal type of distemper is especially fatal. Even in its early stages debility, prostration and even drowsiness are marked features.

Cutaneous Symptoms. Skin eruptions are observed in the great majority of cases, at some stage of the disease, and may remain as a sequel for a time after apparent recovery. Friedberger and Fröhner note cases in which the high fever and skin eruption are the only prominent symptoms, and recovery may be looked for with some confidence. The lesions are most patent on white skinned dogs with short hair, and on the more delicate parts of the skin (abdomen, scrotum, perineum, inside of the thighs and elbows) but they may extend over the whole body and even extend on the mucosæ. They vary much in different cases and stages. There may be punctiform reddish spots, changing to hard elevated papules, and, in the case of a certain number, to vesicles and even pustules. Some vesicles may be small and pointed, but more commonly they are rounded and flat, and as large as a lentil or small pea. When first formed, the contained liquid exudate may be clear and transparent, but often it is reddish or even violet. The individual vesicles tend to speedily burst, and dry up, but others appear, and thus the eruption will continue for weeks, the skin meanwhile exuding a sticky, greasy, offensively smelling exudate which mats the hairs together. Itching is usually slight, yet in given cases excoriations and sores are produced with considerable moist discharge. It tends to spontaneous recovery when the general health improves and appears to be little affected by local treatment.

Nervous symptoms. These are shown more or less from the beginning. The great dulness, depression, apathy and weakness, which usually usher in the disease, are indications of this. Drowsiness may be early shown. Even the early nausea and vomiting may be largely central in its origin. In some cases, however, the brain symptoms are more active and violent. The dog is restless and irritable, getting up and moving from place to place, starting from sleep, yelping, snapping, with twitching of the muscles of the face or limbs, rolling of the eyes, and excessive heat of the head. Krajewski even describes rabiform paroxysms, depraved appetite, spasms, furious delirium, fawning, or threatening, and finally paraplegia and maxillary paralysis Occurring in a country where rabies is familiar it would have been more satisfactory if inoculations had been made from such cases with results negativing rabies. Epileptic attacks may appear at any stage of the disease. Chorea, tonic spasms, paresis and paralysis are on the contrary habitually late manifestations and often seem to be sequelæ determined by toxin poisoning of the nerve centers, or degenerations of their structure. Choreic movements may be confined to the head, or a limb, or they may affect the whole body. Tonic spasms often affect the neck, turning the head rigidly to one side. Among other nervous disorders may be named, amaurosis with dilated pupil and atrophy of the optic nerve, deafness, anosmia, and dementia.

Lesions. These vary as do the symptoms. The nasal pharyngeal, and laryngeal mucosæ show congestion, swelling, infiltration, ecchymosis with vesicles, pustules and ulcerations. They are covered by a foul muco-purulent exudate. The same condition may often be traced to the final ramifications of the bronchial system. In pulmonary cases, the lungs show inflammation, inflammatory exudation and consolidation, collapse, splenization, œdema, and even suppuration in points or large areas. The bronchial lymph glands and often the pharyngeal are enlarged, congested and may be suppurating. The pleura over the congested lung may be the seat of exudation and false membrane, and a bloody serum may occupy the pleural cavity. The heart may show parenchymatous degeneration.

In the digestive organs there may be buccal congestion, with degeneration and the desquamation of the epithelium and formation of more or less extended ulceration. The stomach shows similar congestions and degenerations, the ulcer appearing particularly on the summit of the folds. Together with the intestines this often presents numerous petechiæ and ulcerations, and is covered by a foul but often tenacious mucus. The agminated and solitary glands are usually swollen and infiltrated, and the mesenteric glands are swollen, congested and infiltrated.

The kidneys are often congested, and show points of blood extravasation and tissue degeneration.

The meninges of the brain and cord are often inflamed with infiltrations, false membranes, and especially exudation into the subarachnoid and ventricles. Centres of congestion and softening have been noted in the brain and cord with embolism of capillaries and softening and degeneration of their endothelium. Nocard and others have noted a leucocytic infiltration of the perivascular lymph spaces. In old standing cases sclerosis is an occasional feature.

In nearly all cases there is marked emaciation and a very heavy offensive odor comes from the skin, the tissues, the contents of the bowels and the exudates on the respiratory passages.

Lignieres alleges that in the early stages, the specific bacillus is found in the blood and viscera, but that later it is only exceptionally found and that other bacteria (streptococcus, etc.,) usually take its place. In the nasal discharge it may be found at times, but in the more tardily appearing cutaneous vesicles its absence is the rule, and in the brain matter and meningeal and ventricular fluids, in cases of paralysis or chorea, it is not to be detected by culture. Hence the case cannot always be diagnosed by a successful search for, or culture of the germ, and hence also the frequently unsuccessful inoculations with the blood, tears, liquid of vesicles, and even the lung tissues or nasal discharges.

Prevention. Distemper, like any other contagious malady may be excluded from a city or district by the simple expedient of shutting out animals that bear the infection. From a kennel or pack of hounds, new arrivals should be quarantined for a fortnight, until danger is past, and should only be admitted after a good soapy wash. All clothing, collars, brushes and other material that came with them should be thoroughly disinfected. Dog shows and other meetings are to be avoided as far as possible, and any animal that has returned from one should be quarantined and all his belongings purified. Dogs that run at large should be carefully excluded from kennels where valuable dogs are kept, and from all possible contact with them. Even mice, rats, and birds have to be considered if the disease exists in the near vicinity. When the disease exists in a district a sound sanitation would demand the shutting up of all dogs on their owner’s premises, unless carefully led on chain and prevented from coming in contact with other dogs.

When the disease has broken out in a pack of hounds, or a populous kennel, the dogs should be separated into small lots of 3 or 4; the temperatures of all should be taken twice a day; any lot in which one shows a high temperature should be instantly removed to a safe distance and placed in quarantine; and the enclosure where they have been and all their belongings should be thoroughly disinfected. The enclosures where the sick are kept must be carefully quarantined so that no infection may escape on food, water, brushes, utensils, clothing, attendants, cats, vermin, or even birds.

The dogs that are still healthy should have spacious, well-aired dwellings, open air exercise (as much as possible in the fine season), good but not too stimulating food (in part at least fresh animal food), pure water, and protection against undue fatigue, cold, icy baths, especially when exhausted, rain or snow storms and cold stone or metallic beds. In the cold season artificial heat in the kennel is desirable.

Immunization may be sought in various ways based on the use of the toxins and antitoxins on the one hand, and of a weakened type of virus on the other. Bryce (1882) and others inoculated with the blood and pulmonary exudate, and produced in three-months-puppies, local swellings mainly, with subsequent immunity. The mortality from the inoculation did not exceed 10 to 15 per cent. These losses imply that in certain cases the material inoculated conveyed the microbe of the disease, and the survivors acquired all that immunity which comes from a first attack. In the cases that show local lesions only, it may be presumed that few microbes or none were inserted, while the results came mainly from the toxins or antitoxins. This would be entirely in keeping with Lignieres’ observation that the blood and pulmonary lesions often failed to furnish the pathogenic microbe, as tested even by attempts at artificial cultures. The protection secured from the antitoxins alone is shortlived, terminating with the elimination of these elements, while that coming from the action of the toxins on the leucocytes, and the stimulation by these to the production of defensive products, is much more lasting and in ratio with the quantity of the stimulus introduced and the profundity and duration of its influence on the leucocytes. This may partly explain the occasional early exhaustion of the immunity and the reinfection of the animal within a year after inoculation.

Physalix working in Chauveau’s laboratory has found the best results from the use of weakened artificial cultures. He cultivated the microbe of Lignieres in peptonised bouillon having 6 per cent. of glycerine, and allowed successive cultures to rest (without reseeding a new culture fluid), after they have attained to their full growth. The strength of the culture is in inverse ratio to the period that elapsed between successive cultures, leading up to this one, and the first inoculation is made with the weakest product that will produce a very limited local swelling which is fully developed in 48 hours, and disappears in a few days. Three or four inoculations are made successively with cultures of gradually encreasing potency, after which immunity persists for years. It is to be understood, that an overdose will overcome the immunity at any time; also that the passage of a culture of lessened potency through a dog or Guinea pig will raise it to its original virulence. Physalix operated only on young dogs, that had not shed their milk teeth, and injected 2 to 3 c.c. of the culture as a dose with only 2.5% mortality. Others had less success.

Treatment. To secure good results in the treatment of distemper every attention must be paid to good hygiene. An open air life in summer, and a roomy, clean, well-aired, warmed building in winter are most important. Chills, foul air, and filth generally are to be carefully guarded against. Food should be moderate in amount, easily digested and nutritious. Milk is especially good (sweet, skim or buttermilk); then biscuit and milk, or in patients accustomed to animal food, lean meat, minced, scraped or pulped. Warm baths are often advantageous, but they must be given with great caution to avoid chill.

Medicinal treatment is largely symptomatic. An excessively high temperature (104° and upward) may be met by warm baths, or antipyretics—quinine, acetanilid, salicylate of soda, antipyrine, phenacetin, or even damp compresses to the sides. As a rule, however, it is not well to continue such agents as acetanilid, antipyrine or phenacetin longer than is absolutely needful to reduce excessive temperature.

Attempts have been made to check microbian proliferation by antiferments, such as quinine, calomel, creolin, phenol, and phenacetin. The tonic action of quinine specially recommends it but like all bitters it is obnoxious to a dog with a delicate stomach. Calomel is especially recommended by Fröhner as a gastric and intestinal antiseptic and its indirect action on the liver renders it valuable in many cases. Creolin and carbolic acid exhaled from saturated cloths tend to disinfect the air passages and give tone to the mucosa. My colleague Dr. P. A. Fish gave carbolic acid, 2 per cent., and afterward 4 per cent. in normal salt solution, and in doses of ½ to 1 drachm, subcutem once and twice a day. In the initial stages, it seemed often to be of great value, quieting the nervous excitement, improving the general symptoms, and in some instances apparently cutting short the affection. Trasbot recommended strong infusion of coffee, and Zippelius sodium chloride, while others gave ergotin, or better hydrogen peroxide in spray or as a draught.

Eliminative treatment. As in all depressing contagious diseases, we must favor elimination of the toxins, and in this case without risking any material encrease of debility. Calomel (7 grs.), sodium salicylate or benzoate (4 grs.), sodium bicarbonate (7 grs.), potassium iodide (4 grs.), chlorate (7 grs.), or nitrate (7 grs.) may be cited. Digitalis (1 gr.), strophanthus, or caffeine are especially recommended by their power of encreasing the tone of the heart when that has become weak or exhausted.