Text book of veterinary medicine, Volume 4 (of 5)

by James Law

Diagnosis. The early diagnosis of rabies in the dog is of supreme importance as enabling the owner to destroy or seclude the dangerous animal before he has developed the disposition to bite and to propagate the disease. If the dog himself is known to have been bitten, every premonitory symptom should be carefully looked for and critically studied. Any change in the general habit, unusual liveliness or dulness, restlessness, or somnolence, unwonted affection or taciturnity, special watchfulness with vision, or hearing, change in the character or tones of the voice or the disposition to use it, propensity to swallow foreign nonalimentary bodies, retching, vomiting or costiveness, propensity to hide away in a dark corner or to leave home and disappear for a day or more, disposition to gnaw and tear up wood or clothing, or hyperæsthesia affecting any of the senses should be carefully noted. Note especially any exaggeration of the generative instinct, any strabismus, or redness of the eyes, any turning of the eyes or head after imaginary objects or snapping at them, any disposition to anger or attack when another dog or cat is presented and any disposition to growl at or to bite a stranger. This tendency to anger and resentment though not always present is usually a symptom of the very greatest value. If a dog is known to have bitten or attempted to bite any person or animal he should be tied or shut up in a safe place for four days at least, under veterinary supervision, and set free only on condition that no symptoms have developed at the end of this period. A hasty decision that a suspected dog is not rabid must lay a veterinarian open to the most serious charges, in case rabies occurs in man or beast from the bites.

Diagnosis is less difficult after the paroxysmal stage has set in. Then there is the extreme irritability and hyperæsthesia, the appearance of reflex spasms of the pharyngeal muscles and chest under the influence of any peripheral excitement, the derangement of the senses, the dilated pupil, the flashing eye, the squinting, the taciturnity and the propensity to bite. Later still the lack of coördination of movement or the paralysis, especially of the hind limbs and of the jaws.

The symptoms may be simulated by those of some other diseases. Thus the bitch which has been exhausted by lactation may show delirium with taciturnity and a disposition to snap. The dog, which is habitually struck or threatened by passers by, may acquire a sinister look and a disposition to bite on every occasion. The presence of a bone or other foreign body fixed between the upper molars, and various injuries of the jaws, teeth or throat may cause inability to swallow, change of the voice and a morose disposition and expression. In such cases there may be vomiting, rubbing the jaws with the paws as if to disengage something and salivation, but there is neither delirium, fury, muscular weakness nor paralysis. In paralytic rabies on the other hand, along with the open mouth and drivelling saliva, there is no disposition to paw the mouth nor face, the buccal mucosa is not simply red but of a deep violet, and there is attendant weakness or paralysis of the hind parts.

Galtier has seen inability to swallow and dropping of the lower jaw from violent stomato-pharyngitis, and from dislocation of the maxilla.

Great tenderness of the skin from inflammation due to blistering or caustic agents or from rheumatism may cause such alert apprehension and disposition to bite in self defense that it may simulate hyperæsthesia of rabies.

From pharyngeal anthrax and violent angina, rabies is distinguished by the extreme exaltation of the special senses, the marked hyperæsthesia and reflex excitability, and, as in the other diseases mentioned, by the perfectly lucid intermissions. Epilepsy is not to be roused by sudden noise, movement nor attempts to swallow, it is not associated with hyperæsthesia and in the haut mal the spasms affect the muscular system more generally. A disposition to bite, and spasms and other nervous symptoms, resembling to some extent those of rabies, have been seen in cases of pentastoma in the nasal sinuses, cysticercas in the brain, filaria immitis in the blood, nematodes, and tænia in the bowels, and auricular acariasis, but there is no such hallucination nor visual delusion, no alteration of the voice, no cutaneous anæsthesia, no exalted reflex excitability. Cadeac finds rabiform symptoms with disorders of the special senses in animals dosed with various essential oils, but the odor of these essences about the mouth and in the breath would serve to distinguish.

Symptoms in Cats. The disease makes a rapid progress, and often ends in death in three or four days. There is a marked change of voice, the calls being hoarse and bass, having been compared to that of a cat in heat. As in the dog, there is a disposition to pick up and swallow objects that are in no sense food, perhaps even its own urine or fæces. There is a great tendency to hide away under furniture or in secluded corners so that the malady may be far advanced before anything is suspected. If seen the patient shows restlessness and frequent movement, with a marked excitability under noise or other disturbing influence. Any disturbance may arouse a paroxysm, accompanied by occasional wide dilatation of the pupils, with flashes from the bright carpet in the vitreous chamber, and the patient may spring at human beings and bite or scratch the hands, face or other uncovered portion of the body. It shows the same disposition to bite small animals, and especially dogs. A glairy often frothy saliva is found in the mouth and often around the lips. As the disease advances and paresis sets in, the cat usually crawls into some dark secluded corner and there dies.

Symptoms in Solipeds. These may vary much in different cases but the leading characteristics, as seen in the dog, are prominent also in the soliped. There is marked restlessness, trembling, and extraordinary hyperæsthesia, as seen in starting at sounds, sudden flashes of light or other causes of disturbance. The ears are held erect and watchful for sounds; the eyes are red and mostly vigilant with at times pupillary dilatation and flashing. The sight of a dog rouses him instantly to attack it with teeth and heels. A stranger is liable to be similarly treated though the horse is still docile and kind to his keeper. There may be itching of the skin and above all of the seat of the bite. During a paroxysm the movements are usually violent, dangerous and even mischievous. There is constant restless movement, pawing, kicking the ground, the stall or attendants, lying down, rolling, rising, straining to urinate, or defecate, eversion of the rectum, shaking the head, muffled neighing, sniffing, snorting, everting of the upper lip, grinding of the teeth, or biting. In the absence of such paroxysms deglutition may be difficult, and the appetite depraved, the patient preferring earth or manure to the natural food. With spasms or paralysis of the pharynx, the food may be returned through the nose. In some cases a stiffness or impaired control of the limbs has suggested inflammation of the feet. In the uncastrated male and female generative excitement is the rule, the protrusion and erection of the penis, the swelling and rigidity of the clitoris, with frequent straining to pass water, the whinnying of the animal for its mate; attempts at copulation and even ejection of semen may be observed. The seat of the bite may be red, angry and itchy, so that the horse rubs, nibbles or gnaws it, often breaking it open anew. There is usually ardent thirst, and no dread of water, even when swallowing is difficult or impossible.

During a violent paroxysm the horse often bites the halter, blanket, manger, rack or stall, seizes the adjoining horse with his teeth, or gnaws, or tears strips of skin from his own shoulder, breast or limbs. In the same way he uses his feet with the most evident purpose of injuring man or beast that may approach him, or he breaks down his stall.

Even at an early stage there may be spasmodic movements of the eyes, face or body, and later there appear signs of paresis, often commencing in a hind limb and extending to paraplegia and general paralysis. Sometimes paralysis begins in the muscles adjoining the seat of the bite. The temperature, at first normal, may rise to 104° F. in the advanced stages, breathing and pulse are greatly accelerated, and the skin may be bathed in perspiration. Spasms are not entirely superseded by paralysis, and death often takes place during a convulsion, from the fourth to the sixth day. In apoplexy death may ensue in one day.