Hydrophobia or Rabies

HYDROPHOBIA or RABIES, an acute disease occurring particularly in dogs, and liable to be communicated by them to other animals and to man. In the nerve cells from cases of rabies, and in no other disease, certain bodies, named after Negri, their discoverer, are found with so much regularity that they are held to be diagnostic of the disease. Moreover, if rabies be trans ferred experimentally to other animals Negri bodies are found in their brains also. Negri bodies are p. in diameter and their relation to the filter-passing virus of the disease is uncertain. They are not found in the saliva.

In Dogs, etc.

The occurrence of rabies in the fox, wolf, hyaena, jackal, raccoon, badger, and skunk has been asserted; but probably it is originally a disease of the dog. It is caused by a filter-passing virus and is communicable to other warm blooded creatures. The affected animal, at a certain stage of the disease and upon slight excitement, tends to attack with its natural weapons—dogs and other carnivora attacking with teeth, herbivore their hoofs or horns, and birds with beaks.

Symptoms.

The malady, which runs its whole course in about a week, commences with a change in the habits of the dog; it becomes dull and uneasy and seeks to isolate itself in out-of the-way places, and is apt to gather up straw, thread, bits of wood, etc., to lick anything cold, as iron, stones, and to lick other animals. Sexual excitement is frequently an early symptom. At this period no disposition to bite is observed. These symptoms gradually become more marked ; snapping and excited movements occur, but the dog still recognizes its master's voice; restless ness and agitation increase.

There is no dread of water in the rabid dog; the animal is thirsty and, if water be offered, will lap it with avidity and swallow it—at the commencement of the disease. And when, at a later period, the constriction about the throat—symptomatic of the disease—renders swallowing difficult, the dog will,none the less endeavour to drink.

At first the dog does not usually refuse to eat ; but soon per version occurs, and the litter of its kennel, wool, wood, earth, stones, or whatever else may come in its way are devoured. A mad dog does not usually foam at the mouth. The saliva is not much increased in quantity, but soon becomes viscid and clings to the angles of the mouth, fauces, and teeth. Thirst is great, and the dog sometimes furiously attempts to detach the saliva with its paws. There is another symptom connected with the mouth in that form of the disease named "dumb madness," which has frequently proved deceptive. The lower jaw drops, from paralysis of its muscles, and the mouth remains open. In this condition the creature cannot bite but the saliva is none the less virulent. The mouth should not be touched, numerous deaths having occurred through people, thinking a dog had some foreign substance lodged in its throat, thrusting their fingers down to remove it. Vomiting of blood occurs in some cases.

The voice of a rabid dog is characteristic. Owing to the altera tions taking place in the larynx the voice becomes hoarse, cracked, and stridulous, like that of a child affected with croup. A high toned bark with open mouth is immediately succeeded by six or eight decreasing howls. This alteration in the voice is frequently the earliest indication of the malady. In dumb madness the voice is frequently lost from the first—hence the designation.

Though cutaneous sensation is much diminished, mental excit ability is increased. A rabid dog is usually stirred to fury at the sight of one of its own species. All rabid animals, even the sheep, indeed become furious at the sight of a dog, and attack it.

In most cases such a dog is inoffensive, in the early period of the disease, to those to whom it is familiar ; but it is continually endeavouring to escape, and, when free, runs aimlessly forward, perhaps attacking every living creature it meets. It attacks in silence, and should it be hurt in return it emits no cry or howl of pain. The degree of ferocity appears to be related to natural disposition and training. Some dogs only snap in passing, others bite with such violence as to break their teeth, or even their jaws. Soon paralytic symptoms become evident in the intervals of exhaustion between paroxysms; the limbs become feeble and are dragged ; the walk is unsteady, while drooping tail and head, open mouth, and protruded tongue present a very characteristic picture. At last, exhausted, it shelters itself in an obscure place— frequently a ditch by the roadside—and lies there in a somno lescent state until paralysis and coma end in death.

In other species of animals the symptoms differ more or less from those manifested by the dog, but they are generally marked by a change in the manner and habits of the creatures affected, combined with paroxysmal ferocity.

In Man.

The disease is communicated to man by the saliva of the affected animal entering a wound or abrasion of the skin or mucous membrane. In go% of cases this is due to the bite of a rabid dog, but bites of rabid cats, wolves, foxes, jackals, etc., are occasionally the means of conveying the disease. The period of incubation of the disease appears to vary in a remark able degree, being in some cases as short as a fortnight, and in others as long as several months or even years. On an average it seems to be from about six weeks to three months, but it mainly depends on the part bitten ; bites on the head are the most dangerous. The incubation period is also said to be shorter in children. The rare instances of the appearance of hydrophobia many years after the introduction of the poison are always more or less open to question as to subsequent inoculation.

When the disease is about to declare itself the wound, which had quickly and entirely healed after the bite, often begins to exhibit evidence of irritation or inflammation or to be the seat of numbness, tingling, or itching. Knowing he has been bitten, the patient's symptoms during the premonitory stage are great mental depression, restlessness, and indefinite fear. There is an unusual tendency to talk, and articulation is abrupt and rapid. There is also some feverishness, loss of appetite, sleeplessness, headache, great nervous excitability, respiration of a peculiar sighing or sobbing character, and even occasionally a noticeable aversion to liquids. These symptoms—constituting what is termed the melancholic stage—continue in general for one or two days, when they are succeeded by the stage of excitement. Sometimes the disease first shows itself in this stage, without antecedent symptoms.

The agitation of the sufferer now becomes greatly increased, and the countenance exhibits anxiety and terror. There is marked embarrassment of the breathing, but the most striking and terrible features of this stage are the effects produced by attempts to swallow fluids. The patient suffers from thirst and desires eagerly to drink, but on making the effort is seized with a violent suf focative paroxysm, produced by spasm of the muscles of swallow ing and breathing, which continues for several seconds and is succeeded by a feeling of intense alarm and distress. Indeed the very thought of drinking suffices to bring on a choking paroxysm, as does also the sound of running water. The patient is extremely sensitive to any kind of external impression ; a bright light, a loud noise, a breath of cool air, and contact with any one are all apt to bring on one of these seizures. There also occur general con vulsions, and occasionally a condition of tetanic spasm. These various paroxysms increase in frequency and severity with the advance of the disease, but alternate with intervals of comparative quiet, in which, however, there is intense anxiety and more or less constant difficulty of breathing, accompanied with a peculiar sonorous expiration, which has suggested the notion that the patient barks like a dog. In many instances there are fits of maniacal excitement, succeeded by calm intervals. During all this stage of the disease the patient is tormented with a viscid secre tion accumulating in his mouth, which from dread of swallowing he is constantly spitting about him. There may also be noticed snapping movements of the jaws as if he were attempting to bite, but these are in reality a manifestation of the spasmodic action which affects the muscles generally. There is no great amount of fever, but there is constipation, diminished flow of urine, and often sexual excitement.

After two or three days of suffering of the most terrible descrip tion the patient succumbs, death taking place either in a paroxysm of choking or from exhaustion, all the symptoms having abated and the power of swallowing returned before the end. The dura tion of the disease from the first declaration of the symptoms is generally from three to five days.

Apart from the inoculation method (see below), the treatment of most avail is excision or cauterisation of the part bitten. This should always be done as soon as possible after the injury, even though Pasteur treatment is to follow.