266 ABSTRACT::; AND REPORTS.

SPONTANEOUS RECOVERY FROM EXPERIMENTAL RABIES IN THE DOG, AND PERSISTENCE THE RABIC VIRUS IN THE SALIVA

OF OF

RECOVERED ANIMALS.

DR REMLINGER has recently submitted a note on the above subjects to the Central Society of Veterinary Medicine in Paris.

The author recalls that Pasteur, Roux, and Babes have on several occasions observed the recovery of animals which had been inoculated with the rabic virus and afterwards presented symptoms of the disease. Out of 159 dogs inoculated with the ordinary street virus, or with the fixed virus, either under the skin or dura-mater or into the eye, Hogyes observed six cases of furious or paralytic rabies which terminated in recovery without treatment of any sort. Kraiouchkine similarly reports that two dogs which had been inoculated under the skin with the fixed virus, and then wetted with water in order to study the predisposing effect of cold, presented symptoms of rabies, but subsequently recovered. Out of seventeen dogs inoculated into the muscles he saw one in which an injection of 5 cc. of emulsion produced the disease, but in which at the end of a week complete recovery had taken place. Courmont and Lesieur, again, relate that two dogs which had been inoculated into the brain recovered after having displayed slight but still distinct symptoms of rabies.

Remlinger has himself previously published observations regarding two dogs which received into the jugular an emulsion of the fixed virus of rabies, subsequently showed the classical symptoms of paralytic rabies, and finaliy recovered. The diagnosis in these cases was verified by proving that the serum of the dogs had rabicidal properties, since subdural inoculation had no result, the animals having acquired immunity.

The author has recently observed a third case of rabies which terminated in recovery. In order to establish the diagnosis he had recourse to inoculation of the saliva into the muscles of the necks of guinea-pigs. It appeared to him interesting to ascertain how long after recovery the saliva would remain virulent. The details of the experiments were as follows :-

On the 18th August 1906, in the course of some immunisation experiments against rabies, a street dog received under the skin of the ahdomen 20 cc. of a 1 per cent. emulsion of fixed rabic virus. On the 27th September one­tenth of a cc. of emulsion of the same virus was injected into the eye. The animal's health remained excellent up to the 23rd Octoher. On that day when the attendant took the animal its food it remained recumbent and ab50lutely refused to eat. When excited by means of an iron rod it got up. It then became furious, turned several times round in a circle, bit the bars of its cage, and barked with the tone typical of rabid dogs. The posterior limbs were in a state of paresis. During the day the same phenomena were repeated whenever the animal was excited, and it had several similar spontaneous attacks. During the next two days the animal showed a similar mixture of the symptoms of furiolls and paralytic rabies. The paralysis in the hind limbs increased, and it extended to the fore-legs and to the mllscles of the neck. The animal experienced great difficulty in standing, and it succeeded only by holding its fore-legs widely apart, so as to widen the base of stlpport. While the animal stood the head was pendulous, the nose touching the ground. It neither ate nor drank. On the 26th October the signs of excitement had disappeared. When the dog was called it wagged its tail and tried to get up, fell several times, but finally was able to totter as far as the bars of its cage. On the 28th October it was able to walk with less difficulty. It still refused food but it drank. On the 29th the paralYSIS had diminished, and the animal had eaten a little bread. Un the 30th it got up

ABSTRACTS AND REPORTS.

without much difficulty. The head was still hanging in consequence of the paralysis of the muscles of the · neck. Its appetite was better. During the following days it gradually recovered, and soon the only symptom left was a slight paralysis of the hind quarters. By the 5th November the animal could be considered completely recovered.

In order to establish the diagnosis of rabies, and to ascertain how long the saliva remained virulent, a plug of absorbent cotton-wool, moistened with sterilised water, was every three or four days between the 30th October and the 20th November used to mop up saliva from the dog's mouth, the liquid being then carefully expressed. The liquid thus obtained was on each occasion inoculated into the muscles of the neck of two guinea-pigs, and the following table shows the results :-

No. of Date. Nature of the Result. Animal. Inoculation.

Guinea-pig I 30th Oct. Injection of 3 cc. of Dead of rabies, 28th Nov. a dilution of the saliva into the muscles of the neck.

, 2 " " Abscess of neck; cachexia.

Dead, without symptoms of rabies, on 12th Nov.

" 3 4th Nov. "

Abscess of neck; profuse discharge. Death, with-out symptoms, loth Nov.

" 4 " " D ead of rabies, 1st Dec.

Rabbit I " " Dead 20th Nov. from

pasteurellosis. Guinea-pig 5 8th Nov.

" Survived.

., 6 " " " " 7 loth Nov.

" D ead of rabies, loth Jan.

Two passages; result positive.

" 8 " "

Dead, without discover-able cause, on 15th Nov. Two passages; result negative.

" 9 13th Nov. "

Survived.

" TO

" " Abscess of neck; multiple

suppurations. Dead, without symptoms of rabies, 25th Nov.

" II 15th Nov.

" Dead, without discover-

aoble cause, on 28th Nov. Two passages; result negative.

" 12

" " Survived

" 13 20th Nov. " " ,. 14 " " "

" IS " " "

268 ABSTRACTS AND REPORTS.

It is thus apparent that the dog was the subject of rabies, since of two guinea-pigs inoculated on the 30th October, while the ammal lIas still very ill, one died twenty-nine days afterwards with the classical symptoms of paralytic rafJies. The rabid virus persisted in the saliva at least five 'days after complete recovery. On the 5th November the dog no longer showed any morbid symptom, and even the paralysis of the hind quarters had disappeared. Nevertheless, of two gumea-pigs inoculated with the saliva taken on the loth November one died of rabies on the sixty-first day. The diagnosis was confirmed by two passages in the rabbit.

This observation is very similar to the important one made by Roux and Nocard, namely, that the saliva of the dog is already dangerous two to four days before the appearance of the rabic symptoms. Besides, as Roux and Nocard had foreseen, certain clinical facts go to prove that these figures fall below the reality.

Pampoukis has published an account of a case in which a woman who had been bitten by a dog eight days before it presented any suspicious symptoms, and who therefore did not think it necessary to submit herself to the Pasteurian treatment, consequently succumbed to the disease.

Zagario has also reported the case of a dog which bit another thirty days before it developed rabies; nevertheless, the second dog contracted the disease.

Remlinger thinks that probably his own figures are open to some reproach, seeing that on the lIth and 12th November, six and seven· days after complete recovery, the saliva was not tested by inoculation, and one of the two guinea-pigs inoculated on the 13th, that is to say on the eighth day, died prematurely as the result of an abscess at the seat of injection. Moreover, intramuscular inoculation is a rather uncertain method, and in each of the cases only a small quantity of saliva was injected.

Whatever be the virus employed (virus of the streets or fixed virus) or the method of inoculation (subcutaneous, intramuscular, intraocular, subdural) experimental rabies is thus in the dog a disease which may end in recovery. Is the same true of clinical rabies?

Several veterinary surgeons, including Bouley, have admitted this. Although there does not exist, apparently, any observation which would justify one in affirming it positively, there are certain facts which point in that direction. Pasteur was the fin,t to observe, although all authors who have experimented with rabies have since noticed it, that certain dogs are refractory to the disease. It is the more logical to explain this immunity by a previous attack, seeing that in Remlinger's case of recovery the severe test of subdural inoculation remained without any result. On the other hand, it is not exceptional to find in the antirabic institutes that a person who has not undergone the Pasteurian treatment succumbs to rabies, although the dog which bit him remains alive. Thus, Remlinger has already reported a case in which he was consulted by a young girl who feared that she had been infected from her sister, who had died some days previously [rom character­istic furious rabies. When the author demanded why the antirabic treatment should not be carried out, he was told that the dog which had bitten the first child on the foot five months previously had not shown any suspicious symptom, and was actually still alIve and well. The case is also well known of the man who was bitten by a suspected dog, which he brought for examination to Alfort. The animal was not recognised to be rabid, and it survived. The man succumbed after the typical interval to a disease, which was diagnosed as rabies by some, and as rabiform hysteria by others. The fact remains, however, that the patient died in forty-eight hours, which is an unheard of period for hysteria.

It would be easy to multiply these examples, and there are few directors of

ABSTRACTS AND REPORTS.

antirabic institutes who have not observed similar cases. Such cases are generally, and perhaps wrongly, supposed to be doubtful, as rabies is still considered to be a certainly fatal disease. Sometimes the death of the bitten person is attributed to another disease than rabies. In other cases it is supposed that the person has made a mistake wIth regard to the identity of the dog j or, again, that before he was bitten by the animal which survives he had been bitten, or licked where scratched, by another rabid animal. Remlinger does not consider that there is any possibility of explaining his case in this way. The diagnosis of rabies was made by three doctors, and it appears certain, on the one hand, that it was indeed the dog which remained alive that had bitten the patient, and, on the other, that the child had never been contaminated by any other animal.

It does not necessarily follow, however, that because a dog can inoculate fatal rabies without itself succumbing rabies is in that animal curable. Hypothesis for hypothesis, one may suppose that the dog which inflicts the bite has a short time previously had his lips, tongue, or teeth soiled with virulent products coming (rom a rabid animal. Although the researches which Remlinger has made in this direction had a completely negative result, it is nevertheless permissible to ask whether the rabid virus, like the pneumo­coccus or streptococcus, may not occur in the saliva of certain healthy dogs. Nevertheless, in the author's opinion, it is advisable to draw the very serious attention of doctors, and especially of veterinary surgeons, to the hypothesis that cases of clinical rabies in the dog may end in recovery.

Experimental rabies in the dog is spontaneously curable. That, according to the author, is an undeniable fact, and he holds that it is curable even when the inoculation has been a very severe one (subdural or intraocular), and although the virus employed has been the street virus. The author therefore inquires, why should not clinical rabies be also susceptIble of recovery? Does there exist in nature a single disease which is absolutely invariably fatal?

As IS well known, rabies presents itself with very variable symptoms in the dog, but one has an invincible tendency to admit that an animal which survives after having presented symptoms of an ambiguous character cannot have been attacked with rabies. This reasoning does not appear to be quite legitimate, as it amounts to a begging of the question. The author maintains that the question can only be resolved by long and careful experimental and clinical study. One ought to keep under observation dogs presenting rabic symptoms, however little suspicious, and then, in the event of the animal's survival, the question whether rabies existed or not ought to be tested by inocu­lating the animal into the eye or under the dura-mater, and observing whether it is immune or not. Some of its saliva ought also to be inoculated into the muscles of the necks of guinea-pigs. Finally, when the dog's recovery appears to be assured it ought to be killed, and its medulla ought to be used for the subdural inoculation of a rabbit. (Remlinger, Recueil de MM. vet., Tome lxxxiv., p. 269, 1907.)