Synonyms. Definition: Acute, infectious, cerebral disease, of domestic
and wild carnivora, shown by intellectual, emotional, and aggressive
nervous disorder, and extreme nervous excitability. Animals
susceptible: canine and feline animals, biting animals and those
bitten, of all warm blooded kinds; receptivity greatest in carnivora.
Geographical distribution: where population is most dense, trade and
movement most active—north temperate zone. Australia, Tasmania, New
Zealand, Azores, St. Helena immune—protected by quarantine. Islands in
Elbe, places with enforced muzzling. Causes: contagion; inoculation;
rutting; skunk bites; absence of flowing robes (men, children).
Virulent matters: saliva, bronchial mucus, flesh, blood (not in
sheep?), milk, (in advanced stages), nerve tissue. Morbific agent
particulate; filtered liquid noninfecting: blastomyces, bacillus,
found but not uniformly: claims of brain symptoms from each.
Viability; saliva virulent for 11 days; brain 3 weeks at 32° to 63°
F., for months aseptic and in contact with carbon dioxide; water 20 to
38 days; body in grave 44 days; virulence lost by drying in thin layer
yet kennels remain long infecting; glycerine preserves; robbed of
virulence by iodine, citric acid, bromine, chlorine, sulphurous and
mineral acid and cupric sulphate. Bites of men effective to 50 per
cent., protection by clothes, wool, flow of blood, cleaning of teeth
by succession of bites. Infection by licking, sneezing, coughing,
inhaling, feeding. Incubation 15 to 60 days in dog, 20 to 45 days in
horse, 14 to 60 days in sheep, swine and cattle, 14 to 64 days in man.
Prolonged cases doubtful. Symptoms in dogs: change in disposition,
more amiable or morose, dull, apathetic, excitable, unwonted silence
or howling, restless, depraved appetite, swallowing small objects,
searching, tearing sticks or clothes, licking cold stone or genital
organs, hiding in dark corner, dull expression, irritation where
bitten, hoarse voice, rabid howl, eyes follow unreal objects, snaps at
them, listens for unreal sounds, irritability, fury when threatened
with stick or shown another dog, bites without growl, bears master’s
blow in silence, eyes red, fixed, pupils dilated, squinting, lonely
wandering, biting, swimming rivers; restless excitement alternates
with torpor and seclusion, slouching gait when worn out; in _paralytic
form_; weakness, paresis, palsy of lower jaw, hind limbs, body, dull,
prostrate, apathetic; in lethargic form; no fury nor paralysis, but
profound prostration and apathy, no coaxing, threat, punishment not
even another dog will rouse. Paralytic and apathetic forms wind up the
furious; cases with intermittent attacks. Diagnosis: by marked change
of disposition or habit, voice, appetite, any hypersæthesia,
strabismus, watching or snapping at unreal objects, taciturnity, fury
in presence of other dog or stranger, snapping, biting without giving
voice, fury when threatened with stick, open mouth without disposition
to paw it, lack of muscular coördination, paresis, paralysis.
Distinction from lactation anæmia, bone in palate or throat,
dislocation of maxilla, stomato-pharyngitis, cutaneous hypersæthesia,
pharyngeal anthrax, epilepsy, pentastoma, cysticercus, filaria
immitis, nematodes, and tæniæ, auricular acariasis. Symptoms in
_cats_: changed voice, depraved appetite, hiding, restlessness,
irritability, bites, scratches, man or dog. Symptoms in solipeds:
trembling, hyperæsthesia, easily startled, ears and eyes alert,
dilated flashing pupils, roused by dog or stranger, attacks with teeth
and heels, mischievous, pawing, kicking, rolling, rising, straining to
urinate or defecate, neighing, sniffling, snorting, everting upper
lip, grinding teeth, biting, stiffness or impaired control of limbs,
generative excitement, spasms, paralysis, hyperthermia, perspiration.
Symptoms in cattle: irritability, restlessness, alert head, ears,
eyes, squinting, dilated pupils, loud bellowing, lashing tail, or
docility, yet pursues a dog, using horns, heels, (exceptionally
teeth), stamps, paws, has genital excitement, anorexia, spasms,
weakness, paraplegia. Symptoms in sheep and goat: hyperæsthesia,
irritability, genital excitement, fury in presence of dog, stamps,
butts, paws, snorts, bleats, grinds teeth, becomes paretic, and
paraplegic. Symptoms in camels and deer: camels show furious and
paralytic forms, biting and snorting; deer have hyperæsthesia merging
into paralysis. Symptoms in swine: extreme irritability, restlessness,
start at slightest cause or none, tremors, squealing, jerking,
grinding teeth, clenching jaws, bite especially a dog, or not,
weakness, lethargy, paralysis. Symptoms in rabbits and Guinea pigs;
may be furious, more often paralytic. Symptoms in birds: restlessness,
ruffling of feathers, pecking or striking man or dog, or at phantom,
palsy. Symptoms in wild carnivora: lose fear of man, approach and
attack him, are furious and later paralytic. Skunks bite slyly.
Symptoms in man: irritable cicatrix, anxiety, sighing, tremor,
insomnia, bad dreams, fever, thirst, spasms of throat when seeing,
hearing or taking liquids, dyspnœa, retching, vomiting, spasms, roused
by noise, squinting, dilated pupils, mental delusions, reticence,
taciturnity, suspicion, mania, exhaustion, paresis, paralysis.
Lyssophobia, its detection and cure.
_Synonyms._ Canine madness; Rabidus Canis; Lyssa; Lytta; Cynolyssa.
_Definition._ Rabies is an acute, infectious disease, affecting the
cerebral and medullary nervous centres and characterized by
intellectual, emotional, aggressive and other nervous disorders and by
extreme reflex excitability.
_Animals susceptible._ While the disease is seen most frequently in the
canine races (dogs, wolves, foxes and jackals), and in the cat family
(cat, lion), it is liable to spread widely among animals that use the
teeth as weapons of offense, and such as they can readily attack. When
inoculated, all warm blooded animals contract the disease. Thus the
carnivora and omnivora (dog, wolf, fox, hyena, jackal, cat, lion, badger
and skunk and, to a less extent, the pig and horse) may become active
propagators of the infection, which may spread widely among their
herbivorous victims (cattle, sheep, goats, deer, rats, mice, chickens
and pigeons) through their bites. Man suffers mainly through the attacks
of dogs, cats and, in certain localities, wolves or skunks, but he is
also liable to become infected from handling rabid domestic herbivora.
Different genera differ in susceptibility, the receptivity being
apparently greatest in the carnivora.
_Geographical Distribution._ Rabies is confined to no country nor
climate but it attains its greatest prevalence in the north temperate
zone, where there is the densest population and where activity of travel
favors the propagation of infection. The facility for inoculation is the
one determining cause, thus the islands of Australia, Tasmania, New
Zealand, the Azores and St. Helena have never suffered and the first
three exclude the disease by rigid inspection and quarantine. During the
Hamburg epizoötic of 1852–53, the islands in the Elbe escaped though
both banks were ravaged. Again, where the muzzling of all dogs has been
rigidly enforced, as in many German cities and districts the disease has
been practically extirpated.
_Etiology._ Long before the days of pathological bacteriology rabies was
recognized by veterinarians as a disease due to infection alone. Its
absence from the various countries above named, and from South and West
Africa, its rapid propagation in other countries (La Plata, Malta, Hong
Kong) into which it had been introduced for the first time, and its
restriction and disappearance wherever muzzling had been strictly
carried out, had practically settled this question. The development of
the disease in animals which had been experimentally inoculated was no
less significant of this truth.
Other alleged causes are based on secondary factors that favor
inoculation. The alleged evil influence of the hot season (dog days) is
accounted for by the period of _rutting_ of the dog which occurs in
spring, and brings together troops of jealous dogs following individual
bitches and fighting for their favors. This gives a great impetus to the
propagation of the disease which accordingly becomes more prevalent
during succeeding months. The statistics of Bouley show, however, that
the season of its greatest prevalence in France is March, April and May,
that it subsides slowly up to midwinter and encreases again in spring.
Boudin’s statistics show the greatest number of cases in man toward
midsummer which is explained by the long period of inoculation after
bites sustained in the spring, but also because clothing is lighter in
summer and infection more likely to reach the skin, and because the heat
of the weather tends to cause hyperthermia and encrease susceptibility.
The large preponderance of male dogs among the victims of rabies (7:1)
has led to the theory that sex predisposes, but the explanation is
rather that the males bite each other in their jealousy while they
respect the female, the object of their sexual passion. In inoculated
cases, males, females, and castrated contract the affection
indifferently and with equal readiness.
The skunk is found to be infected in certain localities, and it has been
claimed that the affection is native to this animal, and that the form
differs from that which prevails in the dog, but the restriction of the
disease to sharply circumscribed areas in Michigan and Kansas, while
skunks elsewhere show no such malignant quality, demonstrates that this
is but an accidental infection of the family of the Mephitis in a given
locality.
Men and children suffer in far greater numbers than women, the
difference being mainly due to the protection furnished the female by
the flowing skirt, though also in part because of the more frequent
contact of men with dogs.
_Virulent Matters._ In 1813 Gruner and Count Salm demonstrated the
virulent properties of the saliva of the rabid dog. This has been many
times repeated, though as shown by Pasteur, Raynaud, and others,
inoculations with saliva often kill in one or two days by reason of the
presence of other infective germs, or suppuration ensues and destroys
the rabific virus so that oftentimes not more than one in four develops
rabies. Galtier succeeded in inoculating 3 rabbits, 1 dog and 1 sheep
with the juice expressed from the salivary glands, and Nocard,
Leclainche and Peuch have found this to be very virulent. Paul Bert
found the bronchial mucus virulent. Rabies has been frequently conveyed
by consuming the bodies of rabid animals, yet Peuch and Galtier have
failed to convey infection by the flesh. Eckel and Lafosse successfully
inoculated the blood of goat to sheep, of man to dog and of dog to dog.
Yet many of the older observers agree with Peuch and Galtier in
pronouncing the blood non-virulent. Pasteur, Roux, Bujwid, and Helman
failed to obtain virulent cultures from blood. Peuch and Nocard have
found the milk virulent, and Bardach found the same to be the case in a
woman for two days before her death of rabies. In some partially
refractory animals like the sheep, the blood seems to destroy the virus,
as intravenous inoculations have been made with impunity. The
probability is that the blood is habitually non-virulent in the early
stages and in mild cases, but becomes virulent in violent and advanced
cases. Pasteur first showed that the virus has a special election for
the brain and nervous matter and that the central nervous organs are
constantly infecting. Rossi inoculated with a piece of nerve trunk, and
Doubouc and Babes advanced the hypothesis that the virus advances along
the nerve to reach the brain.
It was formerly supposed that the saliva of omnivora and herbivora was
non-virulent but repeated experiment has proved it to be infecting. The
blunder was due to the fact that these animals did not often transmit
the disease by biting. Some writers even deny that rabies exists at all
as an infectious disease. One alleges that the danger of rabies is
“_less than the gallows_.” Experiment shows most conclusively that it is
much more certain when the conditions are fulfilled. One may live a long
lifetime without seeing a genuine case of rabies, but so he may without
seeing leprosy or plague, and he is no more entitled to doubt their
existence than he is the existence of Manila, or of the other side of
the moon.
_Morbific Agent._ The actual factor which produces rabies is not
certainty known so that we cannot speak of its bacteriology. That it is
due to a specific particulate germ is now indisputable. Paul Bert and
Nocard filtered the virulent fluid through plaster and found the clear
fluid that had passed through non-virulent. Rivolta, Babes, Bouchard and
Peuch severally passed a solution of the rabific brain matter through a
Chamberland filter and found the clear filtrate harmless. The virulent
agent is therefore not a body in solution but a solid (organism) which
is held back by the filter. Hallier, Klebs, Galtier, Gibier, Pasteur,
Fol, Babes and Dowdeswell have respectively attempted the cultivation
and inoculation of organisms found in rabific liquids but none has stood
the test of further experiment. Memmo found a blastomyces in the brains
of six rabid rabbits and one hydrophobic child. It stains with the
aniline dyes but not by Gram’s method; when thrown into the peritoneum
of Guinea pigs it produced clonic spasms and death in 24 hours, and in
the dog, after an incubation of 8 days caused emaciation, salivation, a
disposition to bite, paralysis of the hind limbs and death in 48 hours.
Bruschettini using agar or bouillon, containing lecithin or cerebrin and
defibrinated dog’s blood, inoculated with pieces of the brain of an
inoculated rabbit, obtained in 24 to 36 hours a group of small
transparent drop-like colonies at first microscopic, but becoming larger
with each new culture on fresh media. These colonies contained a very
small, short, thick bacillus, which stains readily in Ziehl’s
carbol-fuchsin, and then presents a central clear band giving the
appearance of a diploccus. In fluid media spherical forms are produced,
but in fresh cultures the diploccus aspect reappears. Injected
subdurally in rabbits it gave rise to what appeared to be paralytic
rabies and could be inoculated from animal to animal, with similar
results. It failed to grow in the usual culture media from which the
brain products are absent, thus fulfilling the conditions, of a microbe
the point of election of which was the nerve cells. Marx who has sought
for Bruschettini’s organism in 60 cases of rabies has only once found
anything resembling it and concludes that it was merely a contaminating
organism, which caused a paralysis (Centr. f. Bacter. 1896.)
_Viability of the poison._ Galtier found that the virulent saliva
remained potent for 11 days if preserved from drying. It persists for 3
weeks in the brain and medulla kept at 0° to 12° C., for a month in
sealed tubes, or for several months if protected against septic microbes
and in contact with carbon dioxide.
In water it is preserved for 20 to 38 days so that water soiled with
saliva may easily become a means of infection. In graves it has been
found virulent as long as 44 days after burial so that in medico-legal
cases results may be obtained by exhuming a suspected animal (Galtier).
Haubner found that drying the saliva in thin layers rendered it
non-virulent and Pasteur has shown that the rabbit’s medulla loses its
virulence in 14 or 15 days when dried in contact with air, and apart
from putrefaction. Such laboratory results must however be qualified by
the facts recorded by Blaine, Youatt and others in which hound after
hound died of rabies from living in a dry kennel in which a rabid animal
had preceded them. Until we know something of the living germ itself of
rabies, it is unwise to infer too positive results from experiments on
that microbe, in what may be but one stage of its existence.
The virus is very resistant to cold, having survived a temperature of
−60° C. (−76° F.) for several hours (Roux), −10° C. (−14° F.) for ten
months (Jobert). Virulence is destroyed however by a temperature of 48°
C. (118.4° F.) in five to twenty minutes (Galtier). Light destroys the
virulence in 14 hours at 30° to 35° C. (Celli), but encreased pressure
has little effect on it (16 atmospheres, Nocard and Roux).
Glycerine at room temperature preserves the medulla in its full potency
for four weeks, but destruction ensues if it is heated (Protopopoff). An
aqueous solution of iodine (6:100) destroys the virulence (Galtier), as
does also citric acid, bromine, chlorine, sulphurous acid, the mineral
acids and cupric sulphate.
_Ratio of successful inoculation to bites of rabid animals._ As rabies
is usually transmitted by the bite, it is well to note that not all the
bites of rabid animals are effective. Of 183 dogs confined with and
bitten by a rabid dog 91 contracted rabies; of 73 cattle bitten 45
became rabid; out of 121 sheep bitten 51 succumbed and of 890 persons
bitten, 428 took hydrophobia. Of 440 persons bitten by rabid wolves 291
contracted the disease. The escape of such a large proportion is
variously accounted for. Wolves naturally attack the face, throat or
hands where there is no protection by clothing, and inoculation is
therefore much more certain. Dogs, especially in cold weather usually
bite man through the clothes which wipe off the virus from the smooth
conical teeth before they reach the skin. Long haired animals are often
protected in the same way. In other cases the bite is sustained on a
very vascular part and the free flow of blood washes out the poison. In
still other cases the rabid animal making a number of snaps in rapid
succession comes to the last with the teeth wiped clean and harmless.
Again the prompt washing or cauterizing of the wound tends often to
protect against infection.
Under favorable circumstances however every bite infects, and the writer
has seen six animals, bitten in the same stable, all contract rabies,
while a man bitten through the coat sleeve by the same dog, and
cauterized an hour later entirely escaped. If the bites are multiple,
deep and irregular, the danger is greater.
The licking of wounds is an occasional mode of infection, the rabid dog
in the early stages of the disease sometimes showing an unusual
disposition to fawn upon his owner.
Again particles of saliva may be projected by sneezing or otherwise and
lodge on sores, or on the mucosa of the nose, eye or lip so as to cause
infection. Galtier has conveyed the disease experimentally to rabbits in
11 cases out of 75 by making them breathe the atomized infecting liquid,
or by dropping it into the nose. In the same way he infected Guinea pigs
and sheep.
Galtier and Bujwid have conveyed the disease, exceptionally, to rabbits
and rats by feeding infecting emulsions. Galtier has also produced
rabies in ⅒th to ⅓d of the cases operated on by instilling the virus
into the eye.
_Incubation._ The duration of incubation varies with the species,
individual, the seat and character of the bite, the amount of virus
instilled, the potency of the virus, the age, size and weight of the
subject, the excitement of _rutting_, climatic or weather vicissitudes,
fatigue, and nervous or febrile disorders.
In the _dog_ incubation ranges from 15 to 60 days, and perhaps 4 to 6
months. It is claimed to have lasted a year but this is somewhat
doubtful. In _cats_ it has varied from 15 to 60 days.
In _solipeds_ it ranges usually from 20 to 45 days. The extremes stated
are 15 days and 20 months.
In _cattle_ it ranges from 14 to 50 days (exceptionally 70 days), in
_sheep_ and _swine_ from 14 to 60 days. It has been claimed to have
lasted 4 months in swine and 5 months in sheep.
In _rabbits_ subdural inoculation has an incubation of 15 days,
shortening in 25 removes to 8 days, and finally to 6.
In _man_ incubation is alleged to be even more varied. The rule is from
14 to 64 days, but it is claimed to have been as short as three days and
as long as 1 to 12 years (Chabert). In the human being, however, there
is always the danger of the disease caused by simple dread (lyssophobia)
and until these protracted cases can be verified by successful
inoculation on the lower animals, they must be held as extremely
doubtful. The Montpellier cadet has been often quoted who left, a few
days after he had been bitten, spent ten years in Holland, then
returning to the school and learning for the first time that his fellow
cadet, who had been bitten by the same dog, had gone mad, he too became
rabid without loss of time. Such cases have often been cured by moral
suasion and have been seized upon to corroborate the heresy that there
is no such thing as genuine rabies in man.
Any incubation, in man or beast which has exceeded 40 days should be
considered as doubtful, until certified by the successful inoculation of
rabbits or other small animals. For casual inoculations the incubation
rarely varies much from the time embraced between 16 and 30 days. It is
abridged by a special receptivity; by an overdose of the poison; by the
inoculation of a virus of unusual potency; by the youth of the animal
inoculated; by great heat of the weather; by all forms of violent
excitement; by _rutting_; and by the inoculation of the virus on the
head and above all on the cerebral meninges. By this last method
incubation may be reduced to 6 days.
_Symptoms in Dogs._ In dogs as in other animals rabies is manifested in
two great types: the _furious_ and the _dumb_ or _paralytic_, which,
however, usually succeed each other in fully developed cases. Yet the
_furious_ phenomena may be entirely omitted, and again the victim may
die in the early _furious_ stage so that the paralytic does not appear.
The prominence of one form over the other is to some extent determined
by the germ derived from a previous case of the same kind or by the
family, temperament and habits, bull dogs and hounds being specially
subject to the furious type, and house and pet dogs having rather the
paralytic form.
The _premonitory symptoms_ are in the main the same for both types, and
as these may enable us to recognize the disease before the period of
extreme danger, it is especially important that they should be well
understood.
Some marked change in the disposition or habits of the animal is the
first obvious variation from health, and in a district or country where
rabies exists any such change should be the warrant for instant
seclusion of the dog before there is any disposition to bite. The
unwonted habit may be of almost any kind. The lively, amiable dog may
become suddenly dull, apathetic or taciturn; the quiet, unexcitable dog
may become unusually affectionate, fawning and demonstrative, licking
the owner’s hands and face and perhaps infecting him before any
suspicion is aroused. Sudden capricious changes from fawning to apathy
or sullenness, or the opposite, should be dreaded. The noisy dog may
become suddenly silent; while the silent dog may take to howling without
apparent cause. A great restlessness, watchfulness or nervousness, a
tendency to start at the slightest sound, and a disposition to move at
frequent intervals in search of an easier position or place to lie in,
are most dangerous symptoms. A morbid appetite, with a disposition to
pick up and swallow all sorts of nonalimentary objects (straw, thread,
cord, paper, pins, nails, coal, marbles, pebbles, cloth, earth, dung or
urine), in a mature dog is most suggestive. Searching around, scraping,
tearing sticks, clothes and other objects to pieces, licking of smooth
cold stone or metal, of his penis, or of the generative organs of a
bitch, are often early phenomena. The dog may hide in a dark corner,
going to sleep and grumbling or growling when disturbed. He may make
night hideous with his howls, _baying at the moon_. He may stand with a
dull, melancholy, hopeless expression of countenance, as if beseeching
his master for relief from his nameless suffering. But as yet there is
no disposition to bite. The dog still responds to the call of the
master, but with dulness and apathy, in marked contrast with his usual
prompt, alert and loving response. There may be congestion, itching and
irritation in the seat of the bite, and it may be licked, scratched or
gnawed until raw, tender or bleeding. An early change in the voice may
be noticeable. There is at first a certain hoarseness, which gradually
develops into the pathognomonic rabid howl which is quite recognizable
at a distance. The dog turns his nose upward, and with open mouth, emits
a howl which, at first hoarse and low, rises into a shriller and higher
note before completion and which may be repeated several times without
closing the mouth. It is not an ordinary howl but rather a cry of
distress, and, to the educated ear a grave note of warning. Sometimes
the dog is dumb from the start.
Close observation will often detect evidence of mental delusions and
hallucinations even at this early stage. The apparently sleeping dog
suddenly starts up with an air of suspicion and excitement. His eyes may
turn after phantom flies or other objects at which he will presently
snap. He moves hither and thither with a curious, inquisitive air,
searching in dark corners, or under curtains or articles of furniture
for some imaginary object. He may stand in attentive attitude listening
to fancied sounds, and then bound in that direction in spite of an
obstructing wall or utensil. If recalled to reality by his master’s
voice his healthy attitude and affection may be completely though
temporarily restored. He may compose himself to rest or sleep, and soon
again start a victim to further delusions.
The _furious stage_ is ushered in by a more pronounced manifestation of
the above symptoms. The rabid howl is more frequent and characteristic.
The insomnia and the restless movements, change of place, searching,
scratching or tearing are likely to be more prominent. The delusions and
the watching or snapping at phantoms are more marked. The causeless
sniffing and scraping may imply disorder of the sense of smell. The
exalted hyperæsthesia and reflex excitability is usually a most marked
feature, frequently modified by a sinister, inimical or malevolent
disposition. Some subjects show evidence of intense itching, most marked
perhaps in the seat of the wound; others are abnormally sensitive to
currents of cold air; they start at the slightest noise, a flash of
light, a touch, or the approach of a stranger. A paroxysm of fury may be
caused at once by shaking a stick at the patient, but, above all, by the
test of presenting a dog before his eyes. He at once rouses himself and,
with flashing eyes, dashes himself on his supposed enemy and bites
viciously, but without bark or growl. The sudden and mute attack is
pathognomonic. But there may be symptoms suggestive of some
hypoæsthesia. A blow from the dog’s master is usually borne in silence.
The animal shrinks from the blow but does not yelp nor howl. During a
paroxysm he will lacerate his gums or loosen his teeth by biting on a
stick or iron bar; he will even seize a red hot bar without shrinking.
He will often gnaw his limbs or body so as to expose and even lacerate
the muscles, driven by the pruritus, or the insatiable disposition to
bite. Yet he has still an instinct of self preservation, retiring from a
light, or blazing brand, and seeking to evade the tongs used to seize
him.
The eyes assume a remarkable expression. They are often fixed, and at
times the pupils are widely dilated allowing the reflection of light
from the brilliant tapetum lucidum, resembling flashes of fire, and
adding greatly to his ferocious appearance, and the sense of terror that
he inspires. The conjunctiva is congested, of a dark red and the general
expression of the eye is very striking. The soft, trusting, affectionate
eyes may still for a moment meet those of the loved master, but there is
in them a dull, hopeless, anxious and suffering expression, which
appeals for pity and should be viewed with dread. To others there is
likely to be less of the affectionate appeal and more of the sinister,
suspicious, resentful and malicious expression. To the stranger,
therefore, the eye may be a better guide than even to the owner.
Squinting of the eyes and closure of the lids for a few seconds are not
uncommon. As the disease advances the dilatation of the pupils is more
marked, indicating the paralysis of the optic nerve.
In this stage the disposition to wander is characteristic. The rabid dog
leaves his home and wanders off a long distance, say ten or twenty
miles, snapping in his travels at man or beast that may irritate him,
returns dirty and exhausted, and seeks anew his dark place of seclusion,
or he may snap at and bite even his master. To those who come in contact
with him at this time the dog is especially dangerous from his extreme
irritability though weak and exhausted.
If the wandering rabid dog meets a strange dog he attacks him and bites
without growling or barking. If the bitten dog does not yelp nor
retaliate, but simply flees, the rabid animal moves on, but if he bites
back, or howls, he worries him, rolling him over and biting again but
always in silence, in marked contrast with an enraged but healthy dog.
If he comes up with a herd of cattle or pigs or a flock of sheep or
fowls, the result is similar. If they remain perfectly still they may
possibly entirely escape, but if they scamper off with noise as usually
happens, he rushes at them and bites one after another, so that in a
confined yard or park all may suffer. A man meeting the dog increases
his danger by making an outcry, whereas if he remains perfectly quiet he
may possibly escape. Bouley says that a canine attendant is, in a sense,
a measure of protection to a man, as the rabid dog attacks first the
animal of his own species, giving the man a chance to escape.
In his wanderings the rabid dog will swim rivers, having _no dread of
water_, just as at home he will plunge his nose in water though unable
to swallow. When abroad in this way he exhausts himself by his paroxysms
and may perish in one of them, or he may meet his death from man or
animal. He may in his exhausted state seek a dark secluded place where
he may remain for a time and renew his travel later, or he may pass into
the paralytic condition and gradually sink.
When shut up, and his vagrant disposition curbed, the paroxysms are
liable to appear intermittently, a period of torpor and quiet
alternating with one of restless movement, searching, scraping, howling,
biting of any animals within reach and later of men, beginning with
strangers. A paroxysm can usually be roused by shaking a stick at him
and always by presenting another dog.
There is sometimes a difficulty in deglutition, the dog acting as if he
had a bone in his throat which he was trying to dislodge, and fatal
bites have been sustained during well meant attempts to remove the
hypothetical bone. This bears a resemblance to the pharyngeal spasms
which are such a marked feature in the hydrophobic man. But it is not
roused, as in man, by the sight or sound of water. On the contrary,
water is sought and often swallowed at first and even, exceptionally,
throughout the disease. He may even take his usual food for a time. The
bowels are usually torpid, and any fæces passed are black and fœtid.
Diarrhœa may set in later.
In the early stages the rabid dog walks or trots like any other dog. It
is only when exhausted by wandering, or violent paroxysms, or both, that
he droops his head and ears, hangs the tail between the legs, and
slouches along with arched back, and unsteady, swaying limbs. The
appearance of these last symptoms implies advancing debility and
paresis, and the near approach of paraplegia. The symptoms may, however,
be temporarily relieved by a period of seclusion and quiet.
In _dumb_ or _paralytic rabies_ the striking peculiarity is the omission
of the preliminary furious stage, and the disease merges at once into
paralysis after the premonitory symptoms. In these cases the early
nervous symptoms tend to prostration, weakness and dulness or even
stupor, there is no disposition to escape, but rather to seek seclusion
and quiet, there is rarely howling and then only at first, and soon
there is paralysis of the masseters and dropping of the lower jaw, and
there is neither ability nor desire to bite. From this the paralysis
extends to the hind limbs and then to the fore limbs and trunk. In other
cases one limb is the first to suffer, followed by the face, limbs and
body. The most prominent feature is the widely opened mouth, the
flaccid, hanging tongue and drivelling saliva. The buccal mucosa, at
first red and moist, becomes bluish, dry and powdery. The eyes are dull,
mournful, suffering or altogether without expression and the pupils are
usually widely dilated. The hind limbs are usually utterly helpless and
often the fore ones as well, the prostration is extreme and the patient
lies quiet and helpless until released by death in two or three days.
A third form, known as the _lethargic_, is a modification of the
paralytic. There may be neither delirium nor marked paralysis, there is
no drooping maxilla, pendant tongue nor stringy, hanging saliva, but
only a profound, nervous prostration and complete apathy. The patient
curls himself up in some dark, quiet corner and cannot be roused by
coaxing or punishment, by hunger or thirst. In this, as in the dumb
rabies, the common test of presenting another dog fails to rouse
excitement or paroxysm. If left undisturbed, these patients may live to
the tenth or fifteenth day.
Beside the typical forms there are all intermediate grades, inclining
more or less toward the furious, or the paralytic or lethargic. Galtier
mentions cases that showed aphasia, scarcely any disposition to bite,
swaying movements of the body and limbs, muscular incoördination, tucked
up, tender abdomen, rolling the body like a barrel, and marked dyspnœa.
Others show at first a slight disposition to bite which is quickly
checked by a very early paralysis of the masseters. In still others the
attempts to bite are still seen after dropping of the jaw, but though
still moved, it cannot be completely closed.
In exceptional cases rabid dogs have shown _intermissions_ of apparent
soundness extending over eight days (Youatt), two months (Pasteur), or
even six months (Perrin). Rare as these are they must apparently be
accepted, and must qualify to some extent the trust reposed in
immunization.
_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.
Cases in which paralysis is not preceded by a furious stage are not
uncommon in horses.
_Symptoms in Cattle._ Cattle are frequent victims of rabies, which
assumes mostly the furious type, yet in certain outbreaks the paralytic
or lethargic form predominates. There is first a strange irritability
and restlessness, very unlike the habitual quiet disposition of the
animal. The head is raised, the ears alert, the eyes prominent, red,
fixed, with occasionally widely dilated pupils and brilliant flashes
from the tapetum lucidum. Sometimes they roll or squint. They may appear
wild and ferocious or dull and hopeless. Loud and terrified bellowing is
not uncommon, switching of the tail, drivelling of saliva, and
exceptionally there are attempts to bite. More commonly the natural
weapons of offense are employed, the animal kicks, stamps, paws and,
above all, tries to gore man or beast, but especially any dog which may
appear. They even make such attacks on purely imaginary beings and
without any real, tangible enemy present. The bull, cow or heifer
present the usual signs of genital orgasm. Appetite is lost or depraved
and rumination arrested. Pharyngeal spasms or paralysis is not uncommon,
and signs of colic with frequent defecation may be seen. Violent
paroxysms are easily roused by the sight of a small animal and
especially of a dog. In these attacks the animal may break his horns or
teeth or otherwise injure himself. Sometimes the infection wound becomes
irritable, itchy and red or even abraded and raw by licking.
The animal becomes rapidly exhausted and even emaciated by the violence
of the paroxysms, and paresis sets in with dragging movements of the
hind limbs, which advance to paraplegia and general paralysis. Rolling
of the eyes, squinting and pupillar dilatation may be present. Death
usually takes place from the fourth to the sixth day.
The purely _paralytic rabies_ is not uncommon in cattle. There may be
persistent yawning or other sign of nervous exhaustion or depression,
halting on one or more limbs, usually behind, which advances to complete
paralysis. In other cases the symptoms are those of mental dulness, and
profound lethargy with gradually advancing emaciation. In paretic and
paralytic cases the characteristic paroxysms on presentation of a dog
may be absent.
Ladague claims to have seen intermittent cases with an interval of 27
and even 36 days.
_Symptoms in Sheep and Goat._ In these there is the same regular
succession of symptoms through intense hyperæsthesia and excitability,
fury and genital excitement to the terminal paralysis, or the palsy may
set in early without premonitory violence. Among the marked features
have been noticed, a change of expression, the pupils dilate, eyes
flash, they lick or mount their fellows, they lick or rub the bitten
part, snort, stamp or scrape with the fore feet, setting themselves in
the attitude of attack, they may butt other sheep, fowls, and other
animals, above all dogs, or they may deliver the attack in the air only,
at some phantom enemy. They may bleat hoarsely or brokenly, grind the
teeth, or work the jaws with the formation of froth about the lips.
Galtier says they may even attempt to bite. Sooner or later weakness of
the limbs, muscular incoördination, swaying and staggering bespeak
enervation, the sheep lies constantly, and if raised stands with
unsteady semi-flexed limbs, has trembling or convulsions and dies
paralytic in from two to five days. Death has been delayed till the
twelfth day (goat) or thirteenth (sheep). In some cases paralysis has
been present from the start, the subject lying prostrate from the first.
_Rabies in the Camel and Deer._ In Algiers camels are often times bitten
by rabid dogs and contract the disease showing both furious and
paralytic symptoms. They are especially dangerous because of their
propensity to bite, and to scatter the virulent product by sneezing.
In England rabies has prevailed extensively in parks of deer, which shut
inside high walls have been bitten remorselessly by rabid dogs that had
gained admittance. The symptoms of hyperæsthesia and paralysis followed
the same general course as in other animals.
_Symptoms in Swine._ Rabid pigs are usually very restless, excitable and
sensitive to all causes of disturbance. They will hide under the litter
in the darkest corner but soon start without apparent cause, turn around
and lie down again, or they bound up with grunt or scream and rush off
as if pursued, push or leap against the wall, stand with ears pricked as
if listening, and start violently at any noise or a flash from a
lantern, trembling, squealing, or having muscular jerking. The eyes are
at times fixed, or may roll, squint or flash from pupillary dilatation.
The voice is hoarse, deglutition difficult, there is frequent clenching
of the jaws, or grinding of the teeth, and frothing around the mouth.
The victim may tear with his teeth the boards of his pen, or gnaw pieces
of wood, he may swallow wood, pebbles or earth, and plunge his face in
water or other liquid without fear or apparent dread or dislike. The
disposition to bite may be viciously shown, and he may strike
dangerously with his tusks, while in other cases it may be entirely
absent. Peuch quotes cases in which no paroxysm was aroused by the sight
of a dog, and others in which the pig would rise and grunt without
showing any desire to bite.
Sows will sometimes bite or devour their offspring during a paroxysm,
yet nurse and care for the survivors during the intervals.
Emaciation, weakness, exhaustion, lethargy and paralysis appear early,
the victim remains down, or, if raised, moves weakly and unsteadily and
no longer pays attention to noises nor blows. Death may ensue from the
first to the sixth day.
_Symptoms in Rabbits._ Experimental cases in rabbits are now very common
and usually assume the paralytic or lethargic type, there is weakness in
the hind parts, advancing in a few hours to paraplegia, the fore limbs
may be used for a time while the hind are flaccid and dragged behind, or
the animal lies on the sternum and belly with the head sunken and
resting on the feet, or he lies extended on his side, in a state of
insensibility. In the early stages he may still masticate, with froth
collecting on the lips, but there is difficulty in swallowing. If a foot
is pinched it is drawn up often with a cry. The bowels are torpid though
a few small, round, hard pellets are sometimes passed or a little urine.
Incubation is shorter than in the dog, and the virus retains this habit
when inoculated on other animals.
In the experimental cases in the Anti-rabic Institute in St. Petersburg,
Helman found that the rabbits inoculated with virus from dogs having
furious rabies, contracted furious rabies, while those inoculated from
the less furious type of street rabies had the disease in the dumb form.
_Symptoms in the Guinea-pig._ In this animal as in the rabbit the
disease has been mainly seen in the experimental form, and has assumed
the paralytic type. It trembles, moves stiffly or weakly, lies most of
its time and passes rapidly into paralysis. There is usually no tendency
to bite, yet Peuch in a case of intraocular inoculation from a rabid cat
observed the most violent excitement, loud hoarse screaming, bounding in
different directions, biting of the wires of the cage, and other
manifestations of violent rabies. In both forms there are liable to be
convulsive movements of the jaws, accumulation of frothy saliva, and a
free discharge of urine.
_Symptoms in Birds._ Chickens bitten by mad dogs have been seen to prove
restless, erecting the feathers and moving aggressively toward man or
dog or phantoms of their imagination and attacking with bill or spurs or
both. This, however, rapidly advances to paralysis and death. In cases
due to intracranial inoculation on the other hand, somnolence, lethargy,
or coma appeared early, and was quickly followed by paralysis. This
affects especially the legs and neck. Recoveries are common and the
animal is thereafter immune. Subsidence, with complete intermission of
symptoms, is more common than in rabbits, the disease reappearing later,
and perhaps finally ending in recovery.
_Symptoms in Wild Carnivora._ The rabid wolf, fox, jackal, hyena,
coyote, ferret, polecat and skunk lose their fear of man, and approach
and attack him either in field, village or city. The disease has its
furious and paralytic stages as in the dog, and the animals attack
according to their nature, wolves being dangerous from flying at the
face and throat, and skunks from stealing up and biting without warning.
_Symptoms in Man._ After the period of incubation prodromata may be
present, or there may be suddenly and without any premonition, violent
spasms of the pharynx and inability to swallow. The premonitory symptoms
when present consist in irritability of the cicatrix which becomes red
or blue, swollen, itchy or pricking, and an aura or shooting pain may
extend from this toward the heart. There is anxiety, sighing, tremor,
restlessness impelling to frequent change of place, insomnia,
disagreeable or painful dreams, weariness, and gloomy forebodings. The
face is pale and drawn, and the eyes wander or have a look of
apprehension. There is some fever and often marked thirst, and the
attempt to swallow rouses slight spasm or a sensation of tightness in
the throat. The fauces, pharynx and eyes are congested, reddened and it
may be swollen. Pulse and respiration are both quickened, the
inspiration being often prolonged and sighing, and the expiration
sobbing. At first the intellect is unimpaired; there is no illusion nor
hallucination.
In cases in which premonitory symptoms are lacking, violent spasms of
the throat and chest are commonly roused by an attempt to drink and this
is so painful that the patient cannot again be induced to try. After
this any suggestion of drinking, the offer of drink, the noise of
trickling water, the sight of water, the sight of a vessel in which the
water was contained, or even of a clear shining surface of glass or
metal is likely to bring on a paroxysm. This hydrophobia is peculiar to
man being rarely seen in rabid animals. During a paroxysm dyspnœa is
extreme, respiration is gasping or sighing, and in the attempt to
dislodge the tenacious mucus which is present in the throat, hoarse or
shrill inarticulate sounds are emitted which have been supposed to
resemble the bark of the dog. There is a sense of closure of the throat
and of rising of the stomach, and retching or even vomiting may ensue.
Hyperæsthesia, reflex irritability, and exaltation of the special
senses, now become extreme, so that a paroxysm may be brought on by the
slightest disturbance, a current of air, a bright light, the rustling of
a dress, the noise of a footfall, the noise even of talking, or a slight
touch. The “tendon reflex” and skin reflex are often much encreased.
During a paroxysm there are muscular trembling and clonic
spasms,—sometimes opisthotonos. The intervals of complete relaxation,
however, serve to distinguish from tetanus. The face is red and drawn,
the eyes congested and sometimes squinting, the pupils dilated and the
expression one of suffering, apprehension and horror. Mental disorder
appears sooner or later, the speech is disconnected, with indication of
delusions from which the patient may at first be recalled by the
attendant. There is, however, a constant disposition to be reticent,
morose and above all, suspicious, as shown by the absence of a direct
look, and the frequency of side glances as though in expectation of a
hidden danger. This may even rise to mania, the patient charges those
about him with having caused his sufferings, or with conspiracy to
injure him, and he may seek to defend himself with hands, feet, teeth or
any available object. The necessary restraint aggravates and prolongs
the attack. On its subsidence the patient collects his scattered senses,
regrets, apologizes, and warns against future occurrences of the same
kind which he realizes to be beyond his control. Sometimes the delusions
continue during the remission as well. Sexual excitement is common in
man as in animals.
The convulsive paroxysms may last ½ to 1 hour, and they tend to encrease
in duration and force. A violent paroxysm may cause sudden death from
asphyxia or apoplexy.
Sooner or later exhaustion and paresis appear. The convulsions become
gradually weaker, the reflex irritability and hyperæsthesia abate, and
the patient may become once more able to swallow, but an ascending
paralysis, beginning in the limbs spreads over the body and death occurs
in from one to eighteen hours. In the paralytic stage there may still be
slight jerking of the muscles, or tremors, but violent convulsion no
longer occurs, and there is extreme prostration, with hurried, rattling
breathing, small, weak, irregular pulse and finally, stupor and coma.
_Diagnosis in man._ The only additional point, to those already stated
for animals, is in regard to _lyssophobia_. This false form of
hydrophobia is usually fortified by the fact of a bite, but as a rule it
lacks the exaltation of common sensation and of the special senses which
characterizes genuine hydrophobia. Very often also there is a flaw in
the history, the dog that inflicted the bite is unknown and may still be
alive, in which case no medicine is so good as to bring the healthy dog
into the presence of the patient. The dog may have been killed by an
excited community without any identification of his symptoms as those of
rabies or any post mortem examination to throw light on his case. The
attack may have come on after a conversation on the subject of the bite,
or of rabies, and perhaps, as in the case of the Montpellier cadet, long
after and when the patient had for the first time heard that the dog
that bit him had been mad. It may be that rabies does not exist in the
district and that no other victim in man nor beast can be adduced. It
may be that the patient has a nervous organization or is subject to
hysteria, and therefore specially predisposed to any disease of the
imagination. Such cases cannot be accepted as rabies until a successful
inoculation has been made on one or more animals.