Definition. Epizootic manifestations. Faulty hygiene, insanitary
stables, impure air, defective drainage, fermenting food, overwork,
overfeeding, excitement, heat exhaustion, electric tension. Probably
complex. Horse, ox, sheep, goat, dog. Microbian factors in man and
rabbit. Lesions: meningeal, brain and spinal congestion, effusion,
suppuration, circumscribed necrosis, softening, petechiæ. Blood dark,
fluid or a diffluent clot. Symptoms: _horse_: paresis, anorexia,
dysphagia, mucous congestion, reddish brown: in severe cases, chill,
stupor, apathy, debility, palsy, tonic spasms of neck, back or loins,
hyperæsthesia, twitching, trismus, hyperthermia, delirium, coma,
convulsions, and early death. Duration averages 7 to 15 days. _Ox_, as
in encephalo-meningitis. _Sheep_, microbes. _Dog_, dulled senses,
stupor, coma, palsy, hyperthermia, heat of head, spasms, etc.
Diagnosis: by brain and spinal symptoms; cases in groups. More sudden
than tetanus, or rabies, and shows no mischievous purpose, nor
depraved appetite: from tubercular meningitis. Treatment: Avoid
suspected stable, food, water, or suspicious environment, disinfect,
correct local diseases, unload bowels, belladonna, atropia, chloral,
bromides, ergot, phenacetin, potassium iodide. Bleeding. Cold to head
or back. Derivatives. Sling. In convalescence, regulated diet and
tonics.
_Definition._ Concurrent inflammation of the meninges of the brain and
spinal cord.
This appears at times in many horses in the same locality, as in New
York in 1850 (Large), in Denmark since 1852 (Stockfleth, Bagge), and in
Egypt in 1876 (Apostolides). In Cairo alone about 6,000 horses, mules
and donkeys perished. Hence the disease is known as _epizootic cerebro
spinal meningitis_. But again it is often seen in scattering or sporadic
cases. Add to this that no evidence has ever been adduced that the
disease is communicated from one animal to another, and in these days of
the parallelism of _epizootics_ and _pathogenic microbes_, we may well
hesitate about continuing to use such a qualifying term. Friedberger and
Fröhner claim “that a large number of clinical facts have been
erroneously reported under the name of spasm of the neck. Rabies,
tubercular basilar meningitis, apoplexy, simple encephalitis, and
certain poisonings have been confounded with that disease.” They assure
us that “cold, damp, chilly weather, hot stables, clipping and
overfeeding are of but secondary importance,” but they fail absolutely
to tell us what is of _primary importance_ in a causative sense.
American writers who have attempted to account for the disease have
groped somewhat blindly for causes in the idea of poison. Large charged
it on insanitary conditions, poisonous gases, and defective sewerage in
cities, and lack of drainage and deficient stable ventilation in the
country. J. C. Michener attributes it to foods undergoing fermentation
and considers it as a paralysis due to toxic fungi. W. L. Williams, in
Idaho, found the greatest number of cases in winter had been fed hay
made from alfalfa (lucerne) and timothy, though some had small grains
and native grasses. The soil was dry, porous, gravelly, devoid of humus,
and lying on lava rock. The altitude and clearness of the atmosphere
were supposed to exclude the idea of cryptogams, yet the crops generally
were raised by irrigation. The water was from clear mountain streams.
Stables were generally low and full of manure, with thatched roofs, but
hardly tight enough to be called close. In these cases the defective
stable room, the irrigation, the leafy hay (lucerne), and the probable
presence of ferments (bacteria), are the only suggestive conditions. In
a fatal outbreak which I saw among the Wilkesbarre, Pa., pit mules,
rain-soaked and badly fermented timothy hay, overwork in view of a
strike, and a Sunday’s holiday in an unshaded yard under a hot July sun,
in contrast with the previous darkness and coolness of the pits,
coincided to disturb the general health. In several of the Southern
States it is attributed to worm-eaten corn. Trumbower thinks it should
be traced to the parasitic fungi that grow on plants, grains, and
vegetation. In many instances the disease has appeared simultaneously
with the feeding on certain specimens of brewer’s grains, oats and hay,
so that to use Trumbower’s words these were the carriers if not the
prime factors of the disease.
In recognizing how much cryptogams and bacteria vary under different
conditions of life, and what various products they elaborate at
different stages of their growth, we can theoretically explain the
absence of the disease at one time and its presence at another under
what seem to be identical circumstances, as also the variety of symptoms
shown in different outbreaks. While this causation cannot be said to be
absolutely proved, it is not antagonistic to the facts in many of the
best observed outbreaks, and may serve as a hypothetical working theory
until actual demonstration can be furnished. The affection suggests a
narcotic poison introduced from without, rather than a disease due to a
germ propagated in the system.
This need not, however, exclude the operation of attendant conditions
such as overwork, plethoric feeding, excitement, close stables, heat
exhaustion, etc., which tend to bring about cerebro-spinal congestion.
Even the electric tension of Idaho, of the United States generally, and
of Egypt, in connection with their comparatively dry atmosphere, should
not be overlooked in considering the possible causative factors.
In all probability as we learn more of the true pathology of the
disease, we shall come to recognize not one, but several toxic
principles, and several different affections each with its
characteristic phenomena in the somewhat indefinite affection still
known as cerebro-spinal meningitis.
The malady has been described in horses, oxen, sheep, goats and dogs,
attacking by preference the young, which are not yet inured to the
unknown poison, and by preference in winter and spring, the periods of
close stabling, dry feeding and shedding of the coat.
In the absence of bacteriological data from the horse, it may be noted
that in man cerebro-spinal meningitis, has been commonly found to be
associated with the presence in the meningeal exudates of the
_micrococcus pneumoniæ crouposæ_, (Micrococcus lanceolatus
encapsulates). This is frequent in the mouths of healthy persons so that
some additional accessory cause must be invoked to increase the
susceptibility or lessen the protective power of the tissues. This has
been thought to be found in the concurrent presence of other bacteria,
the staphylococcus pyogenes aureus, pneumobaccillus of Friedländer and
the streptococcus pyogenes. Mosny appears to have established this for
the staphylococcus in the case of rabbits. With a given dose of the
micrococcus pneumoniæ death was always delayed for a fortnight, while
with the same dose thrown into one thigh, and the staphylococcus aureus
in the other, the rabbit died in one day. This enhanced potency
resulting from the presence of the golden staphylococcus has been
invoked to account for the germ making its way from the mouth to the
brain in cases of otitis, suppuration of the Eustachian tube, tonsilitis
or nasal catarrh. These remarks are intended to be suggestive, rather
than conclusive, as we have as yet no certainty that cerebro spinal
meningitis in the horse is caused by the same germ as it is in man.
_Lesions._ The lesions are usually those of leptomeningitis, or
congestion of the brain and spinal cord and often effusion into the
ventricles, with a serous exudation under the pia mater or into the
arachnoid cavity. This may be transparent and yellowish, or grayish and
turbid, or milky. In the sheep, Roloff has found purulent products under
the pia mater, around the roots of the spinal nerves, and in the surface
layers of cerebral gray matter. The marked hyperæmia on the surface of
the gray matter is a striking feature, and circumscribed areas of
necrotic nervous tissue and softening are not uncommon. Petechiæ are
frequent on the meninges, the brain, heart, lungs and kidneys. Granular
and fatty degenerations are also met with in these parenchymatous
organs. The blood may be dark and liquid or diffluent.
_Symptoms in the_ =Horse=. The mildest attacks are manifested by
paresis, or loss of perfect control over the limbs, or loss of power
over the tail, impairment of appetite and some difficulty of swallowing,
together with some congestion or reddish brown discoloration of the
orbital and nasal mucosæ. In other cases paralysis of one or more limbs
may supervene but without marked fever or coma.
The more severe forms are ushered in by violent trembling, or by stupor,
apathy, and extreme muscular weakness, or actual paralysis. In such
cases the animal may stagger or fall. Dysphagia or inability to swallow
is often a marked symptom, the saliva falling in strings from the lips.
Another common phenomenon is the rigid contraction of the muscles of the
neck, back and loins, the parts becoming tender to the touch and a more
or less prominent oposthotonos setting in. Twitching of the muscles of
the shoulders and flanks may be noticed. Trismus also is sometimes seen.
The breathing is usually rapid and catching and the temperature 104° to
106°. The pulse may be accelerated and hard, or weak and soft, or
alternating. The eyes are violently congested, of a brownish or
yellowish red color, and the eyeballs may be turned to one side.
Paroxysms of delirium may set in, when the animal will push against the
wall, or perform any of the disorderly movements described under
meningo-encephalitis. Sooner or later coma and paralysis supervene, and
death occurs in from five to forty-eight hours. In the most acute
(fulminant) cases the animal falls and dies in convulsions. On an
average the disease lasts from eight to fifteen days. In the more
favorable cases, without any supervention of coma, recovery may begin on
the third or fourth day.
_Symptoms in the_ =Ox=. These are largely those of encephalo-meningitis.
If they do not come on with the customary violence, there may be at
first difficulty in prehension, mastication and swallowing of food; a
rigid condition of the muscles of the neck, back, and sometimes of the
jaws, and twitching of the muscles of the limbs, neck, lips, or eyes.
For a time there may be hyperæsthesia, restlessness and irritability,
stamping of the feet or shaking of the head, then there is liable to
follow, dullness, apathy, stupor, coma and paralysis. As in the horse,
the distinction from ordinary encephalo-meningitis will at times rest on
the prevalence of the epizootic disease in the locality.
_Symptoms in_ =Sheep=. The attack is described as coming on with
weakness, dullness, lethargy, salivation, convulsions, oposthotonos,
grinding of the teeth, succussions of the body and limbs, heat of the
head, and stupor or paralysis unless death ensues during a paroxysm. The
congestion of the head and of the encephalic mucous membranes, and the
deviation of the eyes are constant features. Wischnikewitsch describes
an extended outbreak in sheep in which the brain lesions were
complicated by hepatization of the lungs, and bacilli were found in the
various exudates. This reminds one of the presently accepted cause in
man, which is, however, a micrococcus rather than a bacillus.
_Symptoms in_ =Dogs=. These are described as some aberration of the
senses, which gradually merges into stupor, coma and paralysis. While
the animal is able to keep on his feet he sways and staggers, runs
unconsciously against objects, or walks in a circle. There is heat of
the head, injected eyes, sometimes drawn back or squinting,
oposthotonos, and general spasms occurring in paroxysms. The duration of
the disease is about the same as in the horse.
_Differential Diagnosis._ From other forms of meningitis this is easily
distinguished. Fulminant cases almost all belong to this type, the fact
of the coincident implication of brain and spinal cord is strongly
suggestive of this form, and the occurrence of many cases at once,
without any demonstrable toxic or thermic cause, is tolerably
conclusive. From tetanus there is this added distinction, that the
disease does not set in so slowly, the spasms of the neck and back are
not so persistent, and stupor sets in early, in a way that is unknown in
lockjaw. Rabies is recognized by the slow onset, the characteristic
prodromata, the mischevious disposition, the depraved appetite, and by
the history of its local prevalence. Tubercular meningitis in cattle has
a similar association with tuberculous animals in the same family or
herd, and often by the local indications of tubercle elsewhere,
emaciation, unthriftiness, cough, flocculent and gritty nasal discharge,
enlarged lymph glands, pharyngitis, mammary disease.
_Treatment._ With a disease so fatal _prevention_ should be the first
consideration and especially when it appears in an enzootic form. Even
in the absence of a definite knowledge of its germ or toxin, it is
logical to avoid the locality, condition, food or water by which such
germ or toxin has presumably entered the system, together with every
unhygienic condition, which may have reduced the resistance of the
system and laid it open to the attack. The animals should be removed to
a clean, airy, building and the old one should be thoroughly emptied,
purified and whitewashed, the lime-wash containing 4 ozs. of chloride of
lime, or 1 dr. of mercuric chloride to the gallon. Drains and gutters
should have special attention and the animals should not be returned
until the stable is thoroughly dry. A change of feed is imperative when
there is any suggestion of damp, mustiness or fermentation, and even in
the absence of such indications, since the ferments and their products
may still be present in a dried condition. It should also be an object
to correct any morbid or pyogenic condition of the pharynx, Eustachian
pouch, nose or ear, by appropriate measures and the inhalation of
sulphurous acid or chlorine may be resorted to with advantage.
As medicinal treatment Large advises to give at the outset 1 oz. aloes
with one or two drs. of solid extract of belladonna and as an eliminant,
derivative and nervous sedative there is much to be said for it. In case
the difficulty of swallowing should prove a serious barrier a hypodermic
injection of ½ dr. barium chloride, 1½ to 2 grs. eserine, or 2 grs.
hydrochlorate of pilocarpin together with ¼ grain of atropin, may be
employed. As a substitute for atropin, ergot, potassium bromide, chloral
hydrate, chloroform, or phenacetin have been tried in different cases
with varying results. Iodide of potassium has been employed with
advantage in the advanced stages and in convalescence, and may be
usefully employed in the early stages as a sedative to the nervous
system, a deobstruant and an eliminant, if not as a direct antidote, to
the toxins.
Bleeding is generally condemned, yet in acute cases where there are
indications of active brain congestion, threatening convulsions or coma
it may tend to ward off a fatal result.
Cold applications to the head are generally commended. Bags of ice or
snow, irrigation with cold water, or cooling by running water at a low
temperature, through a pipe coiled round the head or extended along the
spine, will meet the purpose. Applied continuously this constringes the
blood-vessels within the cranium as well as on its surface, lessens the
exudation, and controls the pain and spasms. This may be advantageously
associated with warm fomentations to the feet and limbs, friction, or
even the application of stimulating embrocations to draw the blood to
these parts. In the smaller animals even warm baths may be resorted to
as a derivative, cold being meanwhile applied to the head and spine.
This not only lessens the vascular pressure within the cranium, but
secures elimination of toxic matters by both skin and kidneys. Cold pure
water should be constantly within reach.
A most important thing in the horse is to put him in slings, if he is at
all able to stand with their assistance. In decubitus he rests on his
side, with the head on the ground, and lower than the splanchnic
cavities. The result is a gravitation of blood toward the head. In the
sling, with the head fairly raised the gravitation is the other way and
the head is depleted. If the patient is too ill to be maintained in the
sling, he may be packed up with bundles of straw on each side, so that
his breast may lie on a thickly littered bed, and his head may be
elevated.
When convalescence sets in care must be taken to nourish with
non-stimulating, easily digested food, gruels, soft mashes, pulped or
finely sliced roots. In vomiting animals rectal alimentation may become
necessary. The rise of cranial temperature or the aggravation of brain
symptoms should be met as needed by the local application of cold, and
potassium iodide and iron or bitter tonics may be given if they do not
interfere with digestion.