Synonyms. Definition: infectious disease, due to bacillus, and shown
by tonic spasms of groups of voluntary muscles. Animals susceptible:
warm-blooded animals—dogs and chickens least: ⅔ds solipeds, ⅐th
cattle. Pathology and Causes: Bacillus tetani: 4 to 5µ by 0.2 to 0.3µ,
often enlarged by spore at one end; anærobic, liquefying, tardily
motile, until spore forms, grows in ordinary, alkaline media under
hydrogen, death point 60° to 65° C. (140° to 149° F.), for spores 80°
C. (176° F.), for an hour, dried it lives for years, in putrid matter
2½ months, stains easily, saprophytic in garden mould, in ingesta of
man and horse, abundant in tropics; infection local, killed by oxygen
in blood, toxins tetanize: tetanin, spasmotoxin, toxalbumin, diastase;
spasms first local near wound, then abruptly general, intravenously
causes general spasms first, theory of fermentation in blood; changes
in nerve cells, neuroglia, ependyma, peripheral nerves: muscles soft,
pallid, red, ruptured fibres, ecchymosis; rigor mortis early, marked:
sarco-lactic acid. Accessory causes: traumas and their causes,
parturition, umbilical infection, alimentary. General symptoms:
incubation 3 to 15 days, minimum 6 hours; tonic contraction of muscle
groups of locomotor system beginning near infection wound,—trismus,
orthrotonos, opisthotonos, emprosthotonos, pleurosthotonos, ocular
muscles; costive, difficult urination, hyperæsthesia, irritability,
perspiration, hyperthermia, mastication, deglutition, sucking.
Symptoms in _horse_: neck raised concave above, nose elevated,
nostrils wide, eyes sunken, haw protruded, ears rigid, pricked, facial
muscles rigid, prominent, mouth drawn back, muscles of back hard, tail
elevated, trembles, limbs extended outward, stiff, stilty, jaws
clenched or open slightly, stands. Symptoms in _cattle_; _sheep_ and
_goat_; _swine_; _dogs_; _birds_: Course: violent cases with short
incubation are rapid and fatal; mild ones with prolonged incubation
hopeful; cattle slow, sheep, goats and dogs acute. Mortality: sheep
and pigs 100 per cent.; horses 75 to 85; cows 70 to 80; lambs very
fatal. Death from asphyxia, hyperpyrexia, or exhaustion. Lesions:
trauma, often healed; congested nerves, gray horns of myelon, increase
of cells and granules in nervous matter of cord, corpus striatum,
cerebellum; blood extravasations at torn muscle fibres, intestinal and
cystic congestion. Diagnosis: from _strychnia poisoning_ by slow
advance, and persistence of spasm; from _rabies_ by absence of bite,
the continuous masseteric spasms, by absence of resentment, mischief,
hallucinations or depraved appetite; from _rheumatism_ by the
persistent trismus, hyperæsthesia and excitability; from _meningitis_
by the trismus, perfect mentality, absence of clonic spasm; from
_tetany_ by shorter and less perfect remissions, failure to develop
under nerve pressure, or improve under thyroid extract; from
_laminitis_ by the absence of high early hyperthermia, heat and
tenderness of the feet, and advance of hind legs under the body.
Treatment: best in slight cases, after long incubation, with slow
progress; antispasmodics; rest, darkness, absolute quiet, no litter,
nor visitors, slings, sloppy food, gruels, milk, green food, at level
of manger; clothing to favor perspiration; excision or antisepsis of
wound, carbolic acid, bleeding, opium, prussic acid, potassium
cyanide, bromides, physostigma, eserine, chloroform, sulphonal,
trional, tartar emetic, tobacco, apomorphia, lobelia, phenacetin,
acetanilid, cocaine, chloral, phenic acid, iodine terchloride, iodide
of potassium, orrotherapy, antitoxin; best as a preventive, value
decreases with development of disease; cerebral injections; brain
emulsion; use up toxins in blood; no use if nerve centres are already
in combination with toxins, only to ward off fresh toxin. Toxins
produce leucocytosis. Prevention: disinfection of all dirty wounds,
injections of phenic acid, or iodine; remove foreign bodies, use
muriatic and carbolic acids; antisepsis of navel; disinfection of
stables, feet, careful shoeing; immunization.
_Synonyms._ Lockjaw. Trismus.
_Definition._ An infectious disease of animals and man, characterized by
tonic spasms of the voluntary muscles in a given region or more
generally, with exacerbations, and dependent on the bacillus tetani.
_Animals susceptible._ Immunity cannot be claimed for any class of warm
blooded animal. Experimentally the dog and chicken prove among the most
refractory, in keeping with the comparative insusceptibility of the last
named animal to strychnia, but neither can be held to be in any sense
immune. Inoculated frogs become tetanic if the temperature is maintained
above the normal standard. In 208 cases in domestic animals recorded by
Cadiot and Hoffmann, 140 were in horses, 10 in mules, 5 in asses,
(solipeds, 155), 28 in cattle, 9 in sheep, 5 in goats, 5 in pigs, and 6
in dogs. Such statistics are liable to prove misleading when we have no
means of comparing them with the members of the different genera from
which the cases were drawn and the relative exposure of each genus to
traumatic lesions (infection atria). Solipeds lead with practically ⅔ds
of the entire number of cases, but these were presumably the most
numerous of the domestic animals, and preëminently the work animals and
therefore the most liable to traumatism. Cattle follow with ⅐th of all
cases but here again the large numbers to be drawn upon, and the
proportion of work oxen and wounds, are to be considered. The omnivora
and carnivora are comparatively little susceptible and among these the
chicken may be included. The omnivorous rat is quite susceptible.
Tetanus occurs in 1 per 1000 sick horses in the Prussian army
(Friedberger and Fröhner), and in 1 per 3000 sick in that of Wurtenburg
(Hering). It is so prevalent in San Domingo that a gelding costs twice
as much as a stallion (Wagenfeld). Heat and filth favor its
preservation.
In man tetanus is most frequent as the result of wounds (in feet and
hands) which are most likely to come in contact with the soil, and it
has visibly decreased in connection with the general adoption of
antiseptic surgery.
_Pathology and Etiology._ Sir James Simpson suggested in 1854 that
puerperal and surgical tetanus was due to the absorption of a poison
produced in the wound (Woodhead). Spinola charged it on infection in
wounds in horses. Carle and Rattone in 1884 successfully inoculated 11
out of 12 rabbits with the products from the wound of a man suffering
from tetanus. A year later Nicolaier produced tetanus in animals by
inoculating them subcutem with garden mould or street dust, and found in
the suppurating wounds in connection with various other microbes a
minute bacillus longer but thinner than that of mouse septicæmia to
which he attributed the tetanizing action. In 1886 Rosenbach inoculated
two Guinea pigs with the pus of a tetanic man, and found in the sores of
the tetanic pigs the bacillus of Nicolaier in company with another
larger spore-forming bacillus. In 1889 Kitasato succeeded in making pure
cultures of the bacillus tetani, and successfully inoculated the disease
on mice, rabbits, and Guinea pigs producing typical tetanic symptoms and
death. This was promptly corroborated by Tizzoni and Cattani and later
by a great variety of observers.
_Bacillus Tetani._ This organism is a minute rod 4 to 5μ in length by
0.2 to 0.3μ in thickness, with slightly rounded ends. In many mature
forms the one end is enlarged by the formation of a spherical,
refrangent spore which gives the bacillus the appearance of a pin or a
“drum-stick.”
The bacillus is anærobic, liquefying, tardily motile, and sporogenous.
When spores form the bacillus loses its motility. It grows at room
temperatures, in ordinary culture media which have a feebly alkaline
reaction, and in an atmosphere of hydrogen, but more actively at a
temperature of 36° to 38° C. Below 14° C. growth ceases and the bacillus
is killed at 60° to 65° C. The spores, however, can resist a temperature
of 80° C., in water for an hour, and 100° C. for four minutes. It was
this unusual resistance of the spore to heat that enabled Kitasato to
kill off the contaminating organisms and obtain pure cultures from the
surviving spores. The spores will survive desiccation for years,
retaining their virulence, and may live 2½ months in putrefying
material. The addition to the culture medium of 1½ to 2 per cent. of
glucose makes the growth much more rapid and abundant, and causes
opacity in the medium. The upper portion clears up in 6 or 7 days by the
precipitation of the bacilli as a grayish mass. In a glucose culture
medium growth is not prevented by the presence of oxygen at the surface.
The colonies formed in gelatine plate cultures show an opaque centre
with fine divergent rays, and a similar radiating growth is shown in
deep stick cultures. At the end of the second week the gelatine begins
to liquefy and form a little gas, and finally the whole mass becomes
soft and sticky. The bacillus does not liquefy blood serum. Cultures
have a disagreeable aromatic odor.
The bacilli stain readily in aniline colors and by Gram’s method. The
spores may be stained by Ziehl’s method. To 10 parts of a 10 per cent.
alcoholic solution of basic fuchsin, add 100 parts of a watery solution
of carbolic acid. Float the cover glass upon this, heating gently for
three to five minutes until steam begins to rise, wash well in water,
and decolorize in nitric or sulphuric acid, 25 per cent. solution, then
in 60 per cent. alcohol to remove color from albuminous background. Wash
in water and mount. By placing the specimen for two minutes in a watery
solution of methylene blue a contrast is obtained, the bacillus blue and
the spore red.
Outside the animal body the bacillus has a saprophytic life in rich
garden mould, street dust, stables, yards and drains, and the cracks of
floors. Nicolaier failed to obtain it in soil from forests and from the
deeper layers of garden earth. Marchesi found it to a depth of two
metres but no more. Again it is much more abundant in tropical countries
than in temperate and cold ones, and appears to be to a great extent
limited to particular localities. It has been found in the intestinal
contents of man and horse (Babes, Sormani), and in horse manure, and
this mingling with the surface soil and generating an abundance of
ammonia determines the anærobic conditions which favor the growth of the
microbe. This serves to explain the remarkable prevalence of the disease
among those living or working about stables, gardeners, agricultural
laborers, soldiers on campaign, and children and others walking with
bare feet. The contact with rich infected soil greatly favors
inoculation in any accidental wound.
An important feature in the pathology of tetanus is that the bacillus is
confined to the seat of the inoculation wound. The many attempts to
transmit the infection by blood, nervous matter, and by one or other of
the tissues have uniformly failed, though the pus of the infected wound
has proved virulent. Similarly, the attempts of Kitasato and others to
obtain cultures from the animal liquids or tissues apart from the wound
have been futile.
By inoculating the toxins remaining in the pus of the infection wound,
however, or in virulent cultures from which the bacilli have been
removed by filtration or in which they have been destroyed by heat, all
the symptoms of tetanus can be produced (Kitasato, Kund Faber, etc.) In
such cases too, the symptoms appear at once, as soon as the toxin is
absorbed, and not after a definite period of incubation as in
inoculation of the unaltered virus. Kitasato, Vaillard and Vincent
reached this conclusion by another channel. They inoculated mice at the
root of the tail with virulent tetanus cultures, and at definite
intervals after, namely, half an hour, one hour, and one and a half
hour, they made a circular incision round the wound and thoroughly
cauterized the whole, thus destroying all the inoculated bacilli. They
found that tetanus was prevented in those animals only which were
operated on at the first half hour. Again, Kitasato injected mice with
0.2 to 0.3cc. of the blood from the heart of a fresh tetanus cadaver,
and thereby produced typical tetanic symptoms and death in 1 to 3 days.
Various poisons have been separated from cultures of bacillus tetani.
Brieger isolated three substances—tetanin, tetano-toxin and
spasmotoxin—which in large doses caused tetanic symptoms and even death.
Brieger and Fränkel later isolated a toxalbumin which proved of
incomparably greater potency. Again, Brieger, Kitasato and Wehl
separated what appeared to be an enzyme or diastase which proved 500
times more potent than atropia. This was in the form of yellow,
transparent flakes, soluble in water, but which was not destroyed by
drying, nor in the dry state by absolute alcohol, chloroform nor
anhydrous ether, but which, like the virulent cultures of tetanus, was
easily destroyed by acids, alkalies, hydrogen sulphide, or heat. Like
the natural virulent product this may be kept unchanged for months on
ice, apart from the light, or with the addition of 0.5 per cent. of
carbolic acid, or its own bulk of glycerine. It kills the Guinea-pig in
a dose of 0.000025 gramme, and the mouse in a dose of 0.00000025 gramme.
While the propagation of the bacillus in the animal body appears to be
local, and the general tetanic symptoms are caused by the absorption of
the poison, it remains to be seen on what organ this directly operates,
and what accessory conditions favor its efficiency.
In _cases due to inoculation_ the spasms are at first local in the
vicinity of the inoculation wound and later become general. Kund Faber
shows that there is no gradual transition from the local manifestations
to the general, but the latter appear abruptly and in force as a new and
independent phenomenon. When we consider further that in inoculation
with pure cultures (uncontamininated by pus or saprophytic microbes) the
wound often heals promptly, without any sign of remaining local
irritation, we may conclude that simple nervous irritation in the sore
cannot be invoked as a cause of the early local spasm. It is more likely
due to the local diffusion of the poison into the peripheral nerves
while the little that has been absorbed is as yet too much diluted in
lymph and blood to seriously derange the nerve centres.
When general spasms set in it must be assumed that the poison has
reached the nerve centres in toxic quantities, either through the
circulation or as is alleged by Babes and others through the nerve
trunks. When the poison is injected intravenously the general spasms are
the first to appear. Again the section of the nerves of a limb before
inoculation prevents spasms in its peripheral muscles when all the body
beside has become tetanic (Tizzoni and Vaillard). The removal of the
brain from a tetanized frog had no effect, while the removal of a
portion of the spinal cord abolished the spasms in the muscles
corresponding to that part. Moreover Gumbrecht cut the whole of the
sensory nerves of a limb but the spasms occurred in its muscles
notwithstanding. It must be admitted, therefore, that the general
tetanic spasms are induced by disorder caused by the poison in the
spinal nervous centres.
Gumprecht and Goldscheider claim that the poison reaches the spinal
centres by way of the nerve trunks basing the conclusion on the
observation that the spasms sometimes remain for a time more marked on
that side of the body on which the wound or inoculation was made.
Absorption through the circulation also is conceded.
Courmont and Doyon claim that the product of the bacillus tetani only
operates as a ferment, which produces in the blood the real tetanizing
agent, basing the conclusion on an apparent delay in its action, in man,
as compared with strychnia, and on the prompt action of the injected
blood of a tetanic animal in which this poison is presumably preformed.
It should be noted, however, that the disease in man is only seen after
accidental inoculation of the bacillus, and that time must be allowed
for the increase of the microbe.
Vaillard and Vincent have shown that the promptitude and certainty of
the result depend on the age of the culture employed. A culture of 5
days in bouillon at 20° to 22° C. will not harm a Guinea pig in a
hypodermic dose of 0.25cc. to 0.5cc. A culture of 20 days old is deadly.
The action on the nerve cell of the spinal cord has been investigated by
Goldscheider and Flatau, who found degeneration of the chromatin
granules within a short time after inoculation. (Centr. für Allg. Path.
Anat. 1897). W. K. Hunter found that the ganglion cell stained more
diffusely than normal cells. There were also some capillary dilatation
and punctiform hæmorrhages in certain cases (Brit. Med. Jour. 1897).
Péchoutre examined the lumbar enlargement of tetanic rabbits, by Nissl’s
method and found the following lesions in the motor cells of the
anterior horns: 1st. A partial or total disappearance of the distinct
outer marginal line; enlargement of the cell and pericellular space;
diffuse coloration of the achromatic substance; a disappearance of the
regular concentric disposition of the granules of Nissl which were in
part reduced to a fine powder; 2d. Encrease of nucleus and nucleolus.
Others have observed encrease of the cerebro-spinal fluid, thickening of
the ependyma, nuclear proliferation in the neuroglia, and softening of
the cord, but in many cases no appreciable lesions in the nerve centres
have been found, and none can be affirmed as constant. Neuritis in the
region of the wound is sometimes found especially if the lesion is a
contused or painful one.
The muscles often show lesions the result of the violent contractions.
There may be points of ecchymosis and partial rupture of individual
fibres, they may be of a deep red, or again pale, soft and as if
parboiled. There may be hyperæmia or œdema of the lungs, congestion of
the larynx, ecchymosis on the pericardium and other serous and mucous
membranes, and congestion of the liver, spleen and kidneys. Rigor mortis
sets in rapidly and is usually very persistent. The muscles contain an
excess of lactic acid.
_Accessory Causes._ Whatever contributes to traumas must be classed in
this list. Solipeds, work oxen, and dogs are especially exposed in this
sense. In all animals castration wounds; in horses and lambs amputation
of the tail; in solipeds pricks, bruises and fistulæ of the feet; all
kinds of surgical wounds; in females the parturient condition; and in
the new born the umbilical sore form infection atria. The tendency to
infection in wounds of the feet in animals, and of the hands and feet in
man, is easily explained by contact with the virulent earth or dust.
Children running barefoot, or injuring their bare knees and soldiers
sleeping on the ground are similarly exposed. The contamination of the
clothes is the main condition. It has been held that infection never
takes place from the gastro-intestinal canal, but the facts that the
bacillus is frequently present in the prima viæ and that the mucosa is
often perforated by blood-sucking parasites, suggest that some cases
(idiopathic) are probably due to intestinal infection. The gland ducts
also and the follicles of Peyers’ patches and of the solitary glands
offer available fields for the colonization of the bacillus and for
infection atria.
_General Symptoms in Animals._ In experimental cases, in which there has
been a large intravenous injection of the blood of a victim of tetanus
the symptoms may set in speedily and violently. In casual cases,
however, there is usually an _incubation_ period varying on an average
from three to fifteen days in the _horse_ while it may be as short as
two days in _cow_ and _sheep_. Hoffmann quotes one incubation in the
horse as but six hours after a wound in the neck, and another as
twenty-five days, following a castration. The last is rather unreliable
as infection may have taken place long after the operation. He quotes
cases in the pig and goat, after castration as eight to fourteen days,
and one in the dog almost immediately after a bite on the loins.
Following the incubation the marked phenomena are tonic contractions of
groups of muscles beginning usually with those near to the seat of the
infected wound and extending with varying rapidity to the locomotor
muscles generally (limbs, croup, back, loins, neck, tail, abdomen) and
those of mastication (jaw) and the eye. The muscles of respiration are
only involved at a late date, causing stertorous breathing and it may be
asphyxia. Peristalsis is impaired so that there is some costiveness and
tardiness in digestion. Urination becomes difficult and infrequent on
account of the difficulty of assuming the normal position for the act,
and spasm of the sphincter vesicæ and dangerous distension of the
bladder may follow. The urine is often albuminous and has a high density
and color. Priapism is not infrequent in the male.
The predominance of the spasm in special groups of muscles has been the
occasion of giving different names to individual cases.
_Trismus_ or _lockjaw_ is that condition in which the muscles of the
jaws are violently contracted so that the incisors can only be separated
slightly or not at all.
_Orthrotonos_ is that condition in which the muscles in tonic spasms
keep the neck, back and loins rigid, straight and unbending, in one
horizontal line.
_Opisthotonos_ is when the muscles of the spine are in rigid spasm, so
that the back and loins are slightly depressed, the tail elevated and
trembling, the neck drawn upward with a concave superior border
(“ewed”), the head extended and the nose elevated.
_Emprosthotonos_ is caused by spasms of the muscles of the ventral
aspect of the body, with arching of the back and tucking up of the
abdomen.
_Pleurosthotonos_ is when the trunk is spasmodically bent to one side,
right or left.
Spasms of the muscles of the eyeball, cause sinking and apparent
diminution of that organ, with the protrusion of the membrana nictitans
over one-third, one-half or even more of its front surface. This is
often referred to by owners as “hooks”.
More striking and pathognomonic than the above is the extreme
hyperæsthesia and irritability which rouse into activity or aggravate
the symptoms under the slightest cause of disturbance. The effort
required to feed from the ground, the stretching of himself to urinate
or defecate, the rustling of straw litter under his feet, loud talking,
or other sudden noise, banging of doors or windows, hammering in the
vicinity, a current of cold air, a flash of light, moving the patient in
the stall, attempts at mastication, simple handling, administering
medicine, or sudden jerking of the head upward promptly brings on a
paroxysm of spasm. Pushing the head suddenly upward or jerking on the
halter, is often resorted to as a means of diagnosis, the sudden
resulting rigidity of the muscles generally, the rolling of the eye, its
retraction toward the depth of the orbit and the protrusion of the
membrana nictitans over one-half, one-third or more of the cornea,
bringing out the diagnostic symptoms in a striking manner. In very
severe cases the head may be drawn upward and backward almost to above
the loins (Henry), or one or more of the dorsal or lumbar vertebræ may
be broken or crushed (Zundel). A sudden loud noise will sometimes cause
the exhausted animal to drop to the ground.
Perspiration is not uncommon. Breathing is usually accelerated, the
encrease being in ratio with the violence of the spasms. Pulse and
temperature are usually normal at first and may be in slight cases
throughout. Even in severe cases the pulse does not rise so much as the
respiration. In violent and fatal cases the temperature often rises
excessively before death (104° to 110° F.).
When the jaws are not absolutely closed, the tongue is often wounded by
the teeth, and, in any case is covered by a tenacious mucus, which may
hang in strings from the lips. If the jaws are still movable,
mastication is still carried on, but slowly, painfully and imperfectly,
and deglutition is more or less difficult. Young animals are unable to
suck.
_Symptoms in the horse._ When the symptoms are fully developed, they are
very characteristic. The neck is raised, often concave along its upper
border, the nose raised and protruded more or less, the nostrils widely
expanded, the eyes sunken, fixed and anxious, with diluted pupils and
protrusion of the haw outward and upward from the inner canthus, the
ears are pricked, rigid, and drawn toward each other at their tips, the
facial muscles may stand out visibly and are firm, the angle of the
mouth is drawn back, the veins of the head are full and prominent,
saliva froths or drivels from the lips, the tail is elevated and during
paroxysms will tremble, and the muscles of the back and limbs are
projecting and hard. The limbs are extended outward to give a wider base
of support. If moved, the general stiffness is at once seen. The patient
cannot be turned round in his stall, he may not even be able to turn the
neck to one side, and if backed he resists, or accomplishes the movement
only with the greatest difficulty. In walking, the limbs are used as
stilts with little or no bending of the joints, and if turned, the body
is not bent but moved around with difficulty as if one rigid mass. The
pulse is small and hard, the breathing slightly hastened, and the mucosæ
congested and reddened. The jaws may be firmly closed, or they may still
part for a time half to one inch. In all severe cases the patient
obstinately stands, and if he should drop, or lie down, the breathing
and spasms are usually encreased and, in the efforts to rise, the
respiratory muscles may become spastic with promptly fatal results.
In _cattle_ the same general symptoms prevail. The stiffness of neck and
back, the habitual elevation of nose and tail, the stiffness of the
legs, propped outward for support, and moved like unbending posts when
made to walk, the hardness of the muscles, standing out under the skin,
the rigidity of the lips, firmly closed or slightly opened, the general
fixity of the erect, retracted ears, and the sunken appearance of the
eyes with marked protrusion of the haw, are largely as in the horse. The
muzzle is usually dry and hot, the jaws clenched, the tongue firmly
compressed against the palate and covered with thick, tenacious mucus,
and the flanks are often flattened by the contraction of the oblique
muscles, so that they descend almost vertically from the lumbar
transverse processes. There is great difficulty in turning and the trunk
moves in rather a rigid mass without bending laterally, and the limbs
are stiff and stilted. Tympany of the rumen sets in early with oppressed
breathing and arrest of defecation and urination, which had been already
difficult. The reflex excitability to noises, or other causes of
disturbance is often less than in the horse. In cases following
metritis, this may be due in part to the depressing poisons absorbed.
_Sheep and Goat._ Show the same general rigidity of trunk and limbs, the
drawing of the head and neck upward and backward, the elevation of nose
and tail and the firm closure of the jaws. As the disease advances they
may lie on the side with legs straitened and rigid and head and tail
raised toward the back. The occlusion of the eye by the haw is the same
as in the horse.
In _swine_ the spasms begin with the jaws and face, and extend to the
neck, back and limbs with the same general symptoms as in other animals.
Champing of the jaws and profuse frothing at the mouth have been noted
and the protrusion of the haw is characteristic. As in sheep, the animal
may lie on its side with head and limbs rigid and an early death may be
looked for. Convulsions are easily distinguished by their transient
character.
_In dogs_ tetanus is rare. Möller had two cases in 50,000 sick dogs,
Friedberger and Fröhner but one out of 70,000. Cadiot saw two cases in
ten years of the Alfort clinic. Labat had several cases in sheep dogs. A
slight transient trismus has been noticed as common in puppies. When
generalized there is stiffness of the trunk and limbs, abduction of the
members. The spine may be straight and rigid or drawn upward and
backward, and the loins depressed. The haw covers the eye more or less,
the lips are rigid, the jaws clenched, and the skin of the forehead
wrinkled. The ears are stiff and drawn toward each other, or backward.
The reflex excitability is as great as in the horse, the slightest touch
or sudden noise producing violent paroxysms. Inability to bark is a
marked feature. Temperature may be normal or up to 107° F.
_In birds_ it is very rare, in keeping with the insusceptibility to
strychnia, ergot and other tetanizing agents. Dreymann gives one case in
a _turkey_, and Babes’ experimental cases in pigeons and chickens from a
specially virulent bacillus obtained from the horse. The pigeons
suffered much more certainly and severely than the chickens, in which
there was a marked power of resistance. Dreymann’s turkey moved with
stiff limbs and body, had the wings clinging firmly to the body, the
head and neck extended and the bill firmly closed. The haw protruded
over the eye, and there was hurried and oppressed breathing.
_Course._ _Duration._ The course of tetanus varies with the genus
affected, with the individual susceptibility and above all with the
length of the incubation, and severity of the attack. Cases that set in
with great violence after an incubation of two or three days or less are
likely to advance to an early death. An early generalization of the
spasms, with high temperature (104° F), hurried breathing, congestion of
the mucosæ and extreme excitability may end fatally in twenty-four hours
or within a week.
If on the other hand the incubation appears to have extended over one,
two or three weeks; if the disease is at first equivocal, with some
stiffness and firmness of the muscles, but with little or no trismus; if
the patient can open the jaws an inch or more and masticate even slowly
for a number of days after the onset of the first symptoms; if the haw
projects only slightly over the eyeball and the excitability is not
extreme the prospect for recovery is much better. Such tardy cases may
seem to stand still for a week and then have a slight aggravation and
this may be repeated, or a slow improvement may set in and go on
gradually to complete convalescence. Improvement may be manifested by a
softer or more relaxed condition of the muscles, by a slightly freer
movement of the limbs and jaws, by a greater ease in swallowing, by
encreasing movements of the ears and eyes, by the lessened projection of
the haw, by the freer breathing and circulation and by the permanent
lowering of temperature to the normal standard. Convalescence is always
slow, but especially slow in severe cases in which time must be allowed
for repair not only of the central nervous lesions but also of the
ruptures and trophic changes in the muscles.
In _cattle_ the disease is usually slow in its progress and improvement
may not set in till the close of the third week. In sheep, goats and
dogs on the other hand it is habitually acute, and death may supervene
from the third to the eighth day. In the horse all forms are met with
and the result will vary according to the severity of the attack.
_Mortality._ Friedberger and Fröhner sets the mortality in sheep and
pigs at nearly 100 per cent.: in horses at 75 to 85 per cent.: and in
cows at 70 to 80 per cent. In tetanus neonatorum in lambs, the deaths
reach about 100 per cent. In this case the disease usually sets in
within forty-eight hours after birth, and with a very high temperature
difficult deglutition becomes a marked feature, so that if the patient
is not speedily killed by dyspnœa, it soon perishes from starvation and
exhaustion.
The _cause of death_ is usually _asphyxia_, _hyperpyrexia_, or
_exhaustion_.
_Lesions._ There are no constant or pathognomonic structural changes in
tetanus. Those that are found are inconstant and as a rule secondary. A
wound (entrance channel) can usually be made out, often in the region of
the foot, or in connection with castration. In the new born there is the
unhealed navel, and in parturient cows the catarrhal, septic or injured
womb. In the seat of such wound may be found the foreign body (nail,
splinter, etc.), and some pus or simple congestion or even necrosis. The
nerve trunks leading from such infected wound may be hyperæmic. The
presence of the bacillus in the wound may be determined by microscopic
examination or inoculation on a small animal.
The changes in the nerve centres may be congestion of the horns of gray
matter, and there may be slight hæmorrhage, exudation, especially shown
in the encrease of the cerebro-spinal fluid, softening, cell
proliferation, and granular invasion of the nervous tissue. In separate
cases the myelon, the corpus striatum and the cerebellum have shown
lesions. The meninges are occasionally hyperæmic. Spinal lesions have
been noted especially in the bulbo-cervical and lumbar regions.
Exceptionally in the horse there are blood extravasations from fractures
or dislocations of the vertebræ.
In subjects dying of asphyxia the lungs and right heart are congested,
and the blood may be black, only loosely coagulable and with free
hæmoglobin. There is congestion of the intestinal as of the respiratory
mucosa, and also of the liver, spleen and kidneys. The congested bladder
usually contains urine contrary to what is the case in rabies.
_Diagnosis._ From _strychnia poisoning_ tetanus is distinguished by the
gradual and progressive approach of the spasms and by the absence of the
intervals of complete relaxation which separate the rapidly recurring
and violent spasms of strychnia. In tetanus the spasms may be modified
but never completely intermitted, and more or less stiffness, trismus
and protrusion of the haw constantly persist. In strychnia too, the
paroxysm is far more intense than in the early stages of tetanus. The
spasms of strychnia are general, while those of tetanus are often most
intense in particular groups of muscles often at first in the vicinity
of the inoculation wound.
From _rabies_, tetanus is easily distinguished by the absence of any
history of a bite; by the persistence of the tonic spasms especially of
the masseters and abdominal muscles during the intervals between the
more violent paroxysms (in rabies there is temporary complete
relaxation); by the absence of clonic spasms which alone occur in
rabies; by the absence of the paralysis which characterizes advanced
rabies; by the mental clearness and the absence of hallucinations or
mischievous disposition which are marked features of rabies; by the
absence of the depraved appetite of rabies; and by the fact that the
brain does not contain the infecting germ as is the case in rabies.
From _rheumatism of the neck_ (torticollis) tetanus is easily
distinguished by the permanent trismus which is not shown in rheumatism,
and by the fact that spasms are easily roused by any artificial
excitement, indicating an extraordinary hyperæsthesia and excitability
which are nearly absent in rheumatism. The steady unmistakable progress
of tetanus is in itself diagnostic.
From _meningitis_ tetanus is to be diagnosed by the presence of trismus
without impairment of the mental faculties or fever. In meningitis the
spasms are usually confined to particular groups of muscles and do not
become generalized under active excitement as in tetanus. Even if the
spasms of meningitis affect the jaws and pharynx they are rarely
paroxysmal or roused by excitement as in tetanus. They may even be
clonic.
_Tetany_ is more commonly localized in particular groups of muscles, and
shows longer and more irregular intervals between paroxysms than does
tetanus. It is improved by thyroid extract, and may be roused at will to
contraction by pressing on the nerve going to the affected muscles.
_Laminitis_ in its most violent form and early stages, may be confounded
at first glance with tetanus, but the high fever, the standing on the
heels, the advance of the hind legs under the body, the great heat and
tenderness of the feet, the impossibility of standing on one fore foot
when the other is lifted and the strong pulsation of the digital
arteries, are sufficiently distinctive.
_Treatment._ For fully developed tetanus no known resort of therapeutics
can be relied on. In slight cases that have shown a long incubation and
a slow increase and extension of spasm and in those having trismus only,
a recovery may be expected. Treatment has been conducted largely on
theoretic lines and may be divided into antispasmodic, eliminating and
antidotal or antiseptic.
Rest, darkness and absolute quiet are the first and main considerations.
A dark stall, with no straw litter, the rustling of which often excites
the patient, but rather a little chaff, saw dust or even earth to
prevent noise from the feet, and the exclusion of all visitors are
essential. As a rule slings should be put under the patient so that he
cannot lie, nor drop down, and this becomes more imperative as the
disease advances. The aggravation of the spasms when down, and the
danger of their extension to the respiratory muscles are far more to be
dreaded than the temporary excitement caused by the application of
slings. Food should be sloppy mashes, of bran, middlings, oat meal,
linseed meal, gruels or milk, or green food may be allowed in moderate
amount if the jaws are still movable. It must not be forgotten that
digestion is impaired and food that is indigestible, especially
fermentescible, or in excess, may arouse fatal colics and bloating, yet
in a protracted exhausting disease like tetanus, the strength must be
sustained by all means in our power. Pure water should always be
accessible. Food and water should be furnished in buckets at a level
which will not necessitate either raising or dropping the head to get to
them (about 4 feet). The food must be given often, in small quantity to
avoid fermentation and spoiling. If noise cannot be wholly excluded it
may be an advantage to put cotton wool in the ears. I have seen a mare
recover when completely covered with cotton wool under blanket and
hoods.
_Local antiseptic treatment._ Theoretically this is of great value since
the microbe is confined to the inoculation wound and by the time the
first symptoms appear, the spores have developed into bacilli and are in
a condition to be easily destroyed by disinfectants. We can, therefore,
by caustics or active disinfectants destroy the infecting microbian
colony, and prevent the further entrance of any toxins into the
circulation and nerve centres. The principle has been shown
experimentally successful in cases of inoculation in the tails of cats
and Guinea pigs, and the amputation of these members as soon as tetanic
symptoms appear (Kitasato, Babes). Unfortunately in too many cases, when
first seen, too much of the marvelously potent toxin has already reached
the nerve centres, and these have already undergone such changes, that
the disease is likely to go on to a fatal issue in spite of the cutting
off of future supplies of toxin. Yet the principle is sound and proves
helpful in proportion as it is applied nearer to the time of infection.
The most thorough method is the amputation of the infected member, if
like the tail or ear it can be excised without ruining the animal. In
1875, Barbillon had success in again amputating the tail, in a case of
tetanus after docking. Next to this comes the excision of the wounded
tissues, but this can too seldom be effectually and certainly
accomplished, and we must fall back on caustics and antiseptics. The
actual cautery if thoroughly applied may be trusted to destroy the
bacillus along with the tissues, but most of the chemical escharotics
unite with the albumen to form an impermeable film, which protects the
tissues in the deeper part of the wound against the antiseptic action.
Of the different antiseptic applications _carbolic acid_ should be
especially recommended as being not only antiseptic, but also an
antidote to the toxins as shown below. It has the further advantage of
acting as a local anæsthetic, and of not coagulating albumen. Creosote,
creolin, lysol or other antiseptic may be used instead and should be
applied thoroughly to all parts of the depth of the wound on a pledget
of surgeon’s cotton or through a tube. When agents so little destructive
are employed they may be continuously applied to the sores for a length
of time.
Recoveries have taken place after neurectomy, and after stretching the
nerve going to the wounded part, the theory being to check the afferent
(sensory) nervous current, and arrest the reflex spasms. The new
irritation, however, caused by the surgical wound is to be dealt with,
and may itself turn the balance against recovery.
Nervous derivation appears to have been beneficial in some advanced, or
partially convalescent cases. One horse after 14 days illness (Taffanel)
and another after 21 days (Prud’homme), were castrated, bled freely and
slowly recovered. Tisserand gives another case without mentioning the
stage of the disease. A horse with advanced tetanus was taken to the
seashore and shot. He fell into deep water, swam ashore and made a
recovery. But whatever virtue may be in elimination of the toxins by
bleeding, in nervous derivation or in the shocking of an unbalanced
nervous system, these can hardly be recommended as regular methods of
treatment. Yet the older veterinary records contain many instances of
alleged benefit from bleeding.
_Internal treatment._ The whole list of antispasmodics have been tried,
with no very satisfactory result. Opium has been extensively employed in
spite of its tendency to encrease constipation, and morphia given
hypodermically has checked spasm and induced sleep. Hydrocyanic acid and
potassium cyanide have shown a decided reducing action on the spasms
with the same drawback of favoring constipation. Potassium and other
bromides are useful in mild and chronic cases, and may be given in full
doses in combination with chloral hydrate. Calabar bean and eserine have
been given for their physiological action on the nerve centres, and
recoveries have followed their use, but they have little effect on the
spasms until the system has been saturated to the point of threatening
collapse. Chloroform has the advantage that it can be easily given by
inhalation, but while it may be pushed to the extent of temporarily
checking the spasms, yet these return at once when the action of the
drug is exhausted. Chloroform is always dangerous to a weak or exhausted
heart and cannot be given for any great length of time continuously. It
is, therefore, very unsatisfactory. Sulphonal and trional have similarly
checked the spasms. Gelsemium has given good results in certain mild
cases, but it must be pushed to the extent of coming just short of
poisonous doses, and the fear of an overdose, together with its failure
in severe cases, have prevented its general acceptance. The same end has
been sought by the use of nauseating antispasmodic agents, as tartar
emetic, tobacco, apomorphia, and lobelia, but though useful in
individual cases, these are on the whole no more successful than other
agents. Phenacetin, antipyrin, acetanilid and cocaine have respectively
received credit for some recoveries.
Chloral hydrate commends itself as being at once a most potent
antispasmodic and hypnotic, and an antiseptic. It can, moreover, be
conveniently given as a rectal injection, thus avoiding the irritation
and excitement of administration by the mouth. Given in this way too, it
tends to relaxation of the bowels, instead of constipation. Carbolic
acid which can be conveniently given by enemata has an anæsthetic
action.
_Antiseptic and Antidotal_ or _Antitoxin treatment_ is more promising,
yet it has failed to come up to the full measure of expectation, mainly
because the nervous changes have already reached a stage which cannot be
undone speedily or at all. Under this heading would come phenic acid (½
oz.) and probably chloral hydrate (1 oz.), already referred to, and the
various compounds of iodine which may be here noted.
_Iodine Terchloride._ _Iodine._ Behring and Kitasato secured immunity of
two months duration, by injecting the animal with a filtrate of a
culture of tetanus bacillus, and then injecting at the same point 3cc.
daily, for five days, of a 1 per cent solution of iodine terchloride.
Roux and Chamberland had similar results by using iodine instead of the
iodine terchloride, and maintained the full measure of immunity by
repeating the inoculation every fortnight. Here it is evident that the
action of the iodine is directly antitoxic or antidotal, when introduced
along with the toxins and before they can reach the nerve centres.
_Iodide of Potassium._ In an experimental case of general tetanus in the
dog, Babes had a recovery in ten days, by injecting subcutem 5cc. of
Lugol’s solution and thereafter for eight days 10 to 30cc. daily. This
suggests the use of this agent along with phenic acid, or as an
alternate, in any case in which phenol appears to be losing its effect
by use. It may be used hypodermically, or in the drinking water or by
rectal injection. It has an advantage over phenic acid in being actively
diuretic and eliminating, while phenic acid has the recommendation that
it tends to lower nervous excitability and moderate the reflex spasm.
Theoretically the combination of the two agents, which do not mutually
decompose each other, should give the best results.
These experiments have been often repeated showing clearly the antidotal
action of the iodine compounds when mixed with the virus before
inoculation, or injected with the virus into the seat of the wound. When
employed later when the symptoms have developed, everything depends on
the changes already accomplished in the nerve centres, and the severity
and generalization of the spasms.
_Serum Antitoxin Orrotherapy._ Babes appears to have been the first
(1889) to use the serum of animals (rat) recovered from tetanus in
mitigating and curing tetanus in experimental cases. An attempt on a
well developed case in man failed. His method of preparing the serum is
as follows: A horse of 900 lbs. (461 kgm.), is inoculated with a mixture
composed of 0.5cc. toxin (of which 0.001 mgm. kills a mouse) and 0.5cc.
iodo-potassium iodide, and then at intervals of four or five days of
2.5cc., 4, 5 and 10cc. of the iodine mixture. Then stronger mixtures are
used: first 2 parts of toxin to 1 part of the iodine mixture; dose
10cc.; then 3:1 dose 10cc.; then 4:1 dose 5cc.; then 15:1 dose 10cc.;
then 30:1 dose 25cc.; and finally virulent cultures in progressively
encreasing doses 10, 20, 30 and 50cc. One week after the last injection
1cc. of the blood serum will antidote 50cc. of toxin. Injection of toxin
is however continued and the dose is gradually raised to 200cc. Eight or
fourteen days after the last injection the blood serum may be taken for
protective purposes. He has prepared antitoxin from cows in the same
way, and Brieger and Ehrlich have prepared it from the goat. Chickens
being naturally refractory to tetanus toxin can bear large doses and a
potent antitoxin is more speedily secured from them. In the case of the
cow the milk is rich in antitoxin.
Other methods of preparing an animal for producing the antitoxin have
been resorted to as injecting it with a mixture of toxin and antitoxin
in increasing doses, or again injecting with a mixture of toxin and
thyroid extract in increasing doses. The extract of the normal thyroid
contains a natural antitoxin.
It may be fairly inferred that the antitoxin is not formed in the nerve
cells alone in their resistance to the toxin, but also in the thyroid,
the liver (bile having an antitoxic action), and perhaps in other organs
or liquids.
The blood of the immunized animal drawn through the sterilized cannula
and aspirating syringe is coagulated in vessels set on ice, and the
serum when separated is mixed with 0.5 per cent. carbolic acid and 1 per
cent. chloroform, and kept in the dark in well closed bottles. It will
usually keep for years.
Early experiments with antitoxins showed that when mixed with the toxin
before injection it could be trusted to neutralize it. Ehrlich, Tizzoni
and Cattani even claimed success in all experimental subjects if
employed as soon as the slightest symptoms of tetanus were shown. They
found, however, that it required 1000 to 2000 times the amount of
antitoxin in such cases than was required when it was mixed with the
toxin prior to injection. They found, moreover, that when the disease is
fully developed the dose must be 150 times more than is required when
the first symptoms are shown. It should be added that when the disease
has developed rapidly, after a short incubation, and is well advanced
the antitoxin treatment is usually of little avail. The changes in the
nerve centres are already too great to allow hope of recovery. In man
the ratio of recoveries are about as follows: After incubation of 10
days or under, 3 to 4.5 per cent. recover. After an incubation of 11 to
15 days 50 per cent. recover (Woodhead). Lambert claims 46 per cent.
recoveries in 114 cases, and 38.71 per cent. recoveries in acute cases
with an incubation of 8 days and under.
On the whole the ratio of recoveries is greater under the antitoxin
treatment than before, though far from sustaining the optimistic views
of Behring and other early experimenters. Babes draws attention to the
fact that spore laden splinters of wood, in the wound render the
antitoxin useless as a continuous succession of fresh spores, bacilli
and toxins are thereby supplied. As this is one of the most common forms
of casual infection it interferes seriously with the success of
antitoxin treatment.
Roux and Borrel found that in animals, intracranial injection of the
antitoxin was the most effective method. Recovery also followed its
injection into the cerebrum of a tetanic boy. Babes had recoveries in
two cases out of three with cerebral or intracranial injections. As the
reflex spasms depend on the spinal centres these would seem to be the
ideal points of injection.
Babes who has done a large amount of subcutaneous and intraperitoneal
injection of antitoxin, employed for man doses of 300 to 500cc., which
would represent 8 to 10 ozs. as the dose for an ordinary horse. As the
antitoxin is rapidly eliminated from the body, these should be repeated
daily or every other day. Nor should this supercede other curative
measures. The leading principles may be thus stated: 1st. Antitoxin
should be used at the earliest possible moment. 2nd. The infected wound
area must be thoroughly disinfected or destroyed by caustics, and that
at once. 3rd. The antidotal treatment by phenol and iodine must not be
omitted. 4th. Palliative treatment by antispasmodics, narcotics or
soporifics must go hand in hand with antitoxic treatment. 5th. Measures
should be taken to secure elimination of the toxins present in the
blood.
_Treatment by brain emulsion._ Wassermann and Takaki (Berlin Klin. Woch.
Jan. 3d, 1898) have in a number of cases, mixed 1cc. of brain substance
of a warm-blooded animal with ten times the lethal dose of tetanus toxin
and injected without producing any symptoms of tetanus. They obtained a
similar immunity by injecting the brain emulsion 24 hours after the
injection of three times, and in other cases of five times the lethal
dose of tetanus toxin. Control cases uniformly died of tetanus. The
brain matter was obtained from Guinea pigs, pigeons, rabbits, horses,
and men. They accordingly advanced the theory that brain matter is a
direct antidote to the tetanus toxin, uniting with it chemically and
rendering it innocuous. The liver, spleen, kidney, bone marrow and blood
serum gave no such protection.
Marie, in a series of experiments, injected the brain emulsion and
tetanus poison at different parts of the body of Guinea pigs and found
that fatal tetanus ensued. It would appear, therefore, that the brain
emulsion acts by direct contact, and that it is only by its meeting and
combining with the toxin before the latter reaches the spinal cord that
tetanus can be prevented.
Roux and Borrel (Ann. de l’Instit. Pasteur, 1898) demonstrated this
union between the poison and brain matter, by making an emulsion of the
two, and putting in a centrifuge, which will separate the brain
substance from the clear liquid. The fluid obtained in this way was
shown by injection on the living animal to contain almost no toxin.
Knorr and Blumenthal reached the same conclusion as to a chemical union
with the brain matter which robbed the toxin of its toxicity.
Knorr, and Tizzoni, and Cattani and Morax showed indeed, that if the
tetanus toxin is injected subdurally or into the surface layers of the
cerebrum, it produces not tetanus, but a characteristic cerebral
disease. A dose of ¹⁄₂₀th or ⅒th cc. of tetanus toxin produces in the
rabbit, in 10 to 12 hours, restlessness, constant change of place, and
signs of great fear like hiding the head, turning rapidly round,
attempting to escape, polyuria, grinding the teeth, epileptoid
convulsions. The toxin in this case had manifestly united with the brain
substance while the cord suffered little.
Metchnikoff (Ann. de l’Inst. Past., April, 1898) holds that the brain
matter is only valuable in holding the toxin until it can be destroyed
by the leucocytes. He showed that the injection of the tetanus toxin in
chickens or Guinea pigs greatly encreased the production of leucocytes.
He injected tetanus toxin into the aqueous humor of the rabbit without
producing much effect, but when the same agent mixed with cerebral
substance was injected, the result was a great accumulation of
leucocytes, and hypopion. If the mixture of brain substance and tetanus
toxins were injected on the brain, little encrease of leucocytes
occurred, but if thrown into the peritoneum, a most remarkable
leucocytosis took place. In twenty minutes after the injection the fluid
withdrawn from the abdomen showed large numbers of leucocytes filled
with brain substance, but no free cerebral matter.
The present status of the treatment by brain substance is therefore
somewhat uncertain. The value of that agent in holding the toxin is
allowed, but like the antitoxin it must be employed before the toxin has
reached the nerve centres and united with the living ganglion cells. Its
use would be called for therefore at the earliest possible moment and it
should be continued so long as there is reason to suspect the production
of fresh toxin in the wound. Its direct action on the toxin would
suggest its injection around an infected wound, or even as a dressing
for the wound in connection with antiseptics. When tetanus has already
set in it cannot be expected to undo the evil already accomplished by
the union of the toxin with the cells of the cord, though it might in
part arrest and hold new supplies of this poison coming from the wound
to the nerve centres.
_Prevention._ In a disease so deadly as tetanus and so refractory to
treatment even by antitoxin when it is once developed, prophylactic
measures are of the greatest importance. With the extensive adoption of
antiseptic surgery there has already been a material diminution in the
number of cases, yet a greater attention is demanded to the prevention
of casual cases which result from ordinary wounds. Dirty, grimy wounds
filled with the dust of stable yard or garden soil, and such as contain
splinters of wood, stones, thorns, straw and the like can only be
considered quite safe after thorough disinfection. It has been shown
that the toxin is easily neutralized at the time of infection, whereas,
after the disease is developed it will require 1,000 or 100,000 times as
much antitoxin to produce the same effect. In the case of soiled wounds,
therefore, in a valuable animal, a harmless injection of antitoxin or of
phenic acid or iodine solution before the development of tetanic
symptoms is not an unwise precaution. A succession of such injections
might be given to ward off the disease until after a lapse of time
exceeding the short and dangerous incubation.
Much more important is the disinfection of the wound itself. All foreign
bodies must be removed, but especially those that like splinters of wood
and straws are likely to harbor the spores of the bacillus. Then the
wound may be thoroughly cauterized thermically or chemically, or it may
be irrigated with a strong antiseptic solution and then dressed with
some agent that will prove destructive to the spores, and antidotal to
the toxin. Strong carbolic acid may be applied to the whole raw surface
including the uttermost recesses of the wound, and after a few seconds
or half a minute this may be neutralized by filling the wound with
dilute acetic acid or alcohol, after which a dressing of Lugol’s
solution may be applied. Lambert advises a combination of hydrochloric
and carbolic acids.
Weaker antiseptics, like a 5 per cent. solution of carbolic acid, do
more harm than good, as they destroy the pus and saprophytic microbes
and even the tetanus bacillus in the wound, without affecting the
tetanus spores, which finding no other microbes to contest with them the
possession of the field may find themselves in a better position than
before to develop into bacilli and cause tetanus.
Tetanus neonatorum may be certainly prevented by the application of a
disinfectant plaster on the navel at birth. Over 50 years ago in
Scotland this desideratum was met by applying on the navel of the
new-born child a soft and immaculately clean piece of cotton cloth which
had just been flamed over a light. On the island of St. Kilda the former
mortality of 67.2 per cent. of new-born infants, was promptly abolished
by dressing the navel daily with iodoform. For new-born animals a cheap
and convenient application may be made by incorporating 1 oz. powdered
iodine and 2 lbs. wood tar, and smearing this on the navel.
Much may be done by disinfection of stables and yards where the victims
of tetanus have been. The anærobic germ soon loses its virulence in free
air and sunshine, and one has to dread especially, filthy stables,
collections of manure, contaminated litter, wood, combs, brushes and
buckets. In unpaved yards remove the infected surface soil and replace
by fresh disinfected earth, or still better, well burned brick.
For horses which are necessarily exposed to manure or contaminated soil,
it is commendable to wash the hoofs and pasterns on returning from work
and then sponge with a weak solution (5 per cent.) of phenic acid.
Another resort is to smear the hoofs daily with an ointment of tar and
lard, equal parts. This cannot protect from infection by splinters of
wood containing the spores, but is to a large extent preventive in the
case of bacilli that might have been otherwise lodged on the surface and
which could have been carried into the wounds inflicted by nails and
other noninfected bodies. Careful shoeing is all important, to avoid the
bruises, suppurating corns and _gravelling_ which make openings for the
ready entrance of the spore.
Roux and Nocard recommend immunization by protective inoculation. This
is not only possible, but would be justified economically in the case of
valuable animals, or in all animals in a district where the bacillus
tetani is universally spread. The method is the same as advised above
for the immunization of animals, for the production of antitoxin.
In districts where tetanus is rare, the cost of universal immunization
against the disease would very far exceed the losses front casual cases.
Under such conditions it would be an economical blunder.