greater proportion of the ferments above mentioned. The milk is heated
at atmospheric pressure, and is kept for a time at a temperature of
between 150° and 157° Fahr. (65° and 70° C.). It preserves its
properties and composition, but sterilisation is not complete, and the
milk cannot be kept indefinitely.
_Concentrated Milk._—Concentrated milk is obtained by prolonged heating
to 157° Fahr. (70° C.) in a vacuum, when it becomes syrupy by
evaporation and its composition is not greatly modified. It is then
drawn off into bottles, which are hermetically sealed and subjected to a
higher temperature to complete the destruction of all the germs.
Condensed milk keeps for a very long time. To prepare it for use it is
mixed with a certain quantity of water, and then yields a liquid similar
to normal milk.
_Sterilisation._—Sterilisation necessitates the use of special apparatus
in which the milk is heated in a water or steam bath sheltered from the
action of the air, the temperature rising to 212° to 240° Fahr. (100° to
115° C.); all the ferments are destroyed, and the milk will keep
indefinitely, but its composition is slightly modified.
=Diseases Transmissible to Man through the Medium of
Milk.=—_Tuberculosis._—The history of tuberculosis contains numerous
facts proving the possibility of contagion by milk from cows suffering
from tuberculous mammitis, though it seems necessary that the milk
should be taken for a certain time to produce these effects.
_Foot-and-Mouth Disease._—Observations recorded by veterinary surgeons
prove that this disease affects the teats. It may be transmitted to man.
The milker may be directly inoculated, but the milk is the ordinary
vehicle of contagion. Chauveau saw an epidemic in a school at Lyons
where milk was obtained from cows suffering from foot-and-mouth disease.
In a similar way 205 persons were inoculated at Dover in 1884, and
suffered from vesicles about the mouth.
Although foot-and-mouth disease is extremely benign in men, it is well
to take every precaution against it.
_Gastro-Intestinal Infections._—Cases have been recorded of
gastro-intestinal infection in young animals and children in consequence
of consuming milk which had undergone abnormal changes. Milk containing
various kinds of microorganisms may at first produce lactic indigestion
and afterwards diarrhœic enteritis.
CHAPTER VII.
MALE GENITAL ORGANS.
The scrotum, the vaginal sheath, the testicles, the vas deferens, the
vesiculæ seminales, the prostate, and Cowper’s glands may all become the
seat of disease.
The scrotum and testicles seldom reveal more than mechanical injuries of
external origin, producing wounds and cuts and, in the case of severe
contusions, hæmatoma of the scrotum, of the vaginal sheath, and of the
testicles. Inflammation of the testicle, that is to say, traumatic
orchitis, is rare; on the other hand, Moussu has several times seen
tuberculous orchitis, for which he has operated. This, however, was in
the boar. These different lesions, the last named excepted, usually heal
with rest and the application of antiseptic dressings, anodyne and
resolvent lotions.
Breeders seldom retain more entire animals than are strictly necessary
for reproduction. The others are castrated, and this alone explains why
the treatment of genital diseases in male animals of any species is
rare.
TUMOURS OF THE TESTICLE.
Of the genital diseases which possess real clinical interest the most
important are tumours of the testicle. These occur not only in male
animals, but also in those which have undergone the operation of
bistournage.
It might _à priori_ be believed that in an animal of the latter class
the testicle had been completely destroyed, not only from the physical,
but from the pathological point of view. This, however, is by no means
the case, and Cruzel has described, under the erroneous designation of
sarcocele, tumours of the testicle which develop in oxen of various
ages.
Moussu has had a similar experience with animals of from four to six
years of age which had been carefully operated on.
These tumours, the origin of which is unknown, develop at the expense of
the rudiments of the atrophied testicle. They vary in character, and
Moussu has only observed tumours of a type different from that of the
testicle itself, containing tracts of carcinomatous, sarcomatous, and
fibrous tissue. They also appear to vary greatly in gravity, for,
although the cases seen by Moussu had become generalised in a few
months, Cruzel states that these tumours may remain stationary for
several years.
[Illustration: $1]
=The symptoms= consist in progressive enlargement of the scrotal region
and the appearance of a tumour surrounded by œdematous or lardaceous
tissue.
The tumour, which is confined to one side, increases in size, is
bosselated and adherent at points to the surface of the skin, while it
is insensitive or only slightly painful to the touch.
In a few months it may increase to the size of a child’s head. The
animals have difficulty in moving or lying down, the hind limb on the
affected side is abducted, and the animal usually lies on its chest and
abdomen. The patient rapidly loses flesh, although the appetite remains
good.
When the growth is removed, it is easy to prove that the tumour has
developed in the atrophied mass of testicular tissue, and that it
remains suspended from the end of the cord.
=The diagnosis= of tumour of the testicle is extremely easy, for the
condition cannot be mistaken for a hæmatoma or for a scrotal abscess.
=The prognosis= necessarily depends on the nature of the tumour, but as
it is impossible to determine this point before extirpation, the
prognosis should always be regarded as very grave.
=Treatment.= Whatever the nature of the tumour, ablation is advisable.
If it is of a benign character, recovery may be complete and permanent,
but if it is malignant, generalisation will rapidly ensue. Before
interfering surgically, however, it is essential to examine the
inguinal, pelvic, and sublumbar lymphatic glands, to make sure that they
are not affected. If they prove to be already invaded, an operation
should be avoided.
[Illustration: $1]
Even despite such precautions and the apparent absence of any glandular
infection, operation may be followed by generalisation in a few months,
although for a short time the condition may seem to have greatly
improved. No special indications need be given beyond those suggested as
necessary in dealing with all kinds of tumours, whatever their nature.
The skin should be freely divided, that the tumour may be thoroughly
dissected out and no fragments be overlooked. The mass of the tumour
having been dissected free, the _écraseur_ is applied to the pedicle or
the cord. Enucleation of the tumour may be very difficult on account of
the presence of numerous ramifications or attachments, but the closest
attention must be given to removing every fragment if a fresh local
growth is to be avoided. In the event of fragments being left, a fresh
growth is certain to occur.
Generalisation, which may extend to all the viscera (lymphatic glands,
liver, spleen, lungs, pleura, peritoneum, heart, etc.), is indicated by
rapid wasting, fever, acceleration of breathing, digestive disturbance,
and sometimes coughing, etc.
Local new growths assume the form of ulcerating swellings. In practice,
if the general condition can be improved for a short time, it is
advisable to slaughter the animal.
ACCESSORY GLANDS OF THE GENITAL APPARATUS.
(PROSTATE, VESICULAR SEMINALES, COWPER’S GLANDS.)
Inflammatory or other diseases of the above glands are most frequent in
entire animals. As a group they are uncommon, and are still
ill-recognised and ill-described, being seldom identified except on
post-mortem examination.
[Illustration: $1]
The cause of inflammation of the prostate, of the vesiculæ seminales,
and of Cowper’s glands is probably an ascending infection of the urethra
and neighbouring channels, a fact which explains the comparative rarity
of such conditions in castrated animals.
The pathogenic germs penetrate from the urethra into the excretory ducts
of the glands, obtain a lodgment in the culs-de-sac of the glands
themselves, and thus produce simple or suppurative inflammation.
=The symptoms= may easily be mistaken, to some extent at least, for
those of acute cystitis or cystitis due to the presence of a calculus,
and it is only by rectal examination that the diagnosis can be made.
The first symptom is defective micturition, which occurs in jets, is
intermittent and painful, and sometimes causes slight groaning. It is
accompanied by vesical colic, spasmodic lifting of the hind legs, and
more or less unsuccessful expulsive efforts.
These symptoms are of reflex or mechanical origin, and are due either to
direct compression of the urethra by an hypertrophied and inflamed
gland, or to spasm of the vesical sphincter. The urine passed, unlike
that in cases of acute cystitis or in cystitis due to calculus, is of a
normal character. Rectal examination usually reveals distention of the
bladder, and hypertrophy and exceptional sensitiveness at certain
points.
If the painful and hypertrophied area is over the neck of the bladder,
this indicates that the lobes of the prostate are affected. If, however,
the affected parts are situated on the sides of the neck and along the
posterior pointed end of the bladder (Fig. 239), the vesiculæ seminales
are affected; finally, if the painful points are directly above the
ischial arch and below the sphincter ani, Cowper’s glands are the seat
of disease (Fig. 240).
To diagnose these conditions requires very close and careful
examination. They may easily be mistaken for acute cystitis, though the
character of the urine should suggest doubts and lead to rectal
examination.
Although they do not endanger the animal’s life, these conditions give
rise to such serious inconvenience as often to render entire animals
useless for stud purposes.
Local =treatment= is impossible, and the practitioner is restricted to
the use of anodynes, balsamic preparations and diuretics. The treatment,
in fact, differs little from that of cystitis. In cases of suppuration
of Cowper’s glands, the abscess usually forms just below the anus and
close to the median line. Thus the diagnosis may be confirmed by
capillary puncture, the part being laid open if necessary.
SECTION VIII.
DISEASES OF THE SKIN AND SUBCUTANEOUS CONNECTIVE TISSUE.
CHAPTER I.
ECZEMA.
Under the name of eczema may be grouped a series of cutaneous diseases
characterised by pruritus, by a discharge from the skin, or simply by
epidermic proliferation, without any apparent parasitic or accidental
cause.
These diseases have been referred to a special constitutional condition
termed a diathesis, although during the last few years we have come to
recognise certain microbic and toxic influences in their production. In
the ox eczema assumes different appearances. Accordingly, the disease
has been divided into the acute, chronic, sebaceous, and toxic forms.
ACUTE ECZEMA.
=Causation.= In the ox, as in all other species, the determining cause
is to be found in bad hygienic conditions, improper feeding, and in a
special individual condition of the animal affected, that is to say, a
diathesis.
=Symptoms.= During a preliminary period, which might be termed a
prodromic period, only general symptoms can be detected, such as fever,
loss of appetite, digestive disturbance, constipation, etc. Local signs
are still absent, or at least are not noticeable, and are only
represented by congestion of the skin.
The second phase is characterised by a papulous eruption which is
difficult to detect, inasmuch as it occurs in the depths of the coat.
Nevertheless, the skin is distinctly sensitive, and at numerous small
points the hairs appear to stand upright.
The third phase consists in the development of more or less confluent
vesicles, with exudation and discharge. The disease is not really
visible externally until after the hair has become agglutinated by the
discharge. This discharge is seldom as abundant as in eczema in the dog
or horse. It is produced slowly and dries rapidly.
As the crusts fall, carrying with them a portion of the hair, the
general symptoms disappear, but the sites of these vesicular patches now
show cracks extending as deep as the dermis and often complicated by
secondary infection involving suppuration, adenitis, abscess formation,
or diffuse subcutaneous suppuration.
Acute eczema is generally confined to the limbs. It may develop fully in
from twenty-four to forty-eight hours. The acute stage is attained in a
few days, and the condition disappears in two to three weeks provided it
does not assume the chronic form as the result of complications.
=Diagnosis.= The absence of parasites enables the condition to be
distinguished from phthiriasis and acariasis, whilst the history
prevents its being confounded with toxic eczema.
=Prognosis.= The condition is troublesome rather than grave. Suppuration
is often persistent, and despite careful attention the discharge may
only diminish slowly, while the disease is always liable to return.
=The treatment= is local and general. Local treatment consists in
emollient and antiseptic washes and the application of drying powders.
The former comprise glycerole of starch, bran water, boric ointments,
camphorated vaseline, iodine and glycerine. At a later stage the skin
can be washed with decoction of oak bark or a weak iodine solution,
followed by the application of talc or starch powder. As far as possible
this external treatment should be supplemented by the frequent use of
mild purgatives and various diuretics, which seem to have a special
action on the arthritic diathesis.
CHRONIC ECZEMA.
Comparatively few cases of chronic eczema have hitherto been described
in oxen, and the details given are extremely meagre. Chronic eczema may
assume that form from the first or may succeed acute eczema. The causes
are probably the same in both conditions.
=The symptoms= appear to be those of the acute form, but are much less
severe. They consist in papulation, a miliary vesicular eruption,
pruritus, and the formation of crusts and epidermic scales.
In a case seen by Mégnin the crusts separated and fell away, leaving
bare spots. The disease re-appeared for several years in succession. The
spots finally remained bare, but showed no thickening of the skin and no
microscopic changes.
=Diagnosis.= Microscopical examination is necessary to distinguish this
disease from scabies or ringworm.
=The prognosis= is grave, because large areas of the skin may be invaded
in succession.
=Treatment.= As in acute eczema, the condition is improved by the
prolonged administration of small doses of salines and diuretics.
Arsenical preparations are also valuable, but should only be employed
for two or three weeks together, with intervals of equal duration. The
dangerous complications which sometimes result from accumulations of
this drug in the system are thus avoided.
SEBACEOUS OR SEBORRHŒIC ECZEMA.
Whilst the two preceding forms of eczema result from vascular
disturbance of the skin or dermis that now under consideration seems due
to vascular and secretory troubles in the accessory structures of the
skin, and more particularly in the sebaceous glands.
[Illustration: $1]
=Symptoms.= The disease develops slowly. At first circular or elliptical
patches of skin, distributed regularly over the body, more especially
round the natural orifices, become deprived of hair. The surface of
these patches is covered either with thick crusts of a peculiar
greyish-brown tint which display numerous superficial cracks, or parts
normally free from hair exhibit shining epidermic crusts arranged in
layers, which are shed on the slightest touch.
This depilation has a strong tendency to spread, and so at first it
often resembles ringworm. It results from changes in the hair follicles,
with atrophy of the papillæ and complete loss of hair. The changes in
the skin, however, are little marked. The skin itself is but slightly
thickened and preserves its usual suppleness, while the subcutaneous
tissue is not œdematous.
[Illustration: $1]
[Illustration: $1]
The hairs, however, when examined microscopically are found to be
thickened at their roots, though otherwise throughout their whole length
they remain normal. The condition is a consequence of disturbance in the
circulation and nutrition of the papilla and the root of the hair.
Finally, the congestive process extends to the sebaceous glands, the
secretion of which it modifies, and sets up seborrhœa, which is
responsible for the formation of the crusts and epidermic scales
above-mentioned.
The pathogeny of the disease is difficult to explain, but the stages in
the clinical development are as follows: the skin undergoes repeated
attacks of congestion, followed by seborrhœic folliculitis, epidermitis
and loss of hair.
=The diagnosis= is easy, the absence of ringworm being proved by the
absence of the spores of trichophyton and by the non-contagious
character of the discharge.
=The prognosis= is not grave from the point of view of general health,
the chief functions being perfectly regular, but it is otherwise as
regards possible terminations, viz., partial or total loss of the coat,
which may be irremediable.
=Treatment.= It is difficult to lay down a really satisfactory method of
treatment, because the exact cause of seborrhœa is still unknown. As it
is probably to be sought in some individual constitutional peculiarity,
the feeding and method of life should be changed and the skin stimulated
by washing with lukewarm water and soap and by dry friction. Locally, if
the alopecia threatens to be permanent stimulating applications may be
tried. These comprise lotions containing alcohol, solutions of chloral,
salicylate of soda, etc., and they should be applied with smart
friction.
The sufferers should not be used for breeding purposes.
ECZEMA DUE TO FEEDING WITH POTATO PULP.
Among the forms of eczema due to toxins, several varieties may be
recognised. Some result from the administration of drugs such as iodine,
others from special forms of food. The only one of clinical importance
is that following the consumption of excessive quantities of potato
pulp.
=Causation.= The disease is seen in all districts in which potatoes are
employed for the manufacture of alcohol and starch, more especially in
Germany. The disease seems to be a direct consequence of feeding with
residual products of distilleries and starch manufactories.
Spinola states that 160 lbs. of potato refuse per day to 1,000 lbs. of
body weight would certainly produce eczema: 60 to 80 lbs. only produce
it in rare cases and 20 to 40 lbs. are harmless.
There is a further point to consider as regards the variation of potato
pulp in toxicity. Potatoes yield a more or less active residue,
according to the year in which they are grown, their state of
germination, and the variety to which they belong. Raw or cooked
potatoes may produce eczema if given in large quantities or for long
periods.
Numerous theories have been advanced as to the nature of the morbid
disturbance producing eczema. Some authorities declare the appearance of
the disease to be due to the presence of a toxic principle contained in
potatoes, viz., solanin. It might be objected that this chemical
principle only exists during germination while potatoes that have not
undergone germination produce the disease. Further, the symptoms of
poisoning by solanin differ from those of this form of eczema, among
which loss of appetite, for instance, or stupefaction, or narcosis is
never observable.
According to other writers eczema is due to the action of the lower
alcohols contained in the refuse pulp, but again these properties exist
in brewers’ and distillers’ grains, the consumption of which produces no
bad results. Similar objections might be made regarding the suggested
action of the acids of fermentation (lactic, butyric, and acetic acids,
etc.).
Johne blames the salts of potassium, which, however, can only act as
digestive irritants, and Zürn suggests mycosic inflammation.
Whatever the toxic principle, its effects are most marked in animals
undergoing fattening, and are rarely found in working oxen, still more
rarely in milch cows. In the last named the injurious principle appears
to be eliminated in the milk, and this theory is supported by the fact
that the liquid has purgative properties; the calves which consume it
suffer from diarrhœa, which ceases when the feeding is altered.
Finally, it has been proved that different animals show different
degrees of susceptibility to the action of potato pulp.
=The symptoms= do not appear until after two or three weeks’ feeding on
the potato pulp. Then the animals walk stiffly, rise with difficulty,
and display redness, swelling and sensitiveness of the limbs. When the
œdematous infiltration and reddening have become distinctly marked there
appear, not only between the claws, as in foot-and-mouth disease, but
over the entire limb and principally near the folds of skin about the
joints, numerous closely-packed small papules, which in one or two days
become transformed into vesicles through exudation below the epidermis.
This marks the eczematous phase properly so called. The vesicles then
become ruptured, the exuded matter glues the hairs together, dries, and
forms crusts, which have a peculiar and distinctive odour.
The disease may extend towards the hocks, the knees, the stifle, the
armpit, etc. In the folds of skin surrounding the joints deep cracks
form, and sometimes become secondarily infected, thus leading to the
development of lymphangitis.
General symptoms, such as fever, loss of appetite and constipation,
always follow; they are afterwards succeeded by diarrhœa and progressive
weakness, ending in death.
The disease is easily curable if seen in its earlier stages, but after
all signs of the first attack have disappeared, the condition may return
five or six times in a year if potato pulp is again given. Recovery is
always very difficult in aged or enfeebled patients.
The mortality varies greatly; formerly it was as high as 20 per cent.,
but at the present time it is much lower.
=Diagnosis.= Provided the history of the case is borne in mind, the
diagnosis is always easy.
=The prognosis= is not grave if the disease is treated early.
=Treatment.= This consists first of all in altering the diet and
reducing the quantity of potato pulp, or, better still, in discontinuing
it entirely. The food should consist of good hay, bran, oatmeal gruel,
pollard, etc. Internally, diuretics are given to assist in the
elimination of the toxic products.
This treatment arrests the course of the disease. Suitable local
treatment will remove the existing lesions. It is precisely similar in
character to that of acute eczema, but it must be borne in mind that it
can only prove effective if the primary cause be removed.
IMPETIGO IN THE PIG.
The term impetigo is used to describe a disease characterised by an
eruption of papules, the discharge from which forms yellowish crusts,
which when dry are of a grey or brown colour. The point of origin of the
eruption is unknown, but the crusts rapidly become infected on contact
with the air, and the bodily lesions may end in suppuration. The disease
is not frequent nowadays except in sucking pigs and in large or
badly-kept piggeries.
=Symptoms.= The eruption usually appears between the ages of two and
three months, and is accompanied from the first by moderate pruritus.
The papules rupture after two or three days and discharge a
lemon-coloured liquid, which is distributed over the surface, dries
rapidly, and causes the bristles to stick together at the roots. The
crusts formed in this way remain adherent to the skin, though their
surface becomes cracked. They increase in thickness, cover the head and
part of the body, particularly the belly and the inner surface of the
thighs, and if removed, an operation of some difficulty, leave exposed a
bleeding, sanious, or purulent wound. The animals lose condition and
appetite, cease to grow, seem as though attacked with rachitis, and may
die if the general conditions of their maintenance are not improved.
The =diagnosis= is not difficult, but the =prognosis= depends on how
long the disease has existed and the bodily condition of the patients.
=The treatment= consists entirely in improving the hygienic conditions
and the feeding. The patients must be repeatedly washed or bathed and
carefully disinfected, and they must have better food.
The crusts should be softened before the animals are washed, so that
bleeding may be avoided and the affected areas not be transformed into
suppurating wounds. By applying oil or some fatty matter to the crusts
it is possible to cleanse the parts with bran water. If considered
necessary, this cleansing can be followed by dressing with boric or weak
creolin solution. Open-air life and good food soon relieve the principal
symptoms.
ACNE IN SHEEP.
Acne, that is to say, localised inflammation of the sebaceous glands and
hair follicles, sometimes occurs in sheep apart from any parasitic
invasion. The eruption is particularly seen after shearing, and it is
probable that, as in the horse, irritation produced by the machine, and
possibly by accidental infection, constitute the principal determining
causes.
=Symptoms.= The disease is indicated by the appearance of cutaneous
pustules, which are only slightly painful on pressure and which involve
the entire thickness of the skin. The dermis is hardly congested, and no
constitutional disturbance occurs.
Acne lesions may be more or less confluent, and may attain the size of a
small hazel-nut.
=The diagnosis= presents no difficulty. Puncture or incision reveals the
fact that the abscesses are filled with white sebaceous material and are
quite free from parasites.
=The prognosis= is not grave. Recovery occurs spontaneously in a few
weeks.
=Treatment.= Liquid emollient applications and the opening of the small
follicular abscesses appear to represent the only means of hastening
recovery.
FAGOPYRISM (BUCKWHEAT POISONING).
Fagopyrism is a disease of toxic origin in sheep, and is due to eating
buckwheat (_Polygonum fagopyrum_).
The disease has also been entitled erysipelatous or gangrenous
dermatitis, according to its form and gravity.
=Causation.= The cause is extremely simple, viz., the consumption of
buckwheat and other food pertaining to a like species, such as
_Polygonum persicaria_. The green plant and the straw give the same
results, but the action of light and air are also necessary for the
production of the disease, a fact which is somewhat difficult to
explain.
According to German writers the disease occurs more frequently in white
sheep and lambs than in those in which the skin is of a very dark
colour.
=Symptoms.= When the sheep are fed in folds, with the green plant in
summer or with the straw in winter, nothing unusual is seen, the herds
being, to all appearance, in perfect health. On their being set at
liberty, however, the first symptoms appear, perhaps in less than an
hour. Some animals become restless, make peculiar movements of the head,
and soon display intense congestion of the parts free of wool, together
with redness and swelling of the ears, eyelids, face, throat, etc. The
condition develops with extreme rapidity, the animals being immediately
afflicted with pruritus over the affected regions. If they are not
removed to the quiet and warmth of the fold the symptoms increase and
papules appear, which may be transformed into vesicles and bullæ. In the
fold, on the other hand, all the symptoms rapidly disappear.
The disease rarely assumes an erysipelatous form, but respiratory and
cerebral symptoms, together with fever and vertigo, are not exceptional.
=Treatment.= The feeding on buckwheat should at once be discontinued,
and the patients should be kept in the fold until the toxic principles
have been eliminated, that is, for a month or more.
Bicarbonate of soda may be added to the drinking water. The local
lesions about the head must be kept clean and dressed with antiseptic
astringent lotions.
CHAPTER II.
PHTHIRIASIS.
The term phthiriasis is applied to infestation of the skin with lice.
=Causation.= These diseases are due to the presence of various parasites
which live by destroying the epidermic scales, or by piercing the
superficial layers of the skin. They are of a greyish-yellow colour, and
belong to the genera _Hæmatopinus_ and _Trichodectes_.
The _Hæmatopinus_ forms have pointed heads, and are equipped for
penetrating the skin by suction. The _Trichodectes_ have a large flat
head constructed for masticating.
[Illustration: $1]
[Illustration: $1]
The ox harbours two forms of _Hæmatopinus_ and one of _Trichodectes_,
the _Hæmatopinus eurysternus_ and _tenuirostrus_, and the _Trichodectes
scalaris_.
The sheep suffers from _Trichodectes sphærocephalus_ and a _Melophagus_,
the goat from the _Hæmatopinus stenops_ and the _Trichodectes climax_,
and the pig from the _Hæmatopinus urius_.
=The symptoms= are, with trifling variations, the same in all domestic
animals, the principal being rubbing and itching. The animals scratch,
bite and attempt to rub against hard objects, even abrading the skin
when this is thin and the irritation is severe.
The parasites may, however, remain localised, and it rarely happens that
they are present in any considerable number in all parts of the body.
[Illustration: $1]
In the ox they are principally found in the depression at the back of
the base of the horns, and in the upper margin of the neck and the back.
In the absence of treatment phthiriasis may become generalised over the
entire surface of the body.
The trichodectes and the melophagus of the sheep choose similar points,
but when the wool is long they may be found nearly all over the body.
In the pig the hæmatopinus is found on the neck, in the region of the
poll, about the armpits, and round the eyes and ears.
These parasites, whose powers of increase are astonishing, keep the
patients in a continual state of irritation, causing them to lose
condition and, in the absence of treatment, to die of exhaustion.
=The diagnosis= is very easy, the parasites being visible to the naked
eye.
=The prognosis= is not grave unless the condition affects a large number
of animals in herds. In young animals the prognosis is much graver, for
the little creatures rapidly become anæmic and die in a state of
exhaustion.
=Treatment.= When the byre, fold, or piggery is infested the first point
is to remove the animals and thoroughly disinfect and cleanse all parts.
[Illustration: $1]
After the manure has been cleared out, the walls, mangers, racks, etc.,
are washed with boiling water, or, better still, potash solution, and
disinfected first with vaporised sulphurous acid, then, if necessary,
with a washing of caustic lime.
The patients are afterwards clipped, washed with soft soap and dressed
with anti-parasitic solutions, such as 1 per cent. tobacco juice, or a
mixture of equal parts of benzine and oil or benzine and petroleum,
etc., which give excellent results.
A 3 per cent. creolin solution is also a very active anti-parasitic and
very easy to use.
All these solutions, however, are more or less poisonous and need to be
used with caution, weak solutions only being used at first, particularly
in the case of animals, such as oxen, which are given to licking
themselves.
[Illustration: $1]
[Illustration: $1]
SCABIES—SCAB—MANGE.
The term scabies is given to a group of diseases affecting man and all
domestic animals. These diseases are produced by two classes of
parasites, viz., sarcoptinæ, which live within the epidermis or on the
surface of the skin, and demodectes (_sing._ demodex), which penetrate
into the sebaceous glands and hair follicles.
Scabies, though known from the earliest times, has long been confounded
with constitutional diseases characterised by cutaneous eruptions. The
symptoms shown were formerly regarded as due to the elimination of
“humours” which the organism was casting off, for which reason scabies
was even treated with internal medicines.
At the present time the cause of the disease is perfectly well
understood, as well as the mode of development of the different
parasites. The rate at which these parasites develop is almost
incredible, a fact which explains the highly contagious character of the
disease.
Each species of animal may present several varieties of scabies, caused
by different parasites, such as sarcoptes, psoroptes, chorioptes,
demodectes, etc.
SCABIES IN SHEEP.
Scabies in sheep usually assumes one of three forms—sarcoptic,
psoroptic, or chorioptic scabies. Follicular, or demodectic, mange
affects the eyelids, and is very rare. It is produced by the _Demodex
folliculorum_ var. _ovis_.
SARCOPTIC SCABIES
This scabies has long been recognised as affecting more especially the
head, muzzle, etc. It was mentioned as long ago as the fourteenth
century by Jehan de Brie, but, until Delafond’s time, no one recognised
that it was caused by an acarus. In 1858 Delafond discovered the
parasite in Piedmont sheep.
[Illustration: $1]
=Causation.= Formerly, writers on the subject and shepherds attributed
this disease to the wounds and excoriations which sheep receive in
passing through brambles, holly, etc., or in rubbing against their
racks. The true cause of the disease is the presence under the skin of
the _Sarcoptes scabiei_ var. _ovis_, which passes from sheep to sheep by
direct contact. The animals attempt to rub against everything about
them, even against their neighbours. These parasites can be transferred
from the goat to the sheep, and _vice versâ_.
Walraff, Roloff, Delafond, Gerlach and Railliet have described cases of
infection in man, but the disease is rarely more than of a temporary
character.
=Symptoms.= This form of scabies affects the head and the parts free
from wool.
At first the parasites invade the upper lip and the tissues about the
nostrils, sometimes, but more rarely, the eyes and ears. They cause the
formation of vesicular papules, accompanied by violent itching. The
animal, in rubbing itself, excoriates these papules, which discharge a
fluid and soon become covered with yellowish-brown crusts.
The disease afterwards invades the face, forehead, jaws, and entire
head. The skin becomes wrinkled and the brownish crusts thicker and more
abundant. These are fissured and bleeding, and they give the face the
appearance of one vast sore.
The parasite rarely attacks the region of the elbow, the belly, or the
inside of the thigh. The disease never advances in parts covered by
wool, although in breeds of sheep with thick wool, such as are found in
Algeria and Tunis, the sarcoptic form of scabies may become generalised
and attack the entire body. The extremities of the limbs, however, are
usually attacked after all the head has become involved.
Throughout the course of the disease the patients scratch and rub
themselves, thus tearing off the crusts and causing bleeding and the
formation of new crusts of a blackish hue. This form of scabies about
the head may become complicated with conjunctivitis, the inflammation
extending from the extremity of the eyelids to the conjunctiva. This
arises from the fact that the membrane is frequently injured by the
animal rubbing the parts. Conjunctivitis may be so intense as to lead to
purulent ophthalmia and the loss of the eye.
[Illustration: $1]
=Diagnosis.= Sarcoptic mange in sheep cannot be mistaken for any other
disease on account of its localisation.
=Prognosis.= The disease is not very dangerous, for it is easy to treat,
though if left to itself it might in time become fatal.
=Treatment.= Preventive treatment consists in isolating diseased
animals, cleansing and disinfecting the folds, and preventing the
introduction of diseased animals into healthy flocks.
=Curative treatment.= When the disease is detected at an early stage
anti-psoroptic remedies may be directly employed.
If, however, it is of old standing, the crusts must first be softened
and removed by the use of fatty substances, such as vaseline or oil,
before any curative treatment can be undertaken.
The crusts can be removed in from twenty-four to forty-eight hours by
vigorous washing with soft soap and the application of anti-parasitic
solutions. The omission to wash the parts causes drugs to lose much of
their efficacy.
Helmerich’s ointment, oil of cade, mixtures of oil, benzine and
petroleum, and 3 per cent. to 4 per cent. of tobacco juice, are the
commonest and most efficacious applications.
A non-poisonous ointment may be made by taking 4 ounces of oil of
turpentine, 6 ounces of flowers of sulphur, and 1 lb. of lard. Mix the
ingredients at a gentle heat, and rub in well with the hands or with a
brush, at the same time breaking the crusts. The simple sulphur ointment
may be made of one part of sulphur and four parts of lard; one fourth
part of mercurial ointment may be added. Few remedies are so useful as
sulphur iodide, and it may well be given a trial on head scab.
In most countries this disease has been made the subject of special
legislation.
PSOROPTIC MANGE—SHEEP SCAB.
This is probably the gravest form of mange. It was described by Cato the
Censor in 160 B.C., by Virgil, Juvenal, Celsius, Columella, Pliny,
Vegetius, etc. In 1787 Abildgaard first showed that psoroptic mange in
sheep could be cured by simple external remedies, without internal
medications. In 1809 Walz described the causes, nature, seat, and
treatment of the disease.
Since then, the parasitic, contagious nature of mange or scabies has
been more and more clearly recognised.
=Causation.= Experience and observation have long shown that the only
cause is the presence of the _Psoroptes communis_ (_ovis_). This disease
is much more contagious than that just described. Psoroptic mange or
scabies exclusively affects those portions of the body covered by the
wool, and may for a long time remain unrecognised.
The parasite is visible to the naked eye, though most inspectors employ
the microscope. The adult female is about ¹⁄₄₀ of an inch long and ¹⁄₆₀
of an inch broad; the male is ¹⁄₅₀ of an inch long and ¹⁄₈₀ of an inch
broad. The mites are discovered more easily on a dark background, and if
a portion of the wool and crusts is placed on black paper and exposed to
the sun for a few minutes the parasites will generally be seen crawling
about on the paper.
The disease is transmitted directly or indirectly by contact from
diseased to healthy animals in the folds, fields, or sheep runs. One
diseased sheep may contaminate an entire flock. The disease is extremely
contagious, and may appear even within a week after exposure.
The parasites have exceptional vitality. It is generally stated that,
kept at a moderate temperature on portions of scab, the adults may live
from four to twenty days, but they will occasionally live much longer;
cases are on record where they have lived three, four, or even six weeks
when separated from sheep; if the atmosphere is dry they will generally
die in about fifteen days; but death is often only apparent, for the
mites may sometimes be revived by warmth and moisture even after six or
eight weeks; the fecundated females are especially tenacious of life.
[Illustration: $1]
Experience has shown that in some cases apparently healthy sheep have
become infected in places where no sheep have been kept for four, eight,
twelve, or even twenty-four months. The conditions underlying this
infection are not thoroughly understood. Possibly some of the eggs have
retained their vitality a long time and then hatched out; possibly the
vitality of the fecundated female has also played a _rôle_; while it is
not at all improbable that an entirely new infection has accidentally
been introduced by birds or other animals. Certain authors of high
standing scout the idea that birds can introduce an infection of scab,
but there is no reason why birds should not do this, and there are some
reasons for believing that they do. It has been noticed on the
Experiment Station of the United States Bureau of Agriculture, for
instance, that crows delight in perching on the backs of scabby sheep
and picking at the scab; while so doing it is only natural that small
tags of wool would adhere to their feet, and thus scatter scab.
Delafond’s experiments show that psoroptic mange is most troublesome
amongst thin, ill-nourished, weakly animals, whilst robust sheep in good
condition may be cured simply by attention to cleanliness and abundant
feeding.
In America this disease causes extremely heavy pecuniary loss, second
only in importance to that produced by hog cholera. It has also
interfered very seriously with the export of American sheep.
=The course= of the disease is affected by the time of year and
surrounding conditions. In autumn and winter, when sheep are in
continual contact in a moist, warm atmosphere within the folds, the
disease makes rapid progress. Young, weak, closely-inbred animals, and
those with long, coarse wool, most quickly succumb. Unhealthy
surroundings, damp, and bad ventilation favour the disease. Pure or
mixed bred merino sheep suffer severely. In summer the animals are
generally shorn and live in the open, and the disease then usually
diminishes or may even be arrested.
A study of the life history of the scab parasite is necessary in order
to determine several important points of practical value, such as the
proper time for the second dipping, etc.
The female mite lays about fifteen to twenty-four eggs on the skin, or
fastened to the wool near the skin; a six-legged larva is hatched; these
larvæ cast their skin and become mature; the mites pair and the females
lay their eggs, after which they die. The exact number of days required
for each stage varies somewhat, according to the writings of different
authors, a fact which is probably to be explained by individual
variation, and by the conditions under which the observations and
experiments were made. Thus Gerlach, in his well-known work (1857)
estimates about fourteen to fifteen days as the period required for a
generation of mites from the time of pairing to the maturity of the next
generation. He divides this time as follows: Under ordinary conditions
the eggs hatch in three to four days, although two authors allow ten to
eleven days for the egg stage; three or four days after birth the
six-legged larvæ moult and the fourth pair of legs appears; this fourth
pair is always present when the mites are two-thirds the size of the
adults; when seven to eight days old the mites are mature and ready to
pair; several (three or four) days are allowed for pairing; another
generation of eggs may be laid fourteen to fifteen days after the laying
of the first generation of eggs. Without going into all of the other
observations on these points, it may be remarked that the eggs may not
hatch for six or seven days; the six-legged larvæ may moult when three
to four days old, and become mature; after pairing, a second moult takes
place, lasting four to five days; a third moult follows immediately,
then eggs are laid and the adults die; in some cases there is a fourth
moult, but apparently without any further production of eggs. Accepting
Gerlach’s estimate of fifteen days as an average for each generation of
ten females and five males, in three months time the sixth generation
would appear and consist of about 1,000,000 females and 500,000 males.
[Illustration: $1]
Several practical lessons are to be drawn from these figures: Firstly,
it is seen that the parasites increase very rapidly, so that if scab is
discovered in a flock, the diseased sheep should immediately be
isolated; secondly, if new sheep are placed in a flock, they should
either first be dipped, as a precautionary measure, or they should at
least be kept separate for several weeks to see whether scab develops;
thirdly, since the chances for infection are very great, the entire
flock should be treated, even in case scab is found only in one or two
animals; fourthly, as dipping is not certain to kill the eggs, the sheep
should be dipped a second time, the time being selected between the
moment of the hatching of eggs and the moment the next generation of
eggs is laid. As eggs may hatch between three and seven, possibly ten or
eleven days, and as fourteen to fifteen days are required for the entire
cycle, the second dipping should take place after the seventh day, but
before the fourteenth day; allowing for individual variation and
variation of conditions, the tenth, eleventh, or twelfth day will be the
best time to repeat the dipping.
=Symptoms.= Psoroptic mange attacks the parts covered with wool, so that
attention is only drawn to the disease by some slight injury to the
fleece, which becomes rough, matted, brittle, and liable to fall.
Scabies commences with intense pruritus. The animals scratch and bite
themselves, and tear away the fleece. These symptoms become aggravated
when the animals are hot, as, for instance, when travelling. If the
sheep have travelled through mud, the fleece becomes matted on the neck,
behind the shoulders, and at all points where they are able to scratch
themselves with the hind limbs.
When a scabby sheep is touched at a diseased point, the animal shows
pleasure by nibbling and moving the head up and down.
At an early stage, if the fleece is divided and the skin examined,
little papules may be discovered somewhat less in size than a lentil.
They are of a yellowish colour, and are distinctly visible against the
reddish colour of the skin. These papules are due to the attacks of the
psoroptes.
[Illustration: $1]
They soon become more numerous and even confluent, break and discharge,
become converted into pustules, and cause the formation of crusts. In a
few days the diseased points are covered with a squamous, yellowish,
sticky covering, under which the psoroptes lie hidden and which affords
them nourishment.
The crusts steadily grow thicker and lift the individual fibres of wool,
tearing them from their follicles, so that patches of skin become bare.
The patches thus formed increase in diameter, for the acari leave the
centre, where crust-formation is replaced by abundant desquamation of
the epidermis. The skin is thickened, assumes the character of
parchment, and in old-standing cases becomes wrinkled.
The disease always commences along the back, withers, loins, and the
upper part of the quarters. Thence it spreads to the flanks and sides of
the chest. The psoroptes are almost exclusively confined to recently
affected points on the edges of the scabby patches. They are visible to
the naked eye, and appear as little whitish-brown points.
Scab is specially liable to attack a flock containing lambs and yearling
sheep, whose skin is thin, fine and supple, and therefore more
susceptible to their attacks. If a portion of a scabby flock be shorn,
the shorn animals will probably recover on account of the psoroptes
transferring themselves to the animals with long fleeces.
=The diagnosis= is easy. Psoroptic mange cannot be mistaken for
sarcoptic mange, on account of the different points affected.
Psoroptic mange only attacks regions covered by wool, and sarcoptic
mange those free of wool. A microscopical examination of acari removed
from the diseased animals will, however, immediately remove all doubt.
Nor can the disease be confounded with phthiriasis, the trichodectes
being immediately distinguished from the psoroptes by their greater size
and the shape of their head. Moreover, they are usually to be found on
the front portions of the shoulders.
It is more likely to be mistaken for another disease, termed by some
writers seborrhœa and studied and described by Delafond under the name
of sebaceous folliculitis. This disease appears mostly in autumn, and
attacks animals much exposed to the weather and on moist, cold soils. It
begins with very violent pruritus, followed by biting and loss of
portions of the fleece. The skin is red, inflamed and painful, and the
wounds are covered with large quantities of yellowish acid discharge of
a sticky and offensive nature. The treatment of this disease consists in
placing the sheep in clean, dry, well-ventilated sheds. Recovery is
assisted by clipping and the application of some emollient dressing to
the diseased parts.
The ease with which the disease can be cured and the absence of
parasites enable one to readily distinguish it from psoroptic mange
(scab).
=Prognosis.= The disease is not specially grave, so long as only a few
animals are affected, for it is not difficult to cure by isolation, good
feeding, and proper external treatment; but if scab appears in a flock,
the freedom with which the animals intermingle is such that all are
rapidly attacked, and the irritation produced at once checks their
growth and causes loss in condition. Many ewes give birth to small,
feeble lambs, which are almost certain to die, and in any case the wool
is considerably diminished in value.
Delafond estimated that psoroptic mange formerly attacked one
thirty-fifth of all the sheep in France every year, causing damage to
the extent of five francs per head. At the present time, and since
proper sanitary laws have been instituted, it has become much less
common.
During the bad season of the year the mortality is greater, and may
reach as much as from 40 to 50 per cent. In cases where scab is
accompanied by some other disease, such as distomatosis, it may even
rise to 80 per cent.
The treatment is preventive and curative. =Preventive treatment=
consists in separating the healthy from the diseased animals and in
disinfecting the folds, sheds, etc.
=Curative treatment.= The first point in this treatment consists in
improving the diseased animal’s food both as to quality and quantity.
It is to be observed that the parasite has more difficulty in living on
robust and well-nourished animals. Moreover, observation shows that
transference from poor land to rich pastures is sometimes in itself
sufficient to bring about a spontaneous cure. Such, at least, is the
belief of the Spanish sheep farmers in Estramadura and of the French
shepherds.
The shepherd can do a great deal to arrest the course of the disease. If
he is careful, zealous, intelligent and observant he will quickly note
the first indications of the disease and, by isolating the animals,
check its spread.
The second point consists in shearing the diseased animals, and this
must be carried out at any season of the year. The money loss is
sometimes important, but must be met, for otherwise treatment is
impossible. In cases of localised scab, empyreumatic oil, oil of cade,
solutions of sulphuret of potassium, decoctions of black hellebore
(water 1 quart, fresh rhizome 4 ounces or dry rhizome 2 ounces),
decoction of tobacco and diluted tobacco juice (6 ounces in 1 quart of
water) have been recommended. Such local treatment, however, is often
useless, because incomplete.
When scab is generalised and it is impossible to define the parts
attacked, general treatment is indispensable and the diseased sheep
should be dipped.
As a preliminary, however, and in order to make sure that the
application will produce its effect, the animals after shearing should
be passed, twenty-four hours before the medicinal bath, through a warm
bath containing soap in order to soften and remove the scabs.
Applications of oil or some fatty substance will also soften the scabs,
which may afterwards be removed with a scraper without producing
bleeding. One pound of soft soap may be dissolved in fifty quarts of
water and each sheep plunged into this and scrubbed with a brush for a
few minutes. Washing alone removes a large number of the parasites.
Whatever bath be used it should not be given until four or five hours
after the last feeding. The dips most popular in France are as follows:—
_Tessier’s Bath_ (1810).
For 100 sheep Arsenious acid 1½ parts or lbs.
„ Sulphate of iron 10 „
„ Water 100 „
The above materials should be boiled for ten minutes, and, as a
consequence of the chemical fusion which occurs in the process, the
proportion of arsenious acid dissolved amounts to about 2 drachms per
quart instead of 3¾ drachms.
In this bath the arsenious acid acts as a parasiticide and the sulphate
of iron as an astringent, the latter checking the absorption of toxic
principles by the skin and sores, and preventing the sheep from licking
themselves.
Absorption by the skin is not so dangerous as has been believed.
Rossignol has shown that poisoning need not be feared in chemical baths
unless the proportion of dissolved arsenic is above 150 grains per
quart, especially if the period of immersion does not exceed five
minutes. Even pure solutions of arsenic, free from any astringent, may
be used, provided the quantity in the bath does not exceed 120 grains
per quart.
The bath should, if possible, be kept warm—85° to 95° Fahr. (30° to 35°
C.).
Four men are generally employed for the operation. One drives in the
sheep, two others hold and brush them in the bath, and the fourth holds
the head of the animal above the liquid. Tessier recommended gloves for
the use of the operators, but experience has shown that such a
precaution is unnecessary. The udder, and particularly the teats, of
ewes with young may, if necessary, be smeared with some fatty substance,
such as vaseline or oil, in order to guard against the astringent action
of the liquid.
Each sheep is plunged in the bath for one or two minutes, or five
minutes at the most. All the diseased spots must be brushed, rubbed and
cleansed; but care must be taken not to make them bleed.
Tessier suggested leaving the animals for twenty-four hours in some
disinfected place, without straw or food, to prevent these materials
from being wetted by the liquid which runs from the fleece, and which,
if afterwards eaten, might have a poisonous effect. Here, again, the
danger has been exaggerated. Delafond has shown that sheep may be given
a fluid ounce of Tessier’s bath for eight days running without producing
the slightest unfavourable symptom.
Tessier’s bath is excellent from the therapeutic standpoint, but it
imparts a yellow tint to the fleece, which is thus rendered less
valuable. The mixture has therefore been modified in various ways.
_Clément’s Bath_ (1846).
For 100 sheep Arsenious acid 1·5 parts or lbs.
„ Sulphate of zinc 5 „
„ Water 100 „
In this bath every quart contains about 2½ drachms of arsenious acid.
Its toxic power, therefore, is considerably greater than that of
Tessier’s bath.
Clément’s formula has one drawback. The sulphate of zinc may be mistaken
for a non-astringent alkaline sulphate (sulphate of soda), and as a
consequence poisoning may occur, as experience has shown.
Mathieu of Sèvres replaced the sulphate of iron by an equal quantity of
alum. In this case, each quart of the bath contains 2½ drachms of
arsenious acid.
Clément’s and Mathieu’s formulæ have given just as good results as
Tessier’s.
A last formula is that of Professor Trasbot. The aloes is of very little
use, however, because it is almost insoluble.
For 100 sheep Arsenious acid 2 lbs.
„ Sulphate of zinc 10 „
„ Aloes 1 „
„ Water 25 gallons.
_Condition of the animals after the bath._—On leaving the bath the
abraded parts are slightly cauterised. During the five or six following
days the skin is stiff, and covered with adherent crusts over the points
attacked by the parasites. The animals no longer scratch or bite
themselves.
Towards the eighth day the crusts fall, the skin appears supple and of a
pink colour, and the wounds cicatrise. In animals which have suffered
for a long time recovery is much slower, and may extend over from thirty
to fifty days. The wool again grows soft and bright, while the sheep
rapidly regain their spirits and condition. The cicatrisation of the
wounds is often accompanied by intense itching, which must not be taken
as a sign of the persistence of the disease. It is well, however, to
keep the animals under observation at this period.
Under any circumstances, six weeks or two months should always be
allowed to elapse before giving a second bath. Should a few spots appear
to be attacked secondarily, they may be moistened with a little of one
of the bath liquids.
In Germany the creolin bath is generally employed:
For 100 sheep { Water 250 gallons or parts.
„ { Creolin 6·5 „
Each sheep is bathed a second time after an interval of one week, the
animal being immersed for three minutes in the bath and thoroughly
scrubbed with a brush. The efficacy of this method, however, is less
certain.
In America, where the flocks are large and scabies is frequent, sulphur
baths are employed, the baths themselves being of great size. The
animals are forced to pass through them and remain there for some
minutes.
The size and value of American, Australian, and New Zealand flocks
demand that the modes of treatment practised and the experience gained
in these countries should receive something more than passing notice. We
therefore purpose giving a short _résumé_ of some parts of the very
valuable monograph on sheep scab issued in 1897 by Dr. Salmon and Mr.
Stiles, for the American Bureau of Animal Industry.
In selecting a dip the question of expense will naturally arise; next,
the question as to whether or not scab actually exists in the flock to
be dipped. The facilities at hand, the set-back to the sheep, and the
length of the wool are also matters for consideration, as well as the
pastures into which the dipped sheep are to be placed.
_Expense._—In estimating the expense one should consider not only the
actual outlay for the ingredients of the ooze, but the cost of fuel and
labour, the injury, if any, to the sheep, and the liability of not
curing the disease. It is much more economical to use an expensive dip
and cure scab, than it is to use a cheap dip and fail to cure it.
_Does scab exist in the flock?_—If scab does not actually exist and the
wool is long, the dipping in this case simply being a matter of
precaution, it is best not to select a dip containing lime.
_The facilities at hand for preparing dip._—If fuel is very scarce, so
that it is impracticable to boil the mixture for at least two hours, the
lime-and-sulphur dips should not be selected.
[Illustration: $1]
_The pastures._—In case it is necessary to place the dipped sheep on the
same pastures they occupied before being dipped, it is always best to
use a dip containing sulphur. If a proprietary dip is selected under
those circumstances, it is suggested that sulphur be added, about 1 lb.
of flowers of sulphur to every 6 gallons of dip. The object in using
sulphur is to place in the wool a material which will not evaporate
quickly, but will remain there for a longer period of time than the scab
parasites ordinarily remain alive away from their hosts. By doing this
the sheep are protected against reinfection.
Sulphur is one of the oldest known remedies for scab; its use is best
known in the tobacco-and-sulphur dip and in the lime-and-sulphur dip.
These home-made mixtures are the two dips which have played the most
important _rôles_ in the eradication of scab from certain English
colonies, and their use is extensive in America.
_The Tobacco-and-Sulphur Dip._
[Illustration: $1]
The formula as given here, and as adopted by the New South Wales
sanitary authorities, appears to have first been proposed in 1854 by Mr.
John Rutherford. “On the Hopkins Hill Station Mr. Rutherford, with two
dressings of these ingredients, then cured over 52,000 sheep which had
been infected for eighteen months. Since then millions of scabby sheep
have been permanently cured in Victoria in the same way, and in South
Australia and New South Wales hundreds of thousands of scabby sheep have
also been cleansed with tobacco and sulphur. Judging, therefore, from
the experience of the three colonies, there is no medicament or specific
yet known that can be compared with tobacco and sulphur as a thorough
and lasting cure for scab in sheep.” (Dr. Bruce, Chief Inspector of
Sheep for New South Wales.)
The proportions adopted by Rutherford, and afterwards made official by
the scab sanitary authorities, are—
Tobacco leaves 1 lb.
Flowers of sulphur 1 „
Water 5 gallons.
The advantage of this dip lies in the fact that two of the best scab
remedies, namely, tobacco (nicotine) and sulphur, are used together,
each of which kills the parasites, while the sulphur remains in the wool
and protects for some time against reinfection. As no caustic is used to
soften the scab, heat must be relied on to penetrate the crusts.
_Directions for preparing the dip._—Infusing the tobacco:—Place 1 lb. of
gold-leaf or manufactured tobacco for every 6 gallons of dip desired in
a covered boiler of cold or lukewarm water, and allow to stand for about
twenty-four hours; on the evening before dipping bring the water to near
the boiling point (212° Fahr.) for an instant, then remove the fire and
allow the infusion to stand overnight.
Thoroughly mix the sulphur (1 lb. to every 6 gallons of dip desired)
with the hand in a bucket of water to the consistency of gruel.
When ready to dip, thoroughly strain the tobacco infusion from the
leaves by pressure, mix the liquid with the sulphur gruel, add enough
water to make the required amount of dip, and thoroughly stir the entire
mixture.
_Lime-and-Sulphur Dips._
Under the term “lime-and-sulphur dips” is included a large number, of
different formulæ requiring lime and sulphur in different proportions.
To give an idea of the variety of the lime-and-sulphur dips, the
following list is quoted, the ingredients being reduced in all cases to
avoirdupois pounds and United States gallons:
(1.) The original “Victorian lime-and-sulphur dip,” proposed by Dr.
Rowe, adopted as official in Australia:
Flowers of sulphur 20⅚ lbs.
Fresh slaked lime 10⁵⁄₁₂ „
Water 100 gallons.
(2.) South African (Cape Town) official lime-and-sulphur dip, February
4th, 1897:
Flowers of sulphur 20⅚ lbs.
Unslaked lime 16⅔ „
Water 100 gallons.
(3.) Fort Collins lime-and-sulphur dip:
Flowers of sulphur 33 lbs.
Unslaked lime 11 „
Water 100 gallons.
(4.) A mixture which, used to some extent by the Bureau of Animal
Industry, contains the same proportions of lime and sulphur (namely, 1
to 3) as the Fort Collins dip, but the quantities are reduced to—
Flowers of sulphur 24 lbs.
Unslaked lime 8 „
Water 100 gallons.
In case of fresh scab Formula No. 4 will act as efficaciously as the
dips with a greater amount of lime, but in cases of very hard scab a
stronger dip, as the Fort Collins dip, should be preferred; or, in
unusually severe cases, an ooze with more lime in proportion to the
amount of sulphur, such as the Victorian (No. 1) or the South African
(No. 2) dip might be used.
_Prejudice against Lime-and-Sulphur Dips._
There is at present great prejudice (a certain amount of it justified,
no doubt) against the use of lime and sulphur, emanating chiefly from
the agents of patent or proprietary dips and from the wool
manufacturers.
In the first place, it is frequently asserted that lime and sulphur does
not cure scab. Experience in Australia and South Africa, as well as in
America, has shown beyond any doubt that a lime-and-sulphur dip, when
properly proportioned, properly prepared, and properly used, is one of
the best scab eradicators known.
It is claimed by some that it produces “blood poisoning.” But the cases
of death following the use of lime-and-sulphur dips have been
infinitesimally few when compared with the number of sheep dipped in
these solutions, and when compared with the deaths which have been known
to follow the use of certain proprietary dips. The details of such
accidents, so far as they have been reported, have not shown that death
was due to any property prepared and properly used lime-and-sulphur dip.
It is highly probable that the cases of so-called “blood poisoning” of
shear-cut sheep are generally due to an infection with bacteria in stale
dip containing putrefying material.
The greatest objection raised against the use of lime-and-sulphur dip is
that it injures the wool. This objection is raised by many wool
manufacturers and echoed with ever-increasing emphasis by the
manufacturers of prepared dips; while, after years of extensive
experience with properly prepared dip, its injury to the wool is
strongly and steadfastly denied by the Agricultural Department of Cape
Colony.
It is believed that a certain amount of justice is attached to this
objection to lime and sulphur as generally used; unless, therefore, lime
and sulphur can be used in a way which will not injure the wool to an
appreciable extent, we should advise against its use in certain cases;
in certain other cases the good accomplished far outweighs the injury it
does. Let us, therefore, examine into this damage and its causes.
[Illustration: $1]
The usual time for dipping sheep is shortly after shearing, when the
wool is very short; whatever the damage at this time, then, it can be
only slight, and the small amount of lime left in the wool will surely
do but little harm.
In full fleece lime and sulphur will cause more injury. In Australia the
deterioration was computed by wool buyers at 17 per cent., although in
Cape Colony the Department of Agriculture maintains that if properly
prepared, and if only the clear liquid is used, the sediment being
thrown away, the official lime-and-sulphur formula will not injure the
long wool. The United States Bureau of Agriculture have found some
samples of wool injured by dipping, while on other samples no
appreciable effect was noticeable.
If a lime-and-sulphur dip is used, care must be taken to give the
solution ample time to settle; then only the clear liquid should be
used, while the sediment should be discarded. In some of the above tests
on samples of wool it was found that the dip with sediment had produced
very serious effects, even when no appreciable effects were noticed on
samples dipped in the corresponding clear liquid.
Experience has amply demonstrated that a properly made and properly used
lime-and-sulphur dip is one of the cheapest and most efficient scab
eradicators known, but its use should be confined to flocks in which
scab is known to exist, and to shorn sheep, with the exception of very
severe cases of scab in unshorn sheep. It should only be used when it
can be properly boiled and settled. The use of lime-and-sulphur dips in
flocks not known to have scab, especially if the sheep are full fleeced,
cannot be recommended; in such cases tobacco, or sulphur and tobacco, is
safer and equally good.
All things considered, where it is a choice between sacrificing the
weight of sheep and to some extent the colour of the wool by using
tobacco and sulphur, and sacrificing the staple of the wool by using
lime and sulphur, the owner should not hesitate an instant in selecting
tobacco in preference to lime. The loss in weight by using tobacco and
sulphur is not much greater than the loss in using lime and sulphur,
while the loss in staple is of more importance than a slight
discoloration.
_Preparation of the mixture._—Take 8 to 11 lbs. of unslaked lime, place
it in a mortar-box or a kettle or pail of some kind, and add enough
water to slake the lime and form a “lime paste” or “lime putty.”[8]
Footnote 8:
Many persons prefer to slake the lime to a powder, which is to be
sifted and mixed with sifted sulphur. One pint of water will slake 3
lbs. of lime if the slaking is performed slowly and carefully. As a
rule, however, it is necessary to use more water. This method takes
more time and requires more work than the one given above, and does
not give any better results. If the boiled solution is allowed to
settle the ooze will be equally safe.
Sift into this lime paste three times as many pounds of flowers of
sulphur as of lime, and stir the mixture well.
Be sure to weigh both the lime and the sulphur. Do not trust to
measuring them in a bucket or to guessing at the weight.
Place the sulphur-lime paste in a kettle or boiler with about
twenty-five to thirty gallons of boiling water, and boil the mixture for
two hours at least, stirring the liquid and sediment. The boiling should
be continued until the sulphur disappears, or almost disappears, from
the surface; the solution is then of a chocolate or liver colour. The
longer the solution boils the more the sulphur is dissolved and the less
caustic the ooze becomes.
Pour the mixture and sediment into a tub or barrel placed near the
dipping vat and provided with a bung-hole about 4 inches from the
bottom, and allow ample time (two to three hours, or more if necessary)
to settle.
When fully settled draw off the clear liquid into the dipping vat, and
add enough water to make a hundred gallons. _Under no circumstances
should the sediment be used for dipping purposes._
[Illustration: $1]
To summarise the position of the United States Department of Agriculture
on the lime-and-sulphur dips:—When properly made and properly used these
dips are second to none and equalled by few as scab eradicators. There
is always some injury to the wool resulting from the use of these dips,
but when properly made and properly used upon shorn sheep, it is
believed that this injury is so slight that it need not be considered;
on long wool the injury is greater and seems to vary with different
wools, being greater on a fine than on a coarse wool. This injury
consists chiefly in a change in the microscopic structure of the fibre,
caused by the caustic action of the ooze. When improperly made and
improperly used the lime and sulphur dips are both injurious and
dangerous, and in these cases the cheapness of the ingredients does not
justify their use. In case scab exists in a flock and the farmer wishes
to eradicate it, he cannot choose a dip which will bring about a more
thorough cure than will lime and sulphur (properly made and properly
used), although it will be perfectly possible for the farmer to find
several other dips which will, when properly used, be nearly or equally
as effectual as any lime-and-sulphur dip. There is no dip to which
objections cannot be raised.
_Arsenical Dips._
There are both home-made arsenical dips and secret proprietary arsenical
dips. It is well to use special precautions with both, because of the
danger connected with them. One of the prominent manufacturers of dips,
a firm which places on the market both a powder arsenical dip and a
liquid non-poisonous dip, recently summarised the evils of arsenical
dips in the following remarkable manner:
“The drawbacks to the use of arsenic may be summed up somewhat as
follows: (_a_) Its danger as a deadly poison. (_b_) Its drying effect on
the wool. (_c_) Its weakening of the fibre of the wool in one particular
part near the skin, where it comes in contact with the tender wool roots
at the time of dipping. (_d_) Its not feeding the wool or stimulating
the growth, or increasing the weight of the fleece, as good oleaginous
dips do. (_e_) The danger arising from the sheep pasturing, after coming
out of the bath, where the wash may possibly have dripped from the
fleece, or where showers of rain, after the dipping, have washed the dip
out of the fleece upon the pasture. (_f_) Its occasionally throwing
sheep off their feed for a few days after dipping, and so prejudicing
the condition of the sheep. (_g_) Its frequent effect upon the skin of
the sheep, causing excoriation, blistering, and hardness, which stiffen
and injure the animal, sometimes resulting in death.”
Although this manufacturer has gone further in his attack upon arsenic
than the United States Bureau of Agriculture would have been inclined to
do, it must be remarked that when a manufacturer of such a dip cannot
speak more highly of the chief ingredient of his compound than this one
has done in the above quotations, his remarks tend to discredit dips
based upon that ingredient. Bruce, the Chief Inspector of Live Stock for
New South Wales, speaking of arsenical dips, says: “Arsenic and arsenic
and tobacco (with fresh runs) cured 9,284 and failed with 9,271.”
It may be said, on the other hand, that arsenic really has excellent
scab-curing qualities; it enters into the composition of a number of the
secret dipping powders, and forms the chief ingredient in one of the
oldest secret dips used. This particular dip has been given second place
(with some qualifications) among the officially recognised dips in South
Africa.
_Formulæ for arsenical dips._—Finlay Dun recommends the following:—Take
3 lbs. each of arsenic, soda ash (impure sodium carbonate) or pearl ash
(impure potassium carbonate), soft soap, and sulphur. A pint or two of
naphtha may be added if desired. The ingredients are best dissolved in
10 to 20 gallons of boiling water, and cold water is added to make up
100 gallons. The head of the sheep must, of course, be kept out of the
bath.
A mixture highly endorsed by certain parties consists of the following
ingredients:
Commercially pure arsenite of soda 14 lbs.
Ground roll sulphur 34½ „
Water 432 gallons (U.S.)
The arsenite of soda is thoroughly mixed with the sulphur before being
added to the water.
_Precautions in use of arsenical mixtures._—Any person using an
arsenical dip should bear in mind that he is dealing with a deadly
poison. The following precautions should be observed:
(1) Yards into which newly-dipped sheep are to be turned should first be
cleared of all green food, hay, and even fresh litter; if perfectly
empty they are still safer. (2) When the dipping is finished, the yard
should be cleaned, washed, and swept, and any unused ooze should at once
be poured down a drain which will not contaminate food or premises used
by any animals. (3) Dipped sheep should remain in an open, exposed
place, as on dry ground. (4) Overcrowding should be avoided, and every
facility given for rapid drying, which is greatly facilitated by
selecting fine, clear, dry weather for dipping. (5) On no account should
sheep be returned to their grazings until they are dry and all risk of
dripping is passed.
The feeling of the United States Bureau of Agriculture towards arsenical
dips is shown by the following:
_Suggestion as to danger._—The formulæ given above are copied from the
writings of men who have had wide experience in dipping, but this Bureau
assumes no responsibility for the efficacy of the dips given, or for
their correct proportions. Furthermore, as long as efficacious
non-poisonous dips are to be had, we see no necessity for running the
risks attendant upon the use of poisonous dips.
_Carbolic Dips._
This class of dips kills the scab mites very quickly, but unfortunately
the wash soon leaves the sheep, which is consequently not protected from
reinfection in the pastures. If, therefore, a carbolic dip is selected,
it is well to add flowers of sulphur (1 lb. to every 6 gallons) as a
protection against reinfection.
The advantages of carbolic dips are that they act more rapidly than the
tobacco or sulphur dips, and that the prepared carbolic dips are very
easily mixed in the bath. They also seem, according to Gillette, to have
a greater effect on the eggs of the parasites than either the sulphur or
the tobacco dips. The great disadvantages of this class of dips
are—first, in some of the proprietary dips, that the farmer is uncertain
regarding the strength of material he is using; second, the sheep
receive a greater set-back than they do with either lime and sulphur or
tobacco.
[Illustration: $1]
The United States Bureau of Agriculture is inclined to be extremely
conservative in regard to them, and to advise their manufacturers to
prepare them in a guaranteed strength with more explicit directions for
use than are to be found in the present circulars.
One of the prominent proprietary carbolic dips was formerly recognised
as one of the three official dips in New South Wales, but it has now
been erased from the list. In Cape Town carbolic dips are not much used,
and in the official reports little is said concerning them.
The United States Bureau of Animal Industry gives the following advice
as regards dipping:
(1.) Select a dip containing sulphur. If a prepared “dip” is used which
does not contain sulphur, it is always safer to add about 16½ lbs. of
sifted flowers of sulphur to every 100 gallons of water, especially if,
after dipping, the sheep have to be returned to the old pastures.
[Illustration: $1]
(2.) Shear all the sheep at one time, and immediately after shearing
confine them to one-half the farm for two to four weeks. Many persons
prefer to dip immediately after shearing.
(3.) At the end of this time dip every sheep (and every goat also, if
there are any on the farm).
(4.) Ten days later dip the entire flock a second time.
(5.) After the second dipping, place the flock on the portion of the
farm from which they have been excluded during the previous four or five
weeks.
(6.) Use the dip at a temperature of 100° to 110° Fahr.
(7.) Keep each sheep in the dip for two minutes by the watch—do not
guess at the time—and duck its head at least once.
(8.) Be careful in dipping rams, as they are more likely to be overcome
in the dip than are the ewes.
(9.) Injury may, however, result to pregnant ewes, which must on this
account be carefully handled. Some farmers arrange a stage, with sides,
to hold the pregnant ewes, which is lowered carefully into the vat, and
raised after the proper time.
(10.) In case a patent or proprietary dip, especially an arsenical dip,
is used, the directions given on the package should be carried out to
the letter.
CHORIOPTIC MANGE, SYMBIOTIC MANGE, FOOT SCAB.
This disease was studied in Germany by Zürn in 1874, and by Schleg in
1877. It has not yet been seen in France.
=Causation.= The sole cause is the presence of _Chorioptes scabiei_ (_v.
ovis_). Contagion is favoured by the animals being in poor condition.
The disease extends very slowly. Only 2 to 3 per cent. of the animals
are affected, and the sufferers are usually those with fine skins.
German shepherds consider this disease to be due to an excessive
allowance of salt, because it is most common during the winter, when the
sheep are housed. Needless to say, this theory is incorrect.
=Symptoms.= Sometimes this form of mange attacks the limbs and develops
very slowly. It commences about the pasterns, and gradually extends
upwards towards the knee or hock. It really advances beyond these
points. The parasites are much smaller than those of common scab, and
are often overlooked. The sheep stamp their feet and scratch and bite
the infected parts, sometimes transferring the disease to the lips and
face, where it may persist for a time.
[Illustration: $1]
In very old standing cases which have been entirely neglected, it may be
met with in the region of the armpit and thigh, the limbs becoming
swollen so as to suggest lymphangitis. In the folds of the hock and
pastern the thickening of the skin may lead to the formation of
yellowish or brownish crusts, according to whether the exudation is
merely of a serous character or accompanied by bleeding.
=The diagnosis= is easy. The parasites are found in the thickness of the
crusts, and are readily recognised under the microscope.
=The prognosis= is not grave, because of the comparative rarity of the
disease and its mildly contagious character. This disease, moreover,
never attacks the head or body, but remains localised in the lower
portions of the limbs.
=Treatment.= The crusts should be removed by washing or by standing the
animals for a time in warm water. Simple cleanliness often suffices,
but, to save time, some anti-parasitic may be used. The condition is
easily cured even without disinfecting the folds.
MANGE IN THE OX.
Bovine animals may be attacked by three varieties of mange, all of which
have long been known.
SARCOPTIC MANGE.
This is not of any great clinical importance, as it is purely
accidental, and only results from the conveyance of sarcoptes from other
animals, such as the horse, sheep, dog, goat or cat, to an animal of the
bovine species. That the disease does occur, however, is shown by the
following excerpt from a report by Professor McFadyean: The animal
showed no symptom of skin disease at the time of purchase, but soon
after it was brought home it was noticed to be rubbing, and the skin
began to assume an unhealthy appearance. When seen in January (four
months after purchase) it was rather poor, although it had been in very
good condition when sold. Almost the entire skin had become affected,
including that of the legs down to the top of the hoofs. There had been
extensive loss of hair, and the skin was thick, grey, wrinkled, and dry.
At some places it had become thrown into thick folds. Only a few scabs
or crusts had formed where the animal had recently rubbed itself. In
some scurf scraped from what seemed to be the parts most recently
invaded, numbers of acari were without much difficulty found with the
microscope.
A good many cases of mange of undetermined character have been reported
as occurring among cattle in various parts of England during the last
year or two, and in a number of instances the disease was believed to
have been contracted during exhibition at a show. It is not improbable
that some or all of these were cases of this sarcoptic mange, and in
view of its very contagious character it is desirable that care should
be taken to exclude from shows animals exhibiting any symptom of the
disease.
PSOROPTIC MANGE.
This condition has also been termed dermatodectic mange. This is very
rare, and, like the former, of trifling clinical importance.
=Causation.= It is due to infection with _Psoroptes communis_ (_v.
bovis_). Poor condition, want of grooming, bad hygienic surroundings and
general neglect, facilitate its spread.
=Symptoms.= It commences at the base of the neck, in rarer cases at the
sides of the neck, along the withers, and at the root of the tail;
thence it gradually attacks the croup, loins, back, shoulders, sides of
the chest, and finally all the body with the exception of the limbs.
It produces violent itching, the animal continually scratching itself,
even causing raw sores. At first the epidermis is elevated in little
miliary points, which may be isolated or confluent, and are filled with
serosity. This fluid discharges, gluing together the hairs; it then
hardens and produces adherent crusts, which increase in number and size.
The skin exhibits large numbers of bare, mangy points; these have
irregular margins, and are covered with thick, grey, scaly crusts. The
psoroptes are found under these crusts.
The skin becomes hard, dry, fissured and cracked, and sometimes forms
large folds on the sides of the neck, shoulders and chest.
The influence of the seasons on the development of this disease has been
well shown by Gerlach and Muller. The disease commences about the end of
autumn, when the animals are stabled. It continues to extend until
February, but diminishes as soon as the animals return to the fields in
spring. The crusts fall, the hair again grows, and the animal appears to
be cured, but the disease again revives during the autumn. The psoroptes
lie hidden during the summer round the poll and the horns. The disease
seldom attacks animals at grass and in good condition, or those over
three years old. Calves, yearlings, and two-year-olds in poor condition
suffer most.
When the disease is very extensive, the animals lose condition and may
even die.
=Diagnosis.= Psoroptic mange in the ox may be mistaken for several
cutaneous diseases, to which it has a certain resemblance, as for
instance phthiriasis and the first stage of ringworm.
These different diseases, however, show their own distinctive symptoms
on a careful examination.
=The prognosis= only becomes grave when the disease has been neglected
and the animals are greatly reduced in condition. When recent, this form
of mange can readily be cured by the application of parasiticides.
=Treatment.= As in dealing with all transmissible diseases, the animals
must be isolated and washed with soap, and the diseased parts must be
dressed with some parasiticide, such as sulphur ointment. The best
preparations are: Benzine and petroleum in equal quantities;
concentrated solution of sulphuret of potassium (8 ounces to the quart);
Helmerich’s ointment; diluted creolin solution; decoctions of tobacco;
ointment of pentasulphuret of potassium, and oil of cevadilla.
One or two applications are generally sufficient to effect a cure, and
relapses are not likely to take place if the stable is disinfected. In
America the disease is common in the West and North-West, where it is
treated by the lime-and-sulphur bath recommended for sheep scab (which
see). Large vats are constructed, and the oxen are lowered into these by
means of a wooden cage controlled by machinery, which is operated either
by a small engine or more frequently by a horse.
The food should be of good quality, for good general health plays a
great part in resisting parasitic invasions.
CHORIOPTIC MANGE.
This disease has also been termed dermatophagic and symbiotic mange.
It was first described in 1835 by Kégélaar, and has been the subject of
investigation by Hering, Gerlach, Delafond, and Mégnin.
=Causation.= It is produced by the _Chorioptes bovis_, and is
transferred with difficulty, even by cohabitation.
=Symptoms.= This form of mange in the ox does not affect the same parts
as in other animals. In the horse, etc., it attacks the limbs, whilst in
the bovine species it is usually found at the base of the tail. It
causes slight itching. The diseased region becomes covered with numerous
little pellicles, the hairs gradually fall, crusts form, and the skin
shows deep cracks. When the disease is completely neglected, it may
extend to the loins, back, sides of the body and shoulders. It may also
affect the perineal region, the inner surface of the thighs, and in fact
the whole of the body if the animals are young and in poor condition.
=Diagnosis.= At the outset it is difficult to distinguish between
chorioptic and psoroptic mange, and the use of the microscope is
necessary. On a superficial examination chorioptic mange may be mistaken
for phthiriasis when the latter attacks the posterior portions of the
body, particularly the base of the tail, and when it is accompanied by
eruptions, loss of hair, and intense itching.
The distinction between the two conditions, however, is extremely easy
after an examination of the two parasites.
=Prognosis.= The disease is of slight gravity, and does not threaten the
animal’s health unless neglected for so long a time that the parasites
invade all parts of the body. In that case the disease may cause anæmia
and loss of condition.
=The treatment= of this form of mange comprises nothing special, it
being sufficient to proceed as directed in the previous article.
The stables ought always to be thoroughly disinfected.
MANGE IN THE GOAT.
The goat suffers from the attacks of sarcoptes, psoroptes, and
chorioptes, but up to the present time only two forms of mange have been
described, sarcoptic and chorioptic mange.
Psoroptes have only been found about the eye, where the disturbance they
produce is comparatively trifling.
SARCOPTIC MANGE.
This disease was noticed in 1818 in goats imported into France from
Thibet.
Henderson published the history of a Persian goat which conveyed
sarcoptic mange to men and horses. In 1851 Walraff noticed an epizootic
mange which attacked the goats in the Prattigau valley of Switzerland,
which was transmitted to men and sheep and which exhibited the clinical
characters of sarcoptic mange.
=Causation.= This disease is due to the presence of _Sarcoptes scabiei_
(_v. capræ_).
It sometimes occurs in an epizootic form, as Walraff’s observations
show, but it seems specially to attack goats in Asia and Africa.
This mange may be transmitted by the goat to sheep, in which animals it
attacks the head and muzzle; it is particularly contagious in sheep
having coarse, dry fleeces.
Similarly sarcoptic mange of sheep may be conveyed to the goat, in which
animal it extends all over the body.
=Symptoms.= This mange causes intense itching. It first attacks the head
and ears, then the trunk, belly, udder, and limbs. If the disease is
neglected it becomes generalised very rapidly, and the animals waste
away and die in a very short time.
At the commencement little crusts, which discharge a viscous liquid, are
found about the head. The goats rub themselves raw, and, as in facial
mange of sheep, there appear dry, scaly, branlike patches. After a time
the diseased area extends, the wool falls, and the skin becomes dry,
thick and wrinkled. The appearance is exactly like that of sarcoptic
mange in sheep, the lower part of the head being seldom invaded. The
animals lose condition, waste and die of exhaustion.
=Diagnosis.= The parasite is readily recognised, and the practitioner,
moreover, is often put on his guard by the epizootic character assumed
by the disease.
=The prognosis= is grave. Walraff declared the mortality in Grisons
(Switzerland) to be as high as 20 per cent.
=The treatment= is identical with that of psoroptic mange in sheep.
After the animals have been sheared and washed with soap, they should be
completely immersed in a bath of the character mentioned in connection
with sheep scab. If only one animal is infected, it may be sufficient to
dress it repeatedly with an ointment containing some parasiticide.
CHORIOPTIC MANGE.
This form of mange was noted by Delafond in 1854 at the Jardin des
Plantes (Paris) in some angora goats, and by Mollereau in 1889. The
disease studied by Delafond had invaded both sides of the neck, the
eyes, withers, back, loins, and base of the tail. It was characterised
by partial loss of hair, the finer hair falling and the coarser
remaining in position.
In Mollereau’s case the disease was located in one of the hind pasterns,
and assumed the form of a thickened band, which produced an œdematous
swelling. The chorioptes were discovered in a thick crust formed by the
drying on the hair of the discharge due to their punctures.
=Diagnosis.= The parasites can easily be found under the crusts, and,
once recognised, distinguish the disease from any other infection.
=Treatment.= Ointments containing some parasiticide and solutions of
sulphuret of potassium generally suffice, the disease having little
tendency to become generalised.
MANGE IN THE PIG.
The pig suffers from one variety only of mange. It was described by
Viborg, Gürlt and Spinola, who found a sarcopt in the mange of wild
boars in 1847. Hertwig and Gerlach made a similar observation some years
later. Delafond in 1857 discovered the sarcopt of mange in the pig.
=Causation.= Sarcoptic mange in the pig is due to the presence of
_Sarcoptes scabiei_ (_v. suis_), although the pig may contract
(temporarily) the sarcoptic mange of goats.
Contagion is favoured by poor condition, over-crowding, dirt and bad
hygienic surroundings.
The primitive races of pigs resist the disease better than the improved
races. This mange can be conveyed to man and to other animals.
=Symptoms.= It usually commences about the head, ears, and eyes, and
extends to the quarters, internal surface of the thighs, etc. In the
early phases it is impossible to discover the little galleries under the
epidermis, but closely placed reddish papules may be seen. The active
proliferation of the epidermis, together with discharge, causes the
formation of dry crusts of a greyish-white, silvery tint, adherent while
still thin, easy to detach at a later stage, and sometimes ⅜ of an inch
in thickness. The skin becomes wrinkled, the bristles are shed or
loosened in their follicles, and are glued together in little bunches
before falling. As these patches extend over the whole surface of the
body, the animal appears to be bespattered with dry guano (Muller).
Under the crusts the skin is rough, excoriated, and, about the thorax
and abdomen, is indurated, and sometimes measures 1 to 1½ inches in
thickness. In other parts, particularly at the base of the ears, the
papillæ are hypertrophied; they become as large as a pea, or even a
bean, and, lifting the crusts which cover them, assume the appearance of
the warts sometimes found on the cheeks of dogs or the teats of cows.
Sarcoptes may be found under these epidermic growths, though in order to
obtain them the skin must be scraped until it almost bleeds.
The dimensions of these parasites render them visible to the naked eye.
They are the largest variety of the sarcoptinæ, the egg-bearing female
being half a millimètre in length. Guzzoni has found in the ears
specimens of smaller size.
Mange in pigs develops slowly. When it affects the whole body, it
prevents fattening and causes loss of condition.
=Diagnosis.= This is the only parasitic disease which affects the entire
surface of the body and presents these peculiar powdery crusts.
=Treatment.= All the styes should first be carefully disinfected.
Treatment is commenced by vigorously scrubbing the animal with a brush
dipped in soap and water, and thus getting rid of the crusts as far as
possible.
The animals are afterwards dressed with decoctions of tobacco, with
Helmerich’s ointment, or the other mixtures above mentioned.
DEMODECIC MANGE.
This mange is produced by parasites of the family Demodecidæ (_Demodex
folliculorum_), which live in the hair follicles and sebaceous glands of
several species of mammals.
DEMODECIC MANGE IN THE OX.
This was described in 1845 by Gros, and in 1878 was found by Faxon in
Illinois in the skins of cows prepared for tanning. It has not been met
with in France. The skins examined by Faxon showed numerous rounded
enlargements, resulting from dilatation of the hair follicles in the
regions of the neck and shoulders.
By pressing on these enlargements a whitish, greasy, sebaceous material
was ejected, very rich in demodectes.
DEMODECIC MANGE IN THE GOAT.
[Illustration: $1]
This was first noticed by Niederhaüsern, at the Bern Veterinary College,
in a goat which showed little nodosities over different parts of the
trunk, varying in size between that of a pea and that of a hazel-nut. By
forcibly compressing these enlargements a yellowish-grey semi-solid
material, containing a considerable number of demodectes, was caused to
exude.
In 1885 Nocard and Railliet found the same parasite in a young he-goat;
the pustules were spread over the sides and flank. =Treatment= consists
in opening the pustules and dressing them a few times with an
anti-parasitic lotion.
DEMODECIC MANGE IN THE PIG.
This was well described for the first time by Csokor. It was afterwards
seen by Neumann and Lindqvist.
The isolated pustules are of the size of a grain of sand, but when
confluent may reach the size of a hazel-nut. They are sometimes dark in
colour, often deep-seated, are surrounded by a zone of inflammation, and
appear in places where the skin is fine (the groin, neck, belly, etc.).
The demodex becomes lodged and multiplies, not in the hair follicles,
but in the sebaceous glands. Csokor regarded this disease as contagious;
in a herd of one hundred he found twenty-two pigs affected with it.
Lindqvist, however, found but one case in a herd of two hundred.
NON-PSOROPTIC FORMS OF ACARIASIS.
These are produced in farm animals by arachnide belonging to the
families of Trombidiidæ and Ixodidæ.
(1.) =The Leptus autumnalis= is considered to be the larva of the
_Trombidium Holoscriceum_, or silky trombidion. It lives in late summer
and autumn, in the grass.
=Symptoms.= The animals show intense itching, and cannot sleep owing to
burning sensations. They continually rub themselves, and thus,
secondarily, produce excoriated papules and patches resembling those of
eczema. When the papules are very numerous, particularly if the animals
are thin-skinned, more or less extensive erythema may be produced.
At the points attacked the skin swells, becomes red, and sometimes even
violet, and exhibits irregular, isolated or confluent swellings, ¼ to ⅜
of an inch in diameter.
The parasite most commonly becomes fixed round the lips, the forehead,
the cheeks, the sides of the neck, and the extremities.
=The diagnosis= is easy, the discovery of the parasite removing all
doubt.
The condition is of slight importance. The parasites do not live for
more than a few days on the animal’s skin, so that they only produce
temporary disturbance.
=Treatment= consists in bathing the parts with some lotion, such as 2 to
3 per cent. creolin or 2 per cent. chloral, or in applying mixtures of
oil and petroleum, etc.
(2.) =Ixodes hexagonus=, =I. ricinus=, and other species of the tick
family (Ixodidæ) attack sheep, goats, and oxen in France.
=Symptoms.= In sheep the ixodidæ usually affix themselves at points
where the skin is tender and unprotected by wool, as for instance the
thighs, armpit, and upper part of the neck. Their bites produce
irritation, followed by an intense burning sensation, and the formation
of a red blush round the point bitten.
In the ox the ticks fasten on the neck, behind and within the ears, and
also wherever the skin is tender. Until the last few years little
importance was attached to their development, but since it has been
proved that _Rhipicephalus annulatus_ is the active factor in
desseminating Texas fever, ticks have attracted much attention.
It seems, moreover, to be proved by the researches of Lignières that a
form of piroplasmosis exists in France, and it seems possible that the
_Ixodes ricinus_ may be a means of propagation.
=The diagnosis= of acariasis produced by ticks is easy, for the
parasites attain large dimensions.
=Prognosis.= It is difficult at present to say what importance should be
attached to this form of acariasis, but its existence and possible
consequences should be noted.
=Treatment.= Some authors have recommended killing the ticks by touching
them with benzine, petroleum, essence of turpentine, etc., but these
methods do not always succeed. Applications of concentrated solution of
chloral are more effective. When the parasites are so large as to render
this possible it is better to remove them by hand, taking care at the
same time to remove the rostrum, which, if left in place, might cause
more or less suppuration. In countries where ticks are numerous and
large numbers of cattle are infested, the parasites are destroyed by
smearing and dipping.
[Illustration: $1]
(The cattle ticks of America are of especial importance in relation to
the disease known as Texas fever. Those who wish to study the entomology
of this subject are referred to the masterly account and fine coloured
illustrations of Salmon and Stiles, “Cattle Ticks of the United States,”
Ann. Rep. U.S.A. Bureau of Agriculture, 1900, p. 380.)
HYPODERMOSIS IN THE OX (WARBLES).
=Causation.= This is a parasitic disease characterised by subcutaneous
swellings due to the presence of larvæ of the _Hypoderma bovis_. The
larva is met with throughout Europe. It attains the perfect stage during
the summer, from the middle of June to the commencement of September.
The female deposits her eggs on animals with fine skins. These eggs are
elliptical, and provided with a kind of tail of a brownish colour. They
soon become converted into larvæ, provided with rows of little spines.
The manner in which the eggs are laid is not exactly understood, nor are
we better informed regarding the hatching of the young larvæ. Until
recently it was believed that the larva perforated the skin as soon as
it quitted the egg, and then penetrated as far as the subcutaneous
connective tissue. Recent observations, however, have upset this view.
It is probable that this larva, like other gastrophili, is swallowed by
animals of the bovine species, and passes through the intestine into the
surrounding tissues by a path which is yet unknown, possibly by the
blood-vessels, whence it makes its way after a longer or shorter
interval into the subcutaneous connective tissue.
[Illustration: $1]
Certain recent observations seem to support the latter view, which is
also corroborated by known facts regarding hypodermic myiosis in man.
The eggs are laid in summer, and the swellings indicating the presence
of the larvæ only appear during the winter. Henrichsen found young larvæ
in the fatty tissue situated between the periosteum and spinal dura
mater, between the period from December to March.
=Symptoms.= Whatever the mode of development of the larvæ, cutaneous
swellings appear between the months of February and March on the back,
lumbar region, quarters, shoulders and ribs, and, less frequently, over
the chest, belly and thighs.
They vary in number. Commonly there are from ten to twenty, and it is
only in rare cases that less than four or five are found. As soon as
they attain the subcutaneous connective tissue they act as foreign
bodies, causing a circumscribed inflammation, and finally suppuration.
In this way the so-called “warbles” are produced.
Each larva is surrounded by a thick wall, forming a cavity, which
communicates with the outer air by a minute aperture.
When the swelling is sufficiently advanced the larva may be extricated
by pressing with the fingers around the base of the warble. A few days
before it leaves its shelter the larva enlarges the little opening by
thrusting its last rings into it. Soon after the larva has escaped the
discharge of pus ceases, and the skin wound heals.
=Diagnosis.= The times at which the swellings appear and the larvæ are
present render the diagnosis easy.
=Prognosis.= This is seldom grave, for the larvæ rarely cause death. In
cases where they are present in very large numbers, however, they may
set up purulent infection.
=Treatment.= No really effective treatment against warbles is known.
Curative treatment consists in squeezing out or killing the larvæ when
in the subcutaneous tissue, but this is practically useless, as the dead
larvæ then set up prolonged suppuration.
CHAPTER III.
RINGWORM.
The old term “ringworm” is still used to indicate a well-marked skin
disease due to parasitic fungi which grow at the expense of the
epidermis. Other names, such as dermatophytis and epidermophytis, have
been suggested, to indicate the mode in which the parasite grows. The
term dermatomycosis suggests a cutaneous vegetable parasite.
The dermatomycoses of the domestic animals are caused by fungi belonging
to six distinct genera:—
_Trichophyton_ (horse, ass, ox, dog, pig); _Eidamella_ (dog);
_Microsporum_ (horse, dog); _Achorion_ (dog); _Lophophyton_ (fowl);
_Oospora_ (dog).
Ringworm is common in animals of the bovine species, but very rare in
other domesticated animals, except, perhaps, the horse. It is caused by
the growth of a parasite, _Trichophyton mentagrophytes_ (Robin), of the
genus Trichophyton, family Gymnoascea, order Ascomycetes.
The ascosporaceous form of reproduction is still unknown, but the mode
of reproduction by conidia is characteristic. In cultures the mycelium
is represented by growing filaments branching off at right angles, and
by separate superficial aerial reproductive filaments of the conidian
form. There is some reason for believing that these fungi may lead a
saprophytic as well as a parasitic existence, _i.e._, that they can
exist and multiply apart from the animal body.
Their vitality is marked. Various experimenters have transmitted the
disease with crusts kept for eighteen months. Thin declares that in two
and a half years the spores had lost all power of germination. They
resisted immersion in water for two days, but were dead after eight
days. Soft soap and 1 per cent. acetic acid kill them in an hour.
=Symptoms.= The disease most frequently attacks young animals and milch
cows—very rarely adults or old animals. This peculiarity is very
difficult to explain.
In calves, ringworm seems specially to attack the head, the
neighbourhood of the lips, the nostrils and submaxillary region, as well
as the throat and neck. It assumes the form of circular patches, over
which the hair stands erect.
Gruby in 1842 discovered the parasite of tinea tonsurans, or herpes, and
thus proved that the cutaneous lesions were not due to any
constitutional condition, as was long thought, although dirt, bad
hygienic conditions, and crowded stables favoured the spread of
ringworm.
[Illustration: $1]
Direct contact between healthy and diseased animals and the transport of
spores, by combs, brushes, etc., favour contagion. The disease may not
only be conveyed from one animal to another of the same species, but
from the ox to man, and, with somewhat greater difficulty, from the ox
to the horse. Cases of transmission from the ox to the sheep, pig, and
dog have also been recorded.
Mégnin in 1890 attempted to prove that all the trichophytons producing
ringworm in animals do not belong to the same species, and gave the name
of _Trichophyton epilans_ to that usually found in the ox, because it
causes absolute loss of the hair by growing in the follicle, whilst he
named the parasite found in the horse _Trichophyton tonsurans_, because
it only grows on the surface of the skin and in the thickness of the
hair, without causing inflammation of the hair follicle and without
invading it.
The epidermis soon undergoes proliferation, and becomes covered with
crusts, which adhere to the hairs, gluing them together, and finally
causing them to be shed, leaving bare patches the size of a shilling or
a florin. The lesion extends in an ever-widening circle, until it
attains, perhaps, the dimensions of a five-shilling piece or more.
The affected hairs break off level with the free surface of the skin,
rendering the patches more apparent. White hairs are less affected, and
some always remain projecting above the crusts, causing the patches,
when on a white skin, to retain a certain amount of covering.
At first the crust is closely adherent to the skin, and, if forcibly
detached, exposes the dermis, which is swollen and bleeding. Gradually
the centre becomes detached, whilst the periphery, representing a more
recent lesion, continues to adhere. The crusts then rest on a thin layer
of pus, and the dermis, whilst still inflamed, is punctuated with
numerous minute apertures, representing the roots of the detached hairs.
The pus lifts the crust; gradually it dries up and forms superposed
layers, which may or may not prove adherent to the parasitic products,
and which form a new crust. The latter is purely inflammatory in
character, and is left after the fall of the first. It no longer
contains any parasites, at least within its deeper layers.
This second crust dries up in its turn, falls away or breaks up, leaving
a smooth spot, over which the hairs again appear, either at once, or at
least after a short period of desquamation.
The disease is accompanied by well-marked pruritus, more marked at the
commencement and towards the end than during the intermediate period,
but, nevertheless, much less acute than in scabies.
Ringworm may undergo spontaneous cure in from six weeks to three months.
It is more obstinate in calves than in adults, and the want of grooming
tends to increase its duration. If it extends over a large part of the
body the disease may seriously affect the animal’s health, and the cases
described by Macorps prove that where pruritus is violent it seriously
affects the animal’s general condition.
The patches may finally become confluent and the disease extend over the
whole of the neck, shoulder and back, or it may attack the entire body,
leaving it practically hairless.
When the hair has been shed, the crusts and discharge seen at the outset
disappear, and the bare spots are covered with a scaly coating, due to
excessive production of epidermic cells.
According to Gerlach, such crusts are thicker where the skin is black,
and often exhibit a greyish-white, fibrous, starchy appearance. On
unpigmented portions of the skin, which are usually thinner, the crust
is less dense, and is slightly yellowish. Gerlach failed to reinoculate
the bare patches of skin left after a primary eruption of ringworm.
Where the hair had again grown an eruption could again be produced,
though it was usually of a feeble character.
In a second form of the disease, the spots may be of very small
dimensions. The hair falls away, but there is no exudative inflammation,
and no formation of crusts. In this second form the animals simply show
characteristic circular bare spots about the head, neck, or shoulders.
=Causation.= The disease is due to the growth of germs on the skin of
animals which are in a receptive condition. The parasite thereafter
develops in the hairs, the hair follicles and the epidermis, causing
lesions which vary according to the species.
At the present time three groups of ringworm are recognised as occurring
on animals, Trichophytic, Microsporous, and Favus.
Clinically the trichophytons are divided into the _T. ectothrix_, which
lives outside the hair, and both outside and inside the hair follicles;
_T. endothrix_, which penetrates the thickness of the hair itself,
rendering it brittle and easily destroyed; and _T. endo-ectothrix_,
which both surrounds and invades the hair.
The study of artificial growths of these fungi will probably afford
valuable information on the above points. In the ox the particular
parasite is invariably the _Trichophyton mentagrophytes_, whatever may
be the characteristics of the clinical lesion.
In France ringworm is particularly common in Auvergne and Normandy,
where hygienic precautions are neglected, but cases may also be found
throughout the country.
After affecting cows throughout the winter, the disease often disappears
in the spring. Throughout the winter cows are kept in dark and often
filthy sheds, where the parasite propagates rapidly, whilst in spring
they are sent to grass, where the conditions are inimical to contagion.
=Diagnosis.= The diagnosis of ringworm seldom presents any difficulty.
The appearance of the lesions (Fig. 266), their particular tendency to
spread and contagious character, facilitate the diagnosis. They entirely
differ from those of eczema or mange, and should any doubt exist, the
slightest microscopic examination is sufficient to dissipate it. In
ringworm in the ox the base of the hairs is covered with enormous
numbers of spore chains, which do not extend into the depths.
To detect the parasites it is best to shave off a thin fragment of skin
from the periphery of the patch, place it on a slide with a drop or two
of 30 per cent. caustic potash solution, and heat it for a few seconds
almost to boiling point. By applying a cover glass with firm pressure
the epidermal cells are spread out and the parasites can be seen,
especially around the roots of the hairs. Sometimes they form little
dirty-yellow masses, consisting almost exclusively of spores.
When ringworm has attacked the entire surface of the body, it is much
more difficult to distinguish from sebaceous eczema, and a microscopic
examination or experimental inoculation may become necessary.
Inoculation with ringworm material always succeeds with calves.
=Prognosis.= Ringworm is not dangerous in itself. In time it may
disappear spontaneously, but when it extends over the whole body it may
be dangerous. Owing to their bare condition the animals easily catch
cold, while the epidermic proliferation is very great, and makes great
demands on the animal’s bodily powers. Under such circumstances it is
better to slaughter early.