Season of attack by fly, hibernation, botfly of sheep, mode of attack,
embryo, defensive acts of sheep, habitat of larva, mature larva, its
exit, chrysalis in soil, its transformation. Symptoms, sneezing,
snuffling, rubbing of nose, lachrymation, unsteadiness, discharge,
respiratory digestive and febrile disturbances, emaciation, septic
action. Lesions, larva, congestions of mucosa, brain. Treatment,
warmth, errhine, parasiticides, mechanical extractors, trephining,
injections. Prevention, newly turned furrow, quicklime, tar. Other
larva in nose.
Sheep are especially subject to the attacks, in summer and autumn and in
warm sunny barns even in winter, of the Œstrus (Cephalemia) Ovis, the
larva of which hibernates in the nasal sinuses or turbinated bones.
The =sheep-bot-fly= is only about four lines in length, of a light
yellowish or slightly brownish gray hue, hairy, with dull black
transverse lines on the upper surface of the thorax, and a lighter color
on the abdomen where the black lines are more broken. The transparent,
colorless wings extend beyond the body: winglets are long and cover the
poisers: abdomen is formed of five rings.
They appear during the whole summer hiding away in walls, stumps and
grass, unless when pairing or pursuing the sheep to deposit their young.
The mode of attack is difficult to follow on account of the small size,
gray color and rapid flight of the fly and fear and shyness of the
sheep. It cannot be doubted, however, that they approach and drop on the
margin of the nostril, the larva previously hatched from the egg. The
old authors describe the deposition of the egg on the margin of the
nostril and its prompt hatching by the animal heat, but the observations
of Brown, Kelly, Cockrill, Riley and Ormerod abundantly prove that the
fly is viviparous. Cockrill obtained no less than 300 live hatched larvæ
from one fly caught while pursuing a sheep.
The sheep seek to avoid the fly by resorting to dry dusty roads where
they lie with the nose close to the ground, or they stand with the nose
close to the soil and between their fore legs. At other times they will
collect in a dense phalanx with their heads directed toward the centre
of the mass and held low so that the fly cannot reach them. The moment
the fly touches the nose they shake the head, stamp with the feet, and
gallop off with the nose close to the ground, looking from side to side
to see if the fly pursues and frequently smelling at the grass as if
apprehensive of other flies hidden there. If such appear they instantly
turn and scamper to other parts of the field or take refuge in a dry
dusty place or gravel bank.
The =young larva= when deposited on the nostril speedily makes its way
up and takes refuge in the cavities of the turbinated bones and the
frontal and maxillary sinuses, where it passes the winter feeding on the
mucus and the purulent discharges determined by its presence. When
mature it leaves the nose and assumes the chrysalis form in the soil.
The =mature larva= is narrow anteriorly, broad behind: its upper surface
is prominent and rounded, lower surface flat, and furnished at the
anterior of each ring after the third, with a series of pointed
tubercles or spines: the cephalic end bears the buccal organs directed
downward, and bearing two great hooks connected with the hard framework
of the pharynx and recurved downward, backward and outward; mouth small;
antennæ thick and short placed above the buccal organs: the inferior
part of the last ring projects beyond the upper portion and is furnished
with two nodules with intervening spines: pentagonal patches of stigmata
on the last ring: very small anterior stigmata between the first and
second rings. The color is white with brown spines, stigmata and
transverse striæ. Length seven lines to one inch.
When dropped from the nostril in the course of summer they pass into
chrysalis in one or two days; and after a residence of six or eight
weeks in the soil emerge as the perfect fly.
=Morbid Symptoms Caused by the Larvæ in the Head.= =Grub in the Head.=
These bear a close relation to the number of larvæ present. If there are
only two or three no trouble may result. If many there is muco-purulent
discharge from the nose, sniffling breathing, frequent sneezing and
snorting expelling mucus and even blood; shaking of the head; rubbing of
the nose on the fore legs or other objects; weeping eyes; and occasional
unsteadiness of the gait.
In the worst cases the respiration becomes sighing, wheezing or even
snoring; the mouth open; head pendent; appetite fails; a dull, apathetic
condition ensues with grinding of the teeth rolling of the eyes, and,
rapidly advancing emaciation.
Fatal cases are not uncommon but most frequently the larvæ reaching
maturity are dropped and health is promptly re-established. Septic
poisoning from decomposition of dead larvæ and debris is a dangerous
complication.
_Lesions._ These consist in the presence of the larvæ in the sinuses,
with violently congested, purple ulcerated mucous membranes and
collections of pus. The mere presence of the grub is not conclusive as
the majority of the sheep harbor two or three from October to June.
_Treatment._ It is advised to place the sheep in a warm building to
encourage the parasites to come out of their recesses and then introduce
some agent to destroy them or to induce their expulsion by sneezing. The
value of the hot building is probably hypothetical unless the larvæ are
approaching maturity. The following agents are used:—moderately strong
solutions of salt, vinegar, carbolic acid, creosote (1 part to 100 parts
of water), or carbonate of ammonia, lime water, snuff, or even such
irritants as quick lime, oil of turpentine or hellebore. These last must
be used with caution as they are liable to induce fatal inflammation of
the air passages though no larva is present.
By passing a feather up the nostril twisting it round and then
withdrawing it some grubs can usually be withdrawn and there is no harm
in first dipping the feather in some of the milder agents mentioned
above. But the larvæ in the sinuses can never be reached in this way.
In dangerous cases it is best to trephine the outer plate of bone
covering the frontal sinuse and wash out freely with tepid water, lime
water, or benzine. The operation may be performed close in front of the
root of the horn if there is one, or to the inner side of the lower part
of the eye if there is not. A semi-circular flap of skin is to be turned
upward and backward sufficiently large to allow the use of a trephine ⅓
inch in diameter, which is to be used as for _Cœnurus Cerebralis_. The
opening being made the sinuse is to be syringed freely for some time
until the parasites come from the nose in the stream of liquid. The
wound heals very promptly. In the absence of a trephine use a gimlet.
_Prevention._ Some turn up a furrow in the pasturage, in which the sheep
may burrow their noses and evade the fly, others lay down quicklime in
covered boxes which has the further advantage of inducing sneezing and
favoring expulsion of the entering parasites. But perhaps the best plan
is to procure a log and bore a number of holes in it with a two inch
augur; place salt in the holes and smear their margins with tar, and
renew it often. The sheep then takes a protective dressing with every
lick of salt.
=Œstrus Purpureus= (Brauer) is a species which infest the nose, etc., of
the Syrian sheep, and =Cephalemia Maculata= (Wedl) one which infests the
nasal chambers of the Egyptian buffalo and camel.
NASAL CATARRH IN DOG AND HORSE FROM LINGUATULA (PENTASTOMA) TAENIOIDES.
RHINARIA TAENIOIDES.
Form. Family. Habitat when mature, and immature. Development.
Symptoms, sneezing, discharge, irritability, ill-temper, shaking the
head, rubbing nose, parasites in discharge. Treatment, injections,
trephining. Prevention.
This parasite has a worm-like body, but is closely allied to the mites
and belongs to the Arachnida. It differs from the mite in having but
four short limbs retractile and protractile and furnished with sharp
claws. The body is thickest toward the anterior end and prolonged and
narrow posteriorly; marked by about 90 rings; head rounded off abruptly,
mouth broadly open, with a horny lip; integument with numerous openings
or stigmata (respiratory); _male_ 7 lines long by a line broad in its
anterior part genital orifice on the front part of the abdomen in the
median line; _female_ 3 to 4 inches long, by 3 or 4 lines broad
anteriorly; genital opening at the end of the tail. _Reproduction_
oviparous.
_Habitat._ Nasal chambers and sinuses of the dog, wolf, goat, and horse.
_Pentastoma Denticulata._ The young partially developed _P. Taenioides_.
Has all the rings except the two first, garnished with fine sharp
recurved spines; legs more slender with accessory booklets; length 2
lines; breadth ½ line.
_Habitat._ Cysts in the lungs, liver, mesenteric glands, etc., of the
hare, porpoise, goat, sheep and other mammals, not excepting man.
_Development._ Leuckart found that the adult Pentastomata copulate in
the nasal chambers, as many as half a million of eggs being fertilized
in a single female; that these eggs are discharged with the nasal mucus
and falling on vegetables are taken in by herbivora; their shells are
digested and destroyed in the stomach, and the liberated embryos
perforate the intestinal walls and encyst themselves in various organs.
The encysted embryo varies from ¹⁄₅₀₀ to ¹⁄₄₀ inch in length, is rounded
and blunt anteriorly but very thin posteriorly with the tail slightly
curved toward the ventral aspect. It is several months before the feet,
cutaneous spine and generative organs are developed, and during this
period it undergoes several moultings. Finally it leaves its cyst and
may live free in the cavities in the body of its host, and if it does
not escape from the body it finally constructs a new cyst and then dies.
If the host is eaten by a carnivorous animal the liberated pentastomata
reach the nose either from the lips or pharynx and in a few months more
acquire their complete development. They must reach the nose of the
horse by their presence in the food or water.
_Symptoms Caused by the Pentastoma._ No morbid symptoms have been traced
to the young encysted condition of the parasite. Yet it would not be
surprising if their presence in large numbers in the mesenteric glands
and liver should give rise to troubles of assimilation, sanguification,
biliary secretion and the like. Frerichs says they are more common in
the human liver in Germany than echinococcus, but adds that they have no
clinical importance.
In their mature condition however they cause considerable irritation and
nasal discharge when present in large numbers. In dogs there is running
from the nose the discharge containing an abundance of the ova,
restless, fretful habits, sometimes a morbid readiness to bite, frequent
shaking of the head and rubbing of the face.
The _treatment_ would be to trephine the sinuses and inject lotions
impregnated with creosote, carbolic acid or naphtha. From the danger to
man of becoming infested it is important to ascertain the true nature of
any nasal discharge of the dog especially in countries like Germany and
Egypt in which this parasite is common.
_Prevention._ Deny raw offal of herbivora to dogs.