VERMINOUS BRONCHITIS IN DOGS. 387

VERMINOUS BRONCHITIS IN DOGS.*

By WituraMm Oster, M.D., L.R.C.P. Lond. ; Fellow of the
Royal Microscopical Society, London; Vice-President
of the Montreal Veterinary Medical Association ; Pro-
fessor of Physiology in McGill University, and in the
Veterinary College, Montreal.

Earty in the month of January I was asked by Principal
McEachran, F.R.C.V.S., to aid him in the investigation of a
disease which had broken out among the pups at the ken-
nels of the Montreal Hunt Club, and which was believed to
be of a pneumonie nature. On proceeding to the place we
found that the affection was confined almost exclusively to
animals under eight months old, and that it had already
proved fatal in several instances. At the time of the visit
only one pup was ill, presenting symptoms of diminished air
space in the chest. In order to ascertain the exact condition
of the lungs, one of the pups, which had died a day or two
previously, and had meanwhile frozen stiff, was ordered to be
sent to the veterinary college for dissection. On the follow-
ing day it was found at the autopsy that in addition to the
pnuemonia there were numerous small parasite worms in the
trachea and bronchial tubes. Knowing how subject many
of the lower animals are to bronchial strongyles, I did not
think it very remarkable that they should occur in the dog.
On referring, however, to Dr. Cobbold’s list of entozoa in-
festing the dog, I was surprised not to find a bronchial stron-
gyle mentioned, and a further search through the standard
works on veterinary medicine and helminthology proving
fruitless, I then wrote to the editors of the Veterinarvan
asking for information on the subject. They very kindly
replied in a short editorial note in the March number, stating
“that? so far as their knowledge extends “ no such cases
have been placed formally on record,” but Dr. Cobbold tells
them “that one such instance has been verbally brought
under his notice, though not in such a way as to be
thoroughly convincing.”

* Read before the Montreal Veterinary Medical Association, March 29th
888 VERMINOUS BRONCHITIS IN DOGS.

I shall proceed now to speak of the symptoms and pathology
of the disease, then give a description of the parasite itself, and
make a few general remarks,

Symptoms.—Only five of the diseased animals were seen during
life, and that rather irregularly, on account of the distance of the
kennels from the city. However, I have obtained some important
details from the keeper, and a case which was brought to the
infirmary and kept for some time was made the subject of cli-
nical study.

Among the initial symptoms disinclination for food and exercise,
together with an unsteadiness of gait, amounting in some of the

cases to a subparalytic condition of the hinder extremities, were .

the most evident. In fully half of the cases convulsions oc-
eurred. There was rarely diarrhoea or any other symptom
referable to gastro-intestinal disorder. Cough was not a promi-
nent symptom, being absent in many of the cases. When pre-
sent, it was short and husky, “not,” as the keeper said, “the
regular distemper cough.” In the case brought to the infirmary
the cough was well marked, and was dry and short. The pulse
and respirations were increased, and the temperature elevated.
Towards the close all food was refused, and even when fed the
soup given was commonly vomited. Death took place in most
instances quietly, though sometimes during a convulsion, and the
keeper noticed that the pups which lasted the longest had the
most fits. The duration of the disease ranged from three days
to a week, or even ten days. The whole epidemic lasted about
seven weeks,

Altogether fifteen couples were attacked, all of which, with the
exception of three couples of old dogs, were under eight months
old. Of the old dogs three had the disease badly, but only one
died. Of the total number affected four and a half couples re-
covered, so that twenty-one animals were lost. The dogs which
recovered are now in their usual health, though not in such good
condition as they were before.

With regard to the hygienic surroundings of the animals it
may be stated that, at present, the kennels are in an old house
which stands by itself on the government property known as
Logan’s farm, at the east end of the city. It is isolated, being
at some distance from any other building, and is situated on an
elevated ridge overlooking the Quebec suburbs.

‘The disease showed itself during a remarkably cold spell ;
indeed, for the first three weeks of the epidemic, the thermometer
was almost constantly below zero, It was first observed in two

VERMINOUS BRONCHITIS IN DOGS. 389

or three pups of four couples which were kept by themselves in
a separate room, 14 ft. by 8; the floor being covered with straw, -
which was changed every week. There was a cupboard in the
room, and in this the pups slept. This room was on the exposed
side of the house, and, according to the keeper, was always very
cold. The rest of the animals were kept in tolerably roomy
quarters, though at night, with the doors closed, I do not think
the ventilation would be sufficient. During the day they had
free access to a large yard. The food consisted of porridge and
cooked horseflesh, which were given either separately or boiled
together. They got nothing else. The oatmeal was of good
quality, nor did I find in portions of the food removed from the
feeding pans anything which afforded the slightest clue to the
origin of the disease.

Pathology—Post-mortem examinations were made in eight
cases. The following notes were dictated at the time.

Casz 1.—Autopsy eighteen hours after death. Body that of a
well-nourished, half-grown, fox-hound bitch, On opening the
thorax the lungs only partially collapse ; the lower borders of the
lobes are firm to the touch and dark in colour. The vessels in
the lower mediastinum look fall, and the tissues in that region
are blood-stained. Pericardium natural ; heart appears of normal
size; right auricle filled with dark grumous clots, which extend
into the vessels and are here deeolourised. Right ventricle dis-
tended with dark, semi-coagulated blood; the conus arteriosus is
filled with a perfectly decolourised clot, which passes into the
pulmonary artery to the third and fourth divisions. The left
auricle contains a small coagulum. The left ventricle contains
no blood, but the whole cavity is occupied by a firm milk-white
thrombus, which is connected through the mitral valve with the
one in the auricle, while a prolongation from it extends into the
aorta.

Lungs.—After normal, on inverting them, a quantity of dirty
brown frothy fluid escapes through the larynx.

The anterior and middle lobes and the anterior half of the
posterior lobe of the right lung are solidified, being of a dark
reddish-brown colour, and contrasting strongly with the unaf-
fected parts. The pleural surfaces are swooth, and there is no
exudation. On section the lung tissue is of a dark red colour,
the surface of the section finely granular, and bathed with a
quantity of reddish-brown serum. On close inspection it is seen
that the air cells are uniformly filled a solid exudation ; attempts
390 VERMINOUS BRONCHITIS IN DOGS.

atinflation of the affected portions with are unsuccessful. Portions
excised sink at once when placed in water. In the left lung the
apex of the anterior lobe, the whole of the middle, and the root
of one of the posterior lobes, are in the same condition. The
portions of the organs not diseased are of a rosy red externally,
and on section contain much blood and frothy serum. Between
the healthy and diseased parts there is a zone of intense
hyperemia.

Trachea.—On slitting up the windpipe the mucous membrane
is found covered with a dark frothy mucus. The membrane
looks pale and natural to within an inch of the bifurcation, but
at this point it becomes reddened, and uneven from the projec-
tion of irregular little masses of a greyish-yellow colour, which
on close inspection are found to be localised swellings of the
membrane, containing small parasitic worms, the white bodies of
which can be seen lying upon and partially imbedded in these
elevations. They are most abundant just at the bifurcation, at
the lower part of which several have emerged, forming an eleva-
tion three or four lines in height. About the orifices of the
second divisions these little masses are also seen, and the whole
mucous membrane of this region is deeply congested, and some-
what swollen. Very few of the worms are found lying free on
the mucous membrane; almost all of them are attached to the
masses or buried in them. The smaller tubes, especially those
leading to the diseased portions of the lungs, are filled with a
dirty brown fluid, and on squeezing any portion of the organ
quantities of it can be expelled.

The bronchial glands are swollen and enlarged.

The spleen appears healthy.

The left kidney contains a large amount of blood; otherwise
looks natural. Nothing unusual in the right one.

The stomach contains a few ounces of dark brown fluid; mucous
membrane is pale. Large veins full. .

The duodewwm contains a bile-stained mucus, and on pressing
the gall-bladder, bile flows from the papilla biliaria.

Jejunum and ilewm contain a dirty black material adhering to
the mucous membrane.

One tenia elliptica and one ascaris marginata are found in
the jejunum.

Large bowel healthy.

Liver firm, dark red in colour, lobules indistinct, hepatic veins
full, gall-bladder contains a small amount of bile. There isa
clot in the portal vein.
VERMINOUS BRONCHITIS IN DOGS. 391

Brain.~Nothing abnormal about the membranes. Substance
of good consistence and apparently healthy.
In the following cases I have condensed the original account.

Casz 2.—A five months’ old dog pup, which had been ill a week.

Extensive pneumonic consolidation of the lungs, involving the
lower part of the anterior lobe, and scattered patches in the middle
lobe on the left side, and half the posteror lobe on the right. On
section the solidified parts presented the appearance already de-
scribed in the preceding case, and the unaffected portions are in
a state of engorgement. On slitting up the trachea and bron-
chial tubes much frothy blood-tinged serum escaped, but no
trace of any parasites can be found either in the tubes or paren-
chyma of the lungs. No ova or young parasites can be found
in the blood of the cavities of the heart or of the pulmonary
artery.

Abdominal viscera appear healthy, though, owing to the ob-
struction in the lesser circulation, the blood-vessels are engorged.
‘A few ascarides in the intestine, and one small tenia elliptica.

Casz 3.—Dog pup, six months old.

In the left lung there are scattered patches of pneumonia in
the anterior lobe, one or two are in the middle lobe, and half a
dozen, the size of marbles, closely set together in the upper part
of posterior lobe. In the right lung the anterior lobe is solid
in an area 8" by 1”, extending along the lower free border, and
through the whole thickness. Small patches occur here and there
over the other lobes. In this instance the inflamed spots are
smaller, and not so extensive as in the other cases. On slitting
up the trachea the mucous membrane looks healthy to within 2”
of the bifurcation, when it becomes swollen, dark red in colour,
and thickly scattered over with the elevated granular masses
noticed in the first case, attached to and in which numerous
small white worms can be seen. A stream of water of consider-
able force does not wash them away, but shows that each little
elevation consists of a nest of the parasites. They extend to the
tubes of the second order, and are specially abundant at the
bifurcation itself, and about the orifices of the first tubes given
off from the main bronchi. The small tubes are filled up with a
frothy serum. Two of the worms are found far in the mucus.

Stomach and intestines appear healthy, except the lower
portion of the ileum, which is congested.

In this region ten specimens of dochmius trigonocephalus
occur, and furthur up in the bowel eight ascarides.
392 VERMINOUS BRONCHITIS IN DOGS.

Casz 4.—A six months’ old dog pup brought to the infirmary
and died the next day.

In the left lung the anterior and middle lobes and the lower
free border of the posterior lobe are solidified.

In the right lung the lower three fourths of the anterior and
middle lobes, and the lower fourth of the posterior lobe, are in
the same condition. Pleural surfaces involved. The posterior half
of the windpipe contains upon the mucous membrane of its lower
wall about a dozen small red patches, which extend in the axis of
the tube; some appearing like linear streaks due to the injection
of a few vessels. In all of them the presence of parasites can be
determined, though in some of the smaller only one is found.
They become more numerous about the bifurcation and in the
main bronchi, occuping chiefly the lower wall. The masses are
isolated and the mucous membrance between them intensely in-
jected. None are found in the second divisions of the tubes.

Abdominal organs contain a good deal of blood. Mucous
membrane of stomach and intestines look healthy. The large
powel contains a quantity of consistent feces. Six ascarides in
the duodenum; six specimens of dochmius trigonocephalus in
the jejunum, and ten specimens of tricocephalus affinis in the
coecum.

Blood of heart and veins examined ; nothing abnormal found.

Casz 5.—Seven months’ old bitch pup. Considerable emacia-
tion. Scattered areas of pneumonia throughout both lungs; not
quite so extensive asin Case 4, but presenting similar characters.
From an inch in front of the bifurcation of the trachea to the
bronchi of the second order, the whole mucous membrane is
transformed into an irregular greyish-yellow granular structure,
upon which the bodes of numerous white worms can be plainly
seen. Two sizes may be distinguished, one longer and of a more
opaque white, which subsequent examination showed to be the
female, the other shorter, thinner, and paler. In this case, even
about the orifices of the third division of the bronchi, a few nests
of the parasite can be seen. In the mucus from the smaller
tubes a few of the adult worms occur, and on spreading it out
on glass slips, and examining with a low power, a few ova and
free embryos are seen.

Blood of heart and veins contain no parasites.

Nothing abnormal in the stomach or intestines, a large speci-
men of tenia elliptica in the latter, also a few ascarides.

Case 6.—A thin, badly nourished dog pup, six months old,
VERMINOUS BRONCHITIS IN DOGS. 393

Lungs present numerous patches of consolidation, involving on
the right side the lower half of the anterior lobe, and a large
piece of the posterior lobe. On the left side the free borders of
the anterior and middle lobes for almost two inches from the
margin, and a broad strip along the upper part of the posterior
lobe.

Trachea and bronchi healthy ; mucous membrane of the tubes
in the affected parts congested, but no parasites in the membrane
or in the lung tissue.

Stomach and intestines appear natural; a few ascarides in the
latter. Nothing abnormal found in the blood.

Case 7.—Dog pup, seven months old. The autopsy, which
was made at the same time as the previous case, reveals a similar
condition of the lungs, and'an entire absence of any parasites
either in the tubes or in the parenchyma of the lungs. Nothing
unusual in the abdominal organs. The tenia elliptica and five
or six ascarides in the jejunum.

Cast 8.—A fine, well-grown dog pup, eight months old. Had
been ill a week.

Lungs contain pneumonic areas of considerable extent ; in the
right involving the entire apex with the dependent border, and a
small portion of the posterior lobe near the diaphragm. In the
left lung almost the whole of the middle lobe, and the root of
the posterior, are specially affected.

On opening the windpipe the discrete elevations above described
upon the mucous membrane about the bifurcation are very distinct,
and the worms can be seen in them. The appearance is very
like that met with in Case 4, and the description need not be re-
peated. No parasites in the intestines. Nothing abnormal found
in the blood.

The general and specific characters of the worm may be defined
as follows :

Strongylus canis bronchialis.—A slender nematode helminth,
body filiform, the female measuring about one fourth of an inch in
length, the male smaller, measuring one sixth to one eighth of an
inch ; head conical, mouth simple, unprovided with papille ; tail
of female obtuse, anal and generative orifices terminal, opening by
a c'oaca; ovarian tube containing one row of eggs, which, in the
mat wre species, have developed into slender-coiled embryos ; tail
of the male somewhat pointed ; penis consists of a double spiculum
of a yellowish-brown colour; mode of reproduction viviparous.

Only occasionally, as stated above, were the worms found lying
894: VERMINOUS BRONCHITIS iN DOGS,

free upon the bronchial membrane; as a rule they lay imbedded
in a localised granular swelling of the mucosa, from which portions

  

Fia. 1-—Head of male worm. Fre. 2.—Tail of female worm,
: showing the young embryos.

of them protruded. They could readily be pulled out witha pair
of fine forceps, but a stream of water did not wash them away.

“In several of the cases examined (more especially Case 4) the
whole mucous membrane of the affected part appeared rough and
irregular, as if ulcerated, and innumerable parasites lay upon and
in it. The mature females could easily be distinguished, not only
by their larger size, but by the opaque whiteness of their bodies.
The majority of the female worms examined were immature, and
did not contain developed ova. The males were not nearly so
numerous as the females. Forms intermediate between the adult.
worms and the young embryos (some of which, as already men-
tioned, existed free in the mucus) were not met with.

The occurrence in the bronchial tubes of the lower animals of’
nematoid worms belonging to the genus sirongylus is by no means
uncommon. Owing to the irritation caused by their development
in the mucous membrane an inflammation of the tubes is produced,
hence the affection is known by the names of parasitic or yermi-
nous bronchitis popularly called “husk” or “hoose.” It is not
altogether unkn wn in man, but very few instances are on record.
Infesting the domestic animals there are three well-recognised
species of strongylus: the 8. filaria of the sheep and goats; S.
paradoxus of the pig, and S. micrurus of the calf, more rarely of
the horse and ass. In calves and lambs parasitic bronchitis often
constitutes a serious and fatal epidemic, so much so that in the
latter it goes by the name of the lamb disease. So far as I know,
no epidemic of the kind has been noticed in Canada. The species
I have here described differs in several particulars from either of
the above mentioned, and is most probably new to science.
VERMINOUS BRONCHITIS IN DOGS. 895

The origin of the epidemic must, I am afraid, like that of so
many other diseases, remain obscure. We have absolutely nothing
to aid us in forming an opinion on the subject. There had been
no change in the locality nor in the food. The straw upon which
the dogs slept was of the ordinary kind, and the usual attention
had been paid to changing it and also to the general sanitary con-
dition of the place. The disease broke out, too, during a spell of
very severe weather, when the food left in the pans froze quickly:
The course of the epidemic was short, lasting between six and
seven weeks, a sufficient time, however, to destroy almost all the
pups in the kennels.

The mode of invasion in parasitic disease of the bronchial
tubes has been, and still is, a matter of much dispute, some
observers maintaining that “the ova and young parasites taken up
with the food, in the first place gain access from the alimentary
canal to the circulation ;” others hold the view that they pass
directly from the mouth to the trachea, or that the ova are inhaled
by the breath. The former view is the one most generally enter-
tained, and it is urged in its favour that the presence of the worms

. has been determined in the cavities of the heart and in the blood-
vessels, as well as in the intestines. Now, in the epidemic under
consideration I think this view does not meet the case. Supposing
the young embryos to have been ingested and to have gained
access to the branches of the portal vein, they would then be
carried to the right side of the heart, and from thence to the
lungs, by the pulmonary artery, the capillaries of which ramify
in the lung substance alone, a situation in which the parasites did
not occur. To get to the bronchial mucous membrane they must
be returned by the pulmonary veins to the left side of the heart,
enter the aorta, and pass out by the small bronchial arteries
which supply the tubes—an exceedingly round-about and some-
what improbable route. It is to be remembered that young
strongyles have been found capable, like many other nema-
toid worms, of reviving on the application of moisture after
a dessication of a month or more, and even after immersion in
spirits of wine, and solutions of corrosive sublimate and alum
(Williams), so that their chance of survival under adverse circum-
stances is unusually good. It seems quite as reasonable to
suppose that the dried embryos were inhaled with the breath, and,
lighting in the mucous membrane, found suitable conditions for
development. The position of the parasites about the bifurcation
of the trachea, at the angles of division of the main bronchi, and
most abundantly in the lower wall of the tubes, just the localities
896 VERMINOUS BRONCHITIS iN DOGS,

where small particles would be most likely to lodge, favours an
infection through the air rather than by the blood. The negative
evidences in the heart and blood-vessels do not go for much either
way, a8 the examination in all the cases was made after the
invasion of the parasites, and consequently at a time when they
could scarcely be found in the circulation.

It is a somewhat remarkable fact that verminous bronchitis
prevailed to a much greater extent, and is more fatal in young
animals than in adults. Thus lambs and calves are the chief
victims in epidemics of “hoose,” whereas it is only occasionally
that adult animals succumb to the disease. In lambs the worms
are usually found in the bronchial tubes, while in sheep they are
more commonly encysted in the lung tissue itself, where they do
not appear to cause much irritation. It seems to me that in the
anatomical peculiarities of the lungs in young animals we have
an explanation of the fatality of the disease among them. If the
bronchial tubes of a young animal be compared with those of an
adult they are seen to be softer, much less rigid; the mucous
membrane is lower, not so thin, nor so closely attached to the
tissues beneath. Hence it happens that in inflammation of the
tubes from any cause, swelling and tumefaction of the mucous
membrane readily occur, and constitute elements of danger which
are directly proportionate to the calibre of the tubes attacked.
In the cases above reported the swelling of the membrane in the
larger tubes was considerable, and, though not sufficient to
prevent the access of air, must have interfered greatly with the
expulsion of mucus from the smaller tubes, not only by decreas-
ing and narrowing the orifices of exit, but also by destroying,
over an important area, the ciliary action so useful for this purpose.
The same difference is met with in human practice. Ordinary
acute bronchitis in the adult is not at all a dangerous affection,
while in young children it is the reverse ; and for the very reason
that in them the bronchial mucous membrane swells easily, and
there is not the same expulsive power to enable them to get rid
of the mucus which, in consequence, accumulates, and may cause
collapse or inflammation of the lung tissue. In the “lamb disease”
death occurs from asphyxia, caused by the collection of mucus
in the tubes. I have no records at hand of the state of the lung
tissue in these cases, whether it is in a condition of collapse or of
inflammation ; probably the latter, for I see the expression, ver:
minous pneumonia,”’ used by some authors.

With reference to the pneumonie condition of the lungs of
the dogs in this epidemic, it will be remembered that in three of
THE PRINCIPLES OF BOTANY. 397

the post-mortem examinations the inflammation of the lungs was
found without the occurrence of parasites in the bronchial tubes ;
the pneumonia being quite as extensive as in the cases accom-
panied with strongyles. I must confess that this circumstance
has puzzled me not a little, and I see no very satisfactory expla-
nation of the fact. It appears natural to refer the diseased con-
dition of the lung substance in the parasite cases to the accu-
mulation of the mucus in the smaller tubes producing collapse
of the air cells in certain areas, which subsequently became in-
flamed—a sequence of events sometimes observed in children.
The appearance of the lungs in several of the cases corresponds
with this view ; for the pneumonia was lobular, affecting small
and isolated portions of the lung tissue.