NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
V. R. RAJAGOPALAN & V. R. GOPALAKRISHNAN 303
of carbolised saline was added and the growth was displaced with the help of
platinum loop or preferably with a capillary pipette having a little curve at
the tip. For convenience, it is better to have the least required quantity of
carbol saline. In the process of emulsification it was invariably found that
the culture adhered to the loop and moved about in a stringy form with out
detaching itself from the loop in spite of smart shaking. Hence a capillary
pipette was found better for reasons stated below.
The saline suspension was transferred to a sterile mortar. Along with
the suspension a small length of the narrow portion of the capillary tube in-
cluding the curved end was crushed with the pestle so that the fine pieces of
of glass aided in breaking up the strands or flocculi. After about ten minutes
trituration, a uniform emulsion was obtained. For the removal of the glass
particles, the solution was centrifuged for three minutes at 1,000 R. P. M.
The supernatant fluid was removed and the opacity standardised for the test.
It was found that the antigen prepared as above, remained quite stable.
The agglutination test was carried out by the usual macroscopic method.
Serum was put up in a series of six dilutions from 1/25 to 1/800. The bac-
terial suspension was added and the test was conducted in the waterbath at
55°C. and the readings were taken at the end of 4 and 24 hours. The
homologous titre (mouse organism) was found to be 400. The next step was
to find out whether the organism possessed any serological relationship, and
if so the degree, with the other members of the Pasteurella group. The serum
was submitted to cross-agglutination test against eleven different antigens
(Table II).
TABLE II
Serum
Mouse
organism
(Rabbit
99)
„
„
„
„
„
„
„
„
„
„
„
Antigen
Mouse
organism
Past. 2 .
„
18 .
„ 22 .
C. 9 .
C. 10 .
C. 11 .
C. 17 .
C. 18 .
C. 19 .
C. 20 .
C. 21 .
1/25
C
—
—
P
—
—
—
—
—
—
—
—
1/ 50
C
—
—
P
—
—
—
—
—
—
—
—
1/100
C
—
—
—
—
—
—
—
—
—
—
—
1/200
C
—
—
—
—
—
—
—
—
—
—
—
1/400
P
—
—
—
—
—
—
—
—
—
—
—
1/800
. .
—
—
—
—
—
—
—
—
—
—
—
C
. .
—
—
—
—
—
—
—
—
—
—
—
Result
400
(Homolo-
gous)
—
—
50
—
—
—
—
—
—
—
—
H
304
Pasteurellosis in White Mice
From the above table it is evident that the organism bears some serolo-
gical relationship with Past. cuniculicida but there was no reaction with strains
of Past, pseudotuberculosis rodentium.
TABLE III
Cross-test
Serum
C. 9 .
C. 10 .
C. 11 .
C. 17 .
C. 18 .
C. 19 .
C. 20 .
C. 21 .
Healthy
rabbit
Antigen
Mouse
organism
„
„
„
„
„
„
„
„
1/25
—
—
—
—
C —
C
—
1/50
—
—
—
—
C
—
C
—
1/100
—
—
—
—
C —
C
—
1/200
—
—
—
—
P
—
P
—
1/400
—
—
—
—
—
—
—
—
1/800
—
—
—
—
—
—
—
—
C
—
—
—
—
—
—
—
—
Result
—
—
—
—
200
—
200
—
TABLE IV
Agglutination absorption test
C. 19 absorbed by homologous
organisms . . .
C. 21 absorbed by homologous
organism . . .
Mouse organism. .
No titre
No titre
Cross agglutination test (Table III) with eight antisera for Pasteurella
pseudotuberculosis rodentium against the mouse organism suggested that two
of our stock strains, viz., C. 19 and C. 21 showed group identity. To obviate the
possibility of intercurrent acquired immune agglutinins in the sera of the rab-
bits used for the two strains cited above, agglutinin absorption tests (Table
IV) eliminated in toto the possibility of existence of antibodies other than those
of the organism under reference.
Schutze [1928] discovered agglutination affinity between a strain of
Past. pseudotuberculosis rodentium and certain members of the Salmonella
group (S. aertrycke, S. abortus equi, etc.) the relationship being confined to the
" O " antigen. Significant as this finding appears to be, since it reveals close
relationship between two different genera, the tests as shown in Table V were
carried out to see whether such affinity exists.
V. R. RAJAGOPALAN & V. R. GOPALAKRISHNAN 305
TABLE V
Cross-agglutination
Serum
Mouse
organism
„
S.
aertryeke
S.
gallinarum
Antigen
S. aertryeke
S. gallina-
rum.
Mouse
orgamsm
„
½
—
—
—
—
¼
—
—
—
—
⅛
—
—
—
—
1/16
—
—
—
—
1/32
—
—
—
—
1/64
—
—
—
—
1/128
—
—
—
—
1/256
—
—
—
—
C
—
—
—
—
Result
—
—
—
—
DISCUSSION
It would be necessary here to state briefly the various known criteria for
the classification of the organisms commonly brought under Pasteruella group
to enable us to type the one under study. Organisms classified under this
large biological group possess certain common characters although a great
difference of opinion exists among workers as to their analogy. Thus Hueppe
[1886] and other subsequent workers stated that the organisms of the Pasteur
ella group isolated from different animals possess similar biological characters
and hence believed that they were all variants of one basic type. Mention
has been made by Tanaka [1926] that insufficient difference exists between
the members of the group. However, attempts have also been made to
subdivide the group into two or three distinct types.
Jones [1921] distinguished three different types among sixteen bovine
pasteurella strains on the basis of the carbohydrates fermentation reaction
and serological tests.
On the other hand, Roderick [1922] studied the morphological, cultural,
biochemical and immunological characters of the group and came to the
conclusion that the group was composed of two distinct types, namely, (1) a
bovine-swine type affecting cattle and hogs ; (2) an ovine-avian-rabbit-cavia
type infective to sheep, birds, rabbits and guinea-pigs.
Lal[1927] found that the organisms of the Pasteurella group, tested serolo
gically, show a certain amount of group specific reaction, B. lepisepticum being
an exception.
Cornelius [1929] in an attempt at serological classification observed that
out of twenty-six strains, it was possible by means of the agglutinin-absorp¬
tion test, to group seventeen strains into four groups ; the remaining seven
defied classification.
306
Pasteurellosis in White Mice
Yusef [1935] employed the precipitation test to overcome certain obvious
difficulties in the agglutination test. He established three serological groups
in dealing with most of the strains used previously by Cornelius (loc. cit), and
discussed certain unaccountable discrepancies when comparing his results with
the findings of the previous worker.
Smillie [1920] isolated Pasteurella organisms in wild rats. Attempts to
correlate the above by serological methods with Past. pestis, were
unsuccessful.
Thus it is apparent that the species specificity of the known members of
of the pasteurella group still remains unsettled. This is, perhaps, one of the
reasons why Topley and Wilson [1937] have stated that " there is still a disposi-
tion to treat the Pasteurella group as a convenient refuge for any small,
gram-negative bacillus whose identity has not been accurately ascertained ".
Conflicting as the opinions are in regard to classification, they are sufficient
to emphasise the fact that a very close relationship exists between these or-
ganisms and to demonstrate their distinct characters, if they do exist, most
delicate and reliable serological tests must be employed. A further difficulty,
however, in the way of serological study of these organisms arises from the fact
that they are but poor antigens, both for the excitation of antibody produc-
tion and for serological reaction in vivo.
In view of the opinions stated in the foregoing paragraphs, it would seem
that there is sufficient evidence to show that the mouse organism possesses the
common characters of the Pasteurella group. As regards its type, the mor-
phological, cultural, and biochemical characters indicate that it is similar to
Pasteurella muricida, Meyer and Batchelder [1926]. They have described in
detail the tests of 34 strains of rat pasteurella obtained in the course of plague
control work in Oakland and Alameda. They observed that maltose was
seldom split by fresh strains while old cultures repeatedly acquired the
property of fermenting it. But the organism under study fermented mal-
tose in about 24 to 48 hours. Such variations, however, are not uncommon
and are likely to appear within the boundaries of any species or strain.
The stalactile formation observed was suggestive of similarity with
Past. petis but this was ruled out by the absence of capsule formation and abi-
lity to ferment sucrose.
In discussing its relationship with Past. pseudotuberculosis rodentium
it would seem necessary to go a little further in detail. The mouse pasteurella
possesses the character of true animal pasteurella in its ability to ferment suc-
rose—a character sometimes exhibited by Past. pseudotuberculosis ro-
dentium strains [Topley & Wilson, 1937]. It is also non-motile but again Past.
pseudotuberculosis rodentium Group III is non-motile to which the organism
under study appears to have some cultural similarity but no serological affi-
nity. The absence of cross titre between mouse serum and Past. pseudotu-
berculosis rodentium antigens as compared with the demonstrable agglutination
V. R. RAJAGOPALAN & V. R. GOPALAKRISHNAN 307
reaction between Past. pseudotuberculosis rodentium sera and mouse pasteurella
antigen, similar to that observed by Smillie (loc. cit), seems curious but not
unaccountable.
SUMMARY
An outbreak of rodent septicaemia in white mice, maintained for experi-
mental purposes at the Imperial Veterinary Research Institute, Mukteswar, is
described.
The causal agent—a member of the Pasteurella group was subjected to a
detailed study. It was found to be culturally, morphologically and biochemi-
cally very closely related to or probably identical with Pasteurella muricida
[Meyer and Batchelder, 1926].
A comparative serological study of the organism with some strains of
Pasteurella in our stock and their relationship are also discussed.
This appears to be the first record in India of the occurrence of Pasteurella
muricida as the cause of an epizootic among rodents.
REFERENCES
Cornelius, J. T. (1929). J. Path. Bact. 32, 355
Hueppe, F. (1886). Berl. Klin. Wsck. 23, 776
Jones, F. S. (1921). J. A. V. M. A. 60, 271
Lal, R. B. (1927). Amer. J. Hyg. 7, 561
Meyer, K. F. and Batchelder, A. P. (1926). J. Inf. Dis. 39, 386
Roderick, L. M. (1922). J. Inf. Dis. 31, 313
Schutze, H. (1929). Syst. Bact. Med. Res. Coun. 4, 474
Smillie, W. G. (1920). J. Inf. Dis. 27, 378
Tanaka, A. (1926).
ibid,
38, 421
Topley, W. W. C. and Wilson, G. S. (1937). The Principles of Bact. & Immunity, 2nd
Ed.
Yusef, H. S. (1935). J. Path. Bact. 41, 203
THE IMPORTANT HELMINTH PARASITES OF HORSES—
THEIR TREATMENT AND CONTROL*
BY
HAR DAYAL SRIVASTAVA, M.Sc., D.Sc.
Helminthologist (On Special Duty)
Imperial Veterinary Research Institute, Mukteswar-Kumaun
(Received for publication on 1st November 1938)
(With Plates XXIV and XXV)
NOTWITHSTANDING the mass of literature published in recent years,
the economic importance of the helminth parasites of the horse is often not
fully realised by the horse owner. This lack of appreciation is mainly due
to the fact that helminthiases, unlike bacterial and virus diseases, are seldom
spectacular in their onset and symptoms. The common symptoms of helmin-
thiases—a prolonged and progressive, afebrile unthriftiness gradually result-
ing in death—are often overlooked or are attributed to some other cause.
But, there are reasons to believe that more damage is done to the general
health of horses in India by worms than by all the other causes of disease
combined. The usual symptoms of helminthic infestation in the horse are
unthriftiness, emaciation, tucked up flanks, distended or pendulous abdomen,
rough coat, pallor of the visible mucous membranes and in some cases frequent
colic and diarrhœa. The animal usually feeds well, shows no rise in tem-
perature but is unable to do the normal amount of work because it gets tired
quickly when put to work. Parasites are especially damaging to young
and growing animals, in which they produce stunting and lack of develop-
ment. Considerable damage is done by the wanderings of the larvae through
the various organs of the body before they reach their seat of predilection to
attain maturity. At times a horse in good bodily condition may die suddenly
of grave verminous thrombosis and embolism of the mesenteric artery. It
is the common experience of horse owners that when horses infested with
worms are treated they improve considerably in weight and condition. Foals
when free from parasites have been reported to weigh a hundred pounds more
than others of the same age but infested with worms.
The horse is a host to a number of worms and the infestation is often
so heavy and varied that this animal may be regarded as a helminthological
museum. The helminth parasites of the horse show a wide variation in
* This is the second of a series of popular articles by the author on the helminth parasites
of domestic animals—their treatment and control.
( 309 )
310
Important Helminth Parasites of Horses
structure, size, habits, life-history and in the degree of harm they cause to
the host. In order to keep the horse in sound condition it is necessary to pay
sufficient attention to its parasites. In this paper the parasites of the greatest
importance are discussed in more detail than those of less importance ; and
only those methods of treatment which have been found to be effective
against the parasite or parasites involved have been recommended. In
literature a large number of drugs have been recommended for the treatment
of helminth parasites of the horse. Any one of them, when given in suffi-
ciently large quantities, may result in the expulsion of some of the parasites
present, but to make the treatment as effective as possible it is essential to
choose the right drug from the large number of anthelmintics available for
administration.
All the three main groups of helminths, flukes, tapeworms and round-
worms are found in the horse, and often in large numbers too. The flat-
worms, comprising flukes and tapeworms, of the horse are relatively un-
important, but the round-worms are very important and are responsible for
most of the damage.
FLUKES
Only a few species of flukes occur in the horse, though several forms
which normally occur in other hosts have been reported as accidental para-
sites. The common liver fluke of ruminants may at times infest the horse.
Liverfluke disease in equines appears to be rather rare. However, in cases
where treatment is considered necessary carbon-tetrachloride may be used
with safety to adult horses in doses of 25—30 c.c. Specimens of liverflukes
may be found in a typical foci, such as lungs, under the skin and other situa-
tions. Prevention consists in keeping horses off low and swampy pastures.
specially in localities where the disease is known to be prevalent; besides
the common control measures directed against liverflukes.
The large and small intestines of the horse are frequently heavily in-
fested with amphistomes, but little is known with regard to the pathogeni-
city of these parasites, which are generally considered to be unimportant.
The life-history is probably similar to those of other amphistomes. Carbon-
tetrachloride or tetrachlorethylene are the drugs indicated. Prevention
is the same as for the liverfluke.
A few species of blood flukes are known to parasitize the horse, the
commonest being Schistosoma indicum, which occurs in the portal, pancreatic,
pelvic, hepatic and mesenteric veins of its hosts. The eggs are normally
discharged into the intestine and pass out with the faeces. As is the case
with all flukes an intermediate molluscan host is intercolated in the life-
cycle. The cercariae actively penetrate into the body of the final host.
The affected animals become anaemic, lose condition and the normal functions
of the intestine may be deranged due to bilharzial enteritis. The most im-
portant clinical manifestation of the infestation, however, is a peculiar form
of nodulated hepatic cirrhosis, associated with intractable debility. This
H. D.
SRIVASTAVA
311
nodulated cirrhosis is produced by the deposition of the ova in the liver.
Positive diagnosis depends on the finding of the characteristic ova in the
faeces of the host. As the adult parasite inhabits the vascular system, in-
travenous administration of tartar emetic or antimosan is indicated. The
treated animals should be prevented from acquiring fresh infestation. The
common control measures in fluke infestation should be adopted, such as,
proper disposal of excreta, destruction of the intermediate host and the
keeping the animals off the sources of infection.
TAPEWORMS
Horses are known to harbour three species of tapeworms of the genus
Anoplocephala. The large, A. magna, and the dwarf, A. mamillana, horse
tapeworms usually occur in the small intestine and may occasionally be
found in the stomach. The third species—A. perfoliata—which is inter-
mediate in size between the large and the dwarf tapeworms, occurs usually
in the caecum and is also found in the lower portion, rarely the upper portion,
of the small intestine. The life-history of Anoplocephaline cestodes is not
yet definitely known, though it is widely believed that some invertebrate
intermediate host is involved. Recently some American workers have adduced
evidence to show that in the life-cycle of an allied genus—Moniezia—which
is parasitic in ruminants, a free living mite—Galumna sp.—serves as an inter-
mediate host.
Light infestations of tapeworms in horses produce no symptoms but
heavily infested animals may suffer from intestinal catarrh and show digestive
disturbances, unthriftiness, a shaggy coat and anaemia. The last mentioned
species—A. perfoliata—occurs in large numbers and produces small inflammed
areas and ulcers of the mucosa at the seat of attachment. At times it may
rupture the wall of the caecum. Tapeworm infestation can be diagnosed
by finding the ripe proglottids or eggs in the faeces of the animal.
Very little definite information is available regarding the treatment of
tapeworms in horses. The following drugs have been frequently employed
with good results:
Oil of turpentine is effective when given in a dose of 60 c.c. in capsule,
followed every second day by 30 c.c. in capsule, until five or six doses have
been administered. The last dose is immediately preceded or followed by
a quart of raw linseed oil. A mixture of 60 c.c. of turpentine and 8 c.c. of
extract of male fern in a litre of raw linseed oil is often found to be useful
in the case of the adult horse, when given after fasting the animal for 24 to
36 hours.
Freshly ground areca-nut in doses of from 30 to 45 grm. may be
given in capsules, after starving the animal for 24 to 36 hours. It has a
purgative action, but if the bowels do not move within four to five hours
one to two pints of raw linseed oil should be administered. It is contra-
indicated in cases of very young or old and emaciated animals.
I 2
312
Important Helminth Parasites of Horses
Kamala may be administered in capsules of 30 grm. to adult horses
after the animal has been fasted for 24 to 36 hours. The drug has a
purgative action and seldom needs to be followed by a purgative. It
should not be given to very young or old and weak animals or those suffering
from febrile diseases, such as influenza, strangles and infectious anaemia.
Oleoresin of male fern may be given to adult horses in doses of 3 to 6
drm. (10 to 20 grm.) in capsules after fasting the animal for 24 hours.
It should be immediately preceded or followed by a quart of linseed oil.
All these drugs should be given to animals in good condition which can
presumably withstand their effects.
No definite prophylactic measures can be formulated until the life-history
of the parasite has been established. However, proper disposal of excreta
in which mature segments and eggs are voided should be practised, as suggest-
ed in the case of round-worm infestation.
ROUND-WORMS
Of the helminths infesting the horse, round-worms are by far the most
common and important. These vary considerably in their size, structure,
biology and injuriousness. For the completion of the life-cycle some of these
require an intermediate host in which they undergo a part of their develop-
ment, while other species are transmitted from one animal to another directly
by eggs or by their infective larvae. The majority are transmitted directly,
without the agency of an intermediate host. Some of these worms are blood
suckers, others do damage in various ways : all of them probably tend to
produce unthriftiness, in some cases going on to cachexia.
ASCARIDS
The large intestinal round-worm—Parascaris equorum—is a large
yellowish worm, sometimes a foot long, which is often passed in the droppings.
It inhabits usually the upper part, occasionally the middle and lower parts,
of the small intestine. At times they are found in the caecum and the stomach.
The infestation may be heavy and is particularly harmful to foals and young
horses.
Eggs are produced in large numbers by the female worms and are voided
with the faeces. They are very resistant to adverse conditions, like drying
and freezing and to chemicals, and may remain viable for several years, but
hot dry conditions destroy them in a few weeks. The thick egg-shell protects
the contained larva against various unfavourable influences. Ordinarily
sufficient moisture is present in horse manure for the development of the
eggs. Droppings which appear dry on the surface usually contain enough
moisture in the middle to permit normal development of these eggs. Under
suitable conditions of temperature and moisture the eggs develop to the in-
fective stage in about two weeks. They do not hatch and the infective larvae
remain inside the egg-shell until they reach the gut of the host.
PLATE XXIV
[ Ind. Jour. Vety. Sci. & Anim. Husb., Vol. IX, Part III
FIG. 1. Ascarids journey through the body of the horse (After Schwartz, Imes and Wright)
FIG. 2. Life-cycle of the horse ascarid—Ascaris equorum (After Schwartz, Imes and Wright)
PLATE XXV
[ Ind. Jour. Vety. Sci. & Anim. Husb., Vol. IX, Part III
FIG. 1. Life-cycle of one of the blood strongyles
(After Schwartz, Imes and Wright)
FIG. 2. Section through the wall of the large gut
showing the head of an attached, blood
strongyle (After Wretzel)
FIG. 3. Life-cycle of the large stomach worm - Habronema muscae (After Schwartz, Imes and Wright)