NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
106 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I
This fluke has been recorded a number of times from horses in India. Cobbold
[1875] examined the material sent to him by Collins from horses in India and desig-
nated it as Amphistoma collinsi. Some time later he received another instalment
of three worms from Professor Simonds, which were collected by Stanley in India.
These latter he named Amphistoma stanleyi, remarking at the same time that
"This is apparently nothing more than the large variety of the above ?". Cob-
bold, however, did not give any adequate account of the worm. Stiles and Gold-
berger [1910] published an elaborate account of these, although the material at
their disposal was very little. They, however, agreed with Cobbold in retaining
the two species : P. collinsi and P. stanleyi. Maplestone [1923] made a detailed
comparative study of these worms and arrived at the conclusion that the species
P. collinsi and P. stanleyi are identical, the difference recognised between these
two species by Stiles and Goldberger being due to the difference in age of the two
specimens. Fukui [1929] also is in entire agreement with Maplestone in regard
to the synonymy of P. stanleyi with P. collinsi. I have at my disposal a large
number of these worms, both immature and fully mature, collected from horses
at Muktesar and a study of these leads me to corroborate Maplestone's view
regarding the synonymy.
I have recently had an opportunity of examining some collections from Indian
elephants in Madras, Assam and Burma, which on close examination proved to be
P. collinsi. Although the presence of these worms in horses, as will be appar-
ent from the foregoing remarks, is very common in India, its occurrence in elephants
has not been recorded up to the present time. Although the parasite, P. collinsi,
has been quite well described by Stiles and Goldberger, it is thought desirable
to describe here the material from a different host, so that no confusion may arise
in future in regard to the identity of the worm.
The material for study consists of about two dozen specimens obtained from an
elephant in Madras, numerous specimens of medium size and about a dozen and
half specimens of large size obtained from an elephant in Assam and about half a
dozen specimens obtained from an elephant in Burma.
Description.—The body of the worm is 5.7—12.5 in length, 3—7 in breadth and
2.5—3.5 in thickness. The spirit preserved specimens appear to be of flesh colour,
while those preserved in formalin are whitish in colour. They are oval in shape,
convex dorsally and flattened on the ventral surface. The larger specimens have
their ventral surface concave. The anterior extremity is bluntly pointed and
bears on it bluntly pointed, slender papillæ. The posterior extremity is bluntly
rounded, being almost semicircular and the lateral margins are convex. The geni-
tal pore is situated at 2.5—4.7 from the anterior end, approximately midway
between it and the anterior margin of the posterior sucker. This latter is situated
TREMATODE PARASITES OF INDIAN ELEPHANT
107
ventrally in front of the posterior end and is surrounded by a prominently raised
margin. Its diameter varies from 1.34 to 2.11.
The mouth is situated at the anterior extremity and is 0.34—0.57 in diameter.
It is surrounded by an oral sucker constricted in the middle. The constriction
divides the sucker into two portions: a globular oral portion measuring 0.73—
0.97×0.43 and the posterior œsophageal or bulbous portion measuring 0.7—1.1
longitudinally and 0.64 —1.36 transversely. The bulbous portion is bilobed and
each of the bulb communicates posteriorly with a pouch measuring 0.98—1.57 ×
0.7—1.27. The œsophagus starts from the base, between the two bulbs of the
oral sucker and passes posteriorly in a straight course. Its walls appear to be
glandular and it measures 0.93—1.62 in length. It bifurcates into two intestinal
cæca passing posteriorly and ending somewhat posterior to the middle of the pos-
terior sucker. Each cæcum makes an inward bend at the level of the testes.
The excretory bladder lies on the dorsal surface of the posterior sucker and
the excretory pore opens in the central line behind the posterior sucker, at a dis-
tance of 0.42—0.84 from the posterior extremity.
The testes are two large, deeply lobed cauliflower-like bodies situated slightly
posterior to the centre of the body. They measure 1—2.48 × 0.73—2.28. The
position of the testes in the body appears to be variable : being sometimes slightly
anterior, and sometimes slightly posterior. The vasa efferentia arise from the centre
of the testes and run anteriorly for a short distance where they unite with each
other centrally and from a vesicula seminalis. This latter is a thin-walled, mode-
rately dilated, but much coiled duct. It passes into a relatively thicker muscular
duct called the pars musculosa. This is not so much coiled as the vesicula semi-
nalis. Usually a few of the coils of the pars musculosa pass anterior to the
genital opening. Following the pars musculosa is a short, narrow duct called the
pars prostatica which is surrounded by a few noncellular glands. From its ventral
aspect there passes ventrally a short, muscular duct, the ductus ejaculatorius,
which unites with the terminal portion of the uterus, the metraterm, to form a
ductus hermaphroditicus. This latter is a very short canal opening into the geni-
tal atrium which communicates ventrally with the genital pore. The ductus har¬
maphroditicus, the ductus ejaculatorius, metraterm and the genital atrium are
enclosed in a mass of muscle fibres.
The ovary measuring 0.42—0.87 × 0.27—0.74 is situated sometimes on the
left and sometimes on the right side of the middle line, between the testes and the
posterior sucker. Occasionally the ovary appears to be lying exactly in the centre
of the body. It may therefore be inferred from this that the normal position of
the ovary is central, but according as the worms have undergone contraction it
may be deflected either to the right or the left side like some other species of
108 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I
trematodes, e.g., Tremiorchis ranarum. Not unlike the testes, the position of the
ovary also varies a little, being sometimes situated somewhat anteriorly, and some-
times posteriorly. The oviduct arises from the posterior aspect of the ovary and
passes to the dorsal side where it becomes surrounded by the shell-gland. This
latter lies on the postero-central aspect of the ovary and measures 0.16 × 0.18—
0.54—0.62. Laurer's canal arises from the oviduct and passes postero-dorsally.
Its opening is 2.4—3.5 from the posterior end and approximately 2—2.66 anterior
to the opening of the excretory duct. The vitelline glands consist of sparsely
scattered follicles lying on the outer side of the intestinal cæca. Some of the
follicles also overlap the intestinal cæca and posteriorly they even appear in
the intracæcal zone, abutting on the antero-lateral sides of the posterior
sucker. Posteriorly the follicles extend as far as the ends of the intestinal
cæca, but occasionally a few follicles are found to be present even behind
these. Anteriorly also the extent of the vitelline follicles show some vari-
ation. In some cases they extend only as far as the level of the intestinal fork,
while in others they extend anteriorly as far as the hinder ends of the suctorial
pouches or the middle of the œsophagus. The uterus starts from the ventral
aspect of the shell-gland and the coils pass to the opposite side of the ovary, thence
in front, centrally, in a somewhat zigzag manner into the metraterm, which joins
ultimately with the ductus ejaculatorius and forms the ductus hermaphroditicus.
In all the cases I examined, excepting a few specimens from Assam the ova
were seen, and these measure 0.125—0.158×0.085—0.088.
Host.—Elephant.
Location.—Colon,
Pseudodiscus hawkesi (Cobbold, 1875).
Synonymy.—Amphistoma hawkesii Cobbold, 1875.
Pseudodiscus hawkesi Sonsino, 1895.
Watsonius ornatus (Cobbold, 1882).
Amphistoma ornatum Cobbold, 1882.
Pseudodiscus ornatus Sonsino, 1895.
Amphistoma hawkesi Piana & Stazzi, 1900.
Hawkesius hawkesi Stiles & Goldberger, 1910.
Watsonius ornatus Railliet & Henry, 1912.
Pseudodiscus watsoni Conyngham, 1904.
Cladorchis watsoni Shipley, 1905.
Gastrodiscus watsoni Verdun, 1907.
Paramphistomum watsoni Manson, 1908.
Watsonius watsoni Stiles & Goldberger, 1910.
Watsonius macaci Kobayashi, 1915.
TREMATODE PARASITES OF INDIAN ELEPHANT
109
The material for study consists of numerous specimens collected in Madras
and about a dozen collected in Assam.
The worms are conical with the anterior end tapering and the posterior end
hemispherical. The dorsal surface is convex, while the ventral one is excavated.
Very rarely are the worms to be seen flat ventrally as described by Fukui [1929,
234]. The position of the genital pore appears to be in a pit on the ventral surface,
but occasionally the genital papilla is seen to be slightly protruding out of the
ventral surface.
The digitiform papillæ described by Stiles & Goldberger [ 1910, 200] were seen
in all cases.
In the majority of cases were the intestinal cæca seen to end in the equatorial
zone of the posterior sucker, but in a few instances it was observed that the left
cæcum ends somewhat anteriorly.
The testes are one behind the other and in a few cases their zones are slightly
overlapping, but the condition represented by Fukui's figure 23, p. 235, was never
seen. In the majority of cases the genital papilla was not very prominent, but in
a few cases it appeared to be quite prominent.
Fukui remarks that Stiles and Goldberger were dealing with immature speci-
mens. I have at my disposal a large number of mature specimens and a few im-
mature ones. My specimens agree more with those of Stiles and Goldberger than
with those of Fukui.
Maplestone [1923, 165 ] has raised a very important issue regarding the syno-
nymy of the species P. hawkesi and P. watsoni. He was of the opinion that the two
species were identical but he abstained from giving any final verdict about them
since he was not in possession of either of the species. Kobayashi [1915] recorded
Watsonius macaci from Macacus cynomolgus and the same author [ 1920 ] gave a
description of the worm remarking in a foot note that it is very probable that the
species is identical with Watsonius watsoni described by Railliet, Henry and Joycux
[ 1912 ]. Recently Fukui [ 1929 ], who has had an opportunity of studying a few
specimens of P. hawkesi, has remarked that all the three species: P. hawkesi,
P. macaci and P. watsoni, are valid and he distinguishes them with the following
key :—
Length of oral sucker about 1/5 body length ; diameter of posterior sucker
about 1/10 body length
.
P. watsoni.
110 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I
Length of oral sucker about 1/15 body length; diameter of posterior
sucker about 1/5 body length
P. macaci.
Length of oral sucker about 1/7 body length, diameter of posterior sucker
10/25 body length
P. hawkesi.
The points of difference raised above for distinguishing the three species are
more apparent than real, based as they are on the observation of a limited number
of specimens and the conclusions drawn from them are necessarily fallacious.
With a view to test the validity of the inferences drawn by Fukui data on the
lines suggested by him were obtained from 14 specimens, the result of which is
tabulated below :—
Total length of body
Length of oral sucker/
Total length
Diameter of postorior sucker/
Total length
1
5.7
0.42/5.7=1/14
1. 33/ 5. 7= 1/ 4
2
5.2
0.33/5.2=1/16
1. 25/ 5. 2=1/ 4
3
6.2
0. 52/ 6. 2=1/ 12
1.38/6.2=1/5
4
5.3
0. 52/ 5. 3=1/ 10
1.32/5.3=1/4
5
5.3
0. 68/ 5. 3=1/ 8
1. 14/ 5. 3=1/ 5
6
4.7
0. 43/ 4. 7=1/ 11
0. 97/ 4. 7=1/ 5
7
5.9
0. 34/ 5. 9=1/ 17
1.22/5.9=1/5
Total length of body
Length of oral sucker/
Total length
Diameter of posterior sucker/
Total length
8
6.3
0. 54/ 6. 3=1/ 12
1. 02/ 6. 3=1/ 6
9
6.4
0.52/6.4=1/12
1.42/6.4=1/5
10
6
0.53/6=1/11
1.24/6=1/5
11
6.7
0. 47/ 6. 7=1/ 14
1.52/6.7=1/4
12
6
0.58/6=1/10
1. 53/6=1/4
13
6.6
0. 52/ 6. 6=1/ 13
1.24/6.6=1/5
14
5.8
0.55/5.8=1/11
1.2/5.8=1/5
It will be seen from the above that the ratio of the length of the oral sucker
to the total length of the body varies considerably, i.e., from 1/8 to 117 and that
the one between the diameter of the posterior sucker to the total length also varies,
although within a smaller range. The ratio in the latter case worked out by Fukui
in P. hawkesi is 2/5, which again is far from that existing in the above 14 specimens.
It is therefore suggested that the various ratios worked out by Fukui are not of
TREMATODE PARASITES OF INDIAN ELEPHANT
111
any practical value, dependent as they are bound to be on the degree of contrac-
tion undergone by the worms.
Length .
Breadth .
Thickness .
Position of
genital
pore.
Posterior
sucker.
Ova . .
Pseudodiscus
hawkesi
(My speci-
mens)
3.2—6.7
2—3.7
2—3
Posterior to
intestinal
fork.
1.1—1.59
dia.
0.135×0.07
Pseudodiscus
hawkesi
(Stiles and
Goldberger's
specimens)
3.5—5
2—3
...
Posterior to
intestinal
fork
1.2 dia.
Not seen
Pseudodiscus
hawkesi
(Fukui's
specimens)
10—11
4.4—6
4.5—6
Anterior
intestinal
fork.
4 dia.
0.120 × 0.065
P. macaci
Kobayashi,
1920
11.3
6.5
2
Anterior to
Intestinal
fork.
2
0.12—0.6
P. watsoni
of Stiles and
Goldberger,
1910
8—10
4—5
4
Anterior to
intestinal
fork.
Over 1
0.122—0.130 ×
0.075—0.080
P. watsoni
of Railliet,
Henry and
Joyenx, 1912
5—8
4.2
2.5
At the level
of intestinal
fork.
2.5—2.7
Not seen.
From the table of comparison given above, it will be seen that Fukui's speci-
mens of P. hawkesi compare very favourably in size with P. watsoni of Stiles and
Goldberger, 1910 and P. macaci Kobayashi, 1920. The point regarding the differ-
ence in size between the so-called different species also does not arise. Another
point of difference worthy of note, but which has not struck any other worker, is
the position of the genital pore. Mine as well as Stiles and Goldberger's specimens
of Pseudodiscus hawkesi show it to be present distinctly behind the intestinal
fork, while in P. watsoni of Stiles and Goldberger it is present much anterior to the
intestinal fork. This difference in the position of the genital pore is bridged over
by Railliet, Henry and Joyeux's specimens of P. watsoni. in which case it exists
intermediate between these two extremes, i.e., at the level of the intestinal fork.
Apart from this connecting link its position in Fukui's specimens of P. hawkesi
exactly coincides with the one existing in P. watsoni of Stiles and Goldberger. The
foregoing remarks show that even the position of the genital aperture is not a cons-
tant feature in the specimens under consideration. In conclusion it may be safely
remarked that there exist no valid grounds of differences between the three species,
P. hawkesi, P. macaci and P. watsoni. According to the law of priority, therefore,
the species P. watsoni and P. macaci merge into the synonyomy of P. hawkesi.
Pfenderius papillatus [COBBOLD, 1882].
Only three specimens from an elephent in Assam were available for study. Only
a single specimen was therefore studied in serial sections. It was immature and
112 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I
measured 2.1 in length and 1.83 in breadth. In spite of the fact that the specimen
under study was immature, the cirrus sac was very well developed and measured
0 . 6 in length, 0.27 in breadth and its walls were 0.07 in thickness ; the correspond-
ing measurements in the specimens of Stiles and Goldberger [1910], which measured
4.5—5.5 long, being 0.44, 0.32—0.34 and 0.12 respectively. Fukui [ 1929, 233 ]
remarks that the œsophagus has a thick muscular swelling posteriorly and my
observations also corroborate Fukui's statement.
In my specimens the genital pore was 0.62 from the anterior end. The pos-
terior sucker was 1.27 in diameter and the largest papilla on the ventral sucker
measured 0.08 in length and 0.085 at the base.
Gastrodiscus secundus [Looss, 1907].
About half a dozen specimens found in the fæces of an elephant in Madras were
available for study.
Looss [1907] states that his specimens were obtained by Giles from mules in
Assam remarking at the same time that these worms are found in equines through-
out India. Evans and Rennie [1908] record the presence of these parasites from
horses in Burma. Recently an examination of the specimens obtained from an
elephant in Madras proved on close examination to be Gastrodiscus secundus. In
the Administration Report of the Civil Veterinary Department, Madras, 1930-31,
there appears a mention of a Gastrodisc from an elephant which also is, in all pro-
bability, G. secundus. This appears to be the first record of this parasite from
elephants, but in view of the fact that another worm. P. collinsi, which is a common
parasite of horses, is met; with in elephants also, this finding is not very surprising.
It appears therefore that these two domestic ungulates in India must have some
common habits by which they become similarly infected. Out of six specimens one
was studied in lolo mounts and another in serial section. Although G. secundus
has been quite well described, it is thought desirable to give here the description of
the parasites at my disposal since they come from a different host.
The body of the worm is divided into two portions : the cylindrical or slightly
depressed cephalic portion and the broad, oval, disc-like posterior portion. The
entire body measures 7—8 in length and the greatest breadth is 5—8. The thickness
is 1.75—2. The cephalic portion is 1.87—2.6 broad and 1.09—1.17 long. The disc
is 6.3—6.5 long and 5.8 broad. The mouth is situated at the extremity of the
cephalic portion on the ventral side. It measures 0.33—0.38 in width. At a dis-
tance of nearly 0.4 from the mouth opening are seen numerous tactile papillæ.
These are not, however, " circular or oval thickenings " projecting like small tubercles
as remarked by Looss (1907, 134), but they are papillæ with triangular broad base
TREMATODE PARASITES OF INDIAN ELEPHANT
113
with a slender process projecting from it, the appearance of the entire papilla being
like a pyramid. The abdominal disc has a tendency to roll down its sides ventrally.
The ventral surface of the cephalic portion behind the mouth is slightly excavated
as remarked by Looss. The ventral surface of the disc is covered with " papillæ "
or " pseudo-suckers " bearing on their summits small slit-like openings. As
remarked by Looss " some of these organs are everted, and in this state, represent
small knobs projecting somewhat over their retracted neighbours ". At a distance
of 1.12—1.48 from the anterior end of the disc is seen the genital opening, about
0.42 wide and surrounded by a musculature simulating a genital sucker about 0.79
in diameter. The genital ducts open close together separately on a papilla having a
thickness of about 0.18. The posterior sucker is situated centrally at the posterior
end of the body and measures 1.2—l.7×0.98—1.08.
The mouth is surrounded by an oral sucker measuring 0.32—0.4×0.46—0.65.
It is followed by a portion into which open the two oral diverticula measuring
0.54—0.63 × 0.35— 0.4. The œsophagus is a long straight tube measuring 1.3—1.7
× 0.23—0.25. In specimens in which the cephalic portion is contracted it appears
to be slightly bent at some place. Its walls are glandular. The œsophagus bifur-
cates into two intestinal cæca anterior to the genital opening at a distance of about
0.7 from the anterior end of the disc. The intestinal cæca are straight and pass
along the sides of the body and end at a distance of about 1.49—1.52 from the
posterior end. In some specimens the cæca appear to take a somewhat wavy course.
The testes are situated diagonal to each other in the centre of the body. They
measure 0.98—1.2 × 0.88—0.98. Looss describes the right testis to be anterior,
Evans and Rennie [1908, 17] state that the left one is anterior, Maplestone [1923,
193] remarks that sometimes the left testis is anterior and sometimes the right.
In the specimens I examined, in all the cases, was the anterior testis found to be
on the left side. The coiled vas deferens lies anterior to the left testis and opens
on the genital papilla.
In regard to the position of the ovary there is also a difference of opinion.
According to Looss, it lies on the left side behind the posterior testis ; according
to Evans and Rennie, its position is on the right side. Maplestone, however,
describes it to be present sometimes on the right and sometimes on the left ;
but he remarks that it lies invariably on the same side as the anterior testis.
In the specimens I examined, the ovary was found in all cases to be lying on the
left side, i.e., on the same side as the anterior testis. It measures 0.4—0.48×0.38
—0.43. The uterus takes a sinuous course between the testes and passes on the
right side of the vas deferens to open on the genital papilla quite close to the
opening of the vas deferens. The shell-gland lies on the right side of the ovary and
114 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, I
measures about 0.62 × 0.36. The vitelline glands extend from the level of the
genital pore to the middle of the posterior sucker. The follicles lie mostly on the
outer side of the intestinal cæca, but a few of them are seen overlapping the intes-
tinal cæca as well. They do not, however, occupy ventrally all the space left free
by the other organs as remarked by Looss [1907, 135].
The eggs according to Looss measure 0.15—0.16 × 0.09—0.1 and according
to Evans and Rennie 0.125—0.1625 × 0.0875—0.1. I could not see any ova in
either of the two specimens I studied.
All the specimens are deposited in the helminthological collection of the
Imperial Institute of Veterinary Research, Muktesar.
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*Kabayashi, H. (1915). Watsonius macaci, n. sp., from cæcum of Macacus cynomolgus. Dobuts.
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* This paper was not accessible to me in India.