NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
360 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND. ANIMAL HUSBANDRY [ III, IV.
outer edge of the cloth-cover. This worked well for a while until in one instance
a proportion of the ticks got pressed to death, apparently as a result of the dog
having reclined on the side of its body on which the ticks had been placed (for the
most convenient site for placing the ticks on the host's body was found to be the
sides). This difficulty was overcome by the simple expedient, of fixing a small cup,
by means of Chatterton's Compound, over the cloth-cover, a suitable cup for this
purpose being the lid of a " Craven A " cigarette tin (the dimensions of the cloth-
cover itself not exceeding 1¼ N square). Before fixing, the lid is perforated by a
number of holes to admit of air, and a piece of muslin is gummed on to the inside
of the lid in order to prevent the escape of any ticks through the boles, in the event
of the cloth-cover getting accidentally detached at some point along its margin.
To prevent the cup from dropping off as a result of hitting against a projecting
object, the animal is made to wear a tight-fitting dog-coat, broad enough to enclose
the entire circumference of the middle of the body and maintained in position by
looping it over the tail and buttoning it on the sides and in front below the neck
(Plate XXXIV, Fig. 1). Broad (cited by Williams, 1904) recommends sprinkling
bandages with cayenne pepper in order to prevent dogs from biting them off, but
the use of the carton collar, as mentioned above, would appear more simply to meet
this purpose, whilst by lightly tying together the hind legs, the dog is effectively
prevented from making use of them in scratching off the cloth-cover. During the
summer months at Muktesar, the periods taken by the different stages of R.
sanguineus to complete their feed have been found to range from about 4 to 9 days,
and in the feeding experiments described below, the cloth-covers were opened with
due regard to these periods, whilst the ticks themselves were collected by brushing
them off the body of their hosts into a funnel attached to a large entomological
tube closed at the bottom.
The effectiveness of the feeding method described above is illustrated in Fig. 2,
Plate XXXIV, which shows a group of engorged ticks confined to a circumscribed
area on the host's body.
THE TRANSMISSION EXPERIMENTS.
The ticks used in the present experiments had all been bred out from eggs
deposited in captivity and had their infective feed in the larval stage on dogs show-
ing definite symptoms of P. gibsoni infection, as evidenced by anæmic changes
and the occurrence of parasites in the circulating blood, although the occurrence of
febrile symptoms was not found to be a constant feature of the infection. In the
PLATE XXXIV.
FIG. 1. Dog with collar and coat on and with hind legs lightly tied. The area
where the ticks have been placed is indicated by arrow.
FIG. 2. Portion of body of dog showing engorged ticks in situ (with the cup and
cloth-cover partially removed).
VECTOR OF CANINE PIROPLASMOSIS DUE TO P. GIBSONI
361
present experiments, only two dogs provided the infective feed to the larval ticks,
as shown in the following Table :—
Ticks
Lot A .
„ B .
„ C .
„ D .
„ E
„ F .
Dog
No.
239
239
239
240
240
240
Number of
larvæ
used
200-300 .
About 100
500-600 .
200-300 .
500-600 .
About 300
Number
of larvæ
recovered
All .
All .
All .
All .
About 100*
All† .
Duration
of larval
feed
4 days .
5 „ .
6 „ .
5 „ .
4 „ .
6 „ .
Average body
temperature and
condition of blood
of host during
larval feed
102.3°F. . A
few
P. gibsoni. Anæmia.
102°F.
Rare
P. gibsoni. Marked
anæmia.
102°F.
A
few
P. gibsoni. Marked
anæmia.
102.9 o F. Very rare
P. gibsoni.
Slight
anæmia.
101.5°F. Fairly fre-
quent
to
rare
P. gibsoni. Marked
anæmia.
101.7°F. A few to
rare P.
gibsoni.
Marked anæmia.
Remarks
*Cloth-cover
found detached,
apparently due
to
insufficient
adhesive.
†Only about 20
larvæ
found
alive;
others
had fed, but
were
found
dead, presum-
ably owing to
an extension of
adhesive
to
centre of cloth-
cover.
The temperature shown in each case in the foregoing table represents the
average of the readings taken both in the morning and in the evening during the
full period of the infective feed of the ticks and has been inserted in the table
merely with the object of completing the protocols of the dogs concerned, for, as
already mentioned, the occurrence of febrile symptoms was not found to be a
certain indication of the development of the infection, so that no animal was
regarded as definitely infected until the appearance of a fair number of parasites
in the circulation, associated with varying degrees of anæmic changes, and as will
be seen from the table the larvæ were infected from such dogs as showed these two
symptoms of the disease, except in the case of lots B and D, which, in the absence
E 2
362 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, IV.
of a more suitable subject at the time, had to be fed upon dogs showing only
" rare " or " very rare " parasites.
As has been mentioned earlier in this note, the infectivity of the nymphs and
adults derived from one or more of the six lots of larvae was tested upon five dogs.
The results of these tests are summarized in the following Table :—
Dog
No.
194
236
248
34
29
Number of ticks
used
300-400 nymphs
derived from
Lot C.
About
200
nymphs derived
from Lot C
About
100
nymphs derived
from lots fed
on both Dog
No. 239 and
Dog No. 240.
About
100
adults derived
from
mixed
lots as above.
About 90 adults
derived from
mixed lots as
above.
Number
of
ticks
recover-
ed
*About
100.
All .
All .
All .
74
Duration
of
feed
6 days
6 „
6 „
8 „
10 „
Number
of days
dog kept
under
observation
56 days
73 „
89 „
31 „
11 „
Result
+
+
+
..
..
Incuba-
tion
period
29 days
30 „
28 „
..
..
Number
of days
parasites
seen in
blood
9 days
24 „
18 „
..
..
Remarks
*Collar found
damaged
and cloth¬
cover sli-
ghtly dis-
lodged.
Dog discon-
tinued.
Dog discon-
tinued.
Dog discon-
tinued.
Died of sus-
pected dis-
temper.
Died of pneu-
monia.
The incubation period shown in the foregoing table against each of the three
dogs that developed the infection represents the interval between the date on which
the ticks were placed upon the host and the first appearance of the parasites in
the circulating blood. It is noteworthy that this period was more or less constant
in the three animals, for this is a strong confirmatory evidence that the animals
actually developed the infection as a result of being bitten by the ticks and pre-
cludes the possibility of natural infection or resuscitation of dormant parasites.
It has already been remarked that an elevation in body temperature has not
been found to be a reliable indication of the development of artificial P. gibsoni
nsmission of Canine Piroplasmosis by Rhipicephalus Sanguineus'
CHARTS OF DOGS NO. 248, No. 236 AND NO. 194.
Fig. I .—Transmission of Canine Piroplasmosis by Rhipicephalus Sanguineus.
CHARTS OF DOGS NO. 248, No. 236 AND NO. 194.
VECTOR OF CANINE PIROPLASMOSIS DUE TO P.
GIBSONI
363
infection in dogs. This is illustrated by the temperature charts (Fig. 1) for,
as will be seen from these charts, in none of the three animals did a rise
in temperature bear any definite relationship to the appearance of the para-
sites in the circulating blood. It will, however, be noticed that two of the dogs
showed Babesia canis, whilst the third showed rare Hepatozoon canis in the blood,
and it is not improbable that the supervention of these concurrent infections
determined to some extent the temperature reaction developed by these animals.
It is hoped that it will be possible to obtain definite information on this point when
the experiments are repeated on " clean" dogs housed in tick-proof kennels.
Arrangements are in progress to undertake these experiments as soon as possible.
REFERENCES.
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Government of India. No. 29.
Müller, G. and Glass, A. (1926). Diseases of the Dog and their Treatment. Alexander Eger.,
Chicago.
Nieschulz, O. and Wawo-Roentoe, F. K. (1930). Uber die von Zecken. Zentralbl. f, Bakt.
Abt. orig., 115, 486-488.
Nuttall, George H. F. (1913-14). Observations on the Biology of Ixodidae. Part I. Parasi-
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Patton, W. S. and Cragg, F. W. (1913). A Textbook of Medical Entomology. Christian Litera-
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