STUDIES ON THE HAEMOTOLOGY OF DOGS IN HEALTH AND WHEN INJEC-
TED WITH BABESIA GIBSONI (PATTON 1910)
By B. M. PRASAD, Imperial Veterinary Research Institute, Mukteswar
(Received for publication on 14th October 1946)
T HE purpose of the present investigation was to obtain precise data on the total red and white
cell counts, the differential white cell counts and the haemoglobin content of the blood of
dogs in health and when suffering from piroplasmosis due to infection with Babesia gibsoni.
MATERIAL AND METHODS
Three healthy pariah dogs were used. To obtain the normal blood picture, seventeen counts
were made on ten other healthy dogs and the results obtained were more or less in agreement with
those obtained with the three original dogs at different periods prior to infective inoculation. The
dogs were obtained from Almora in the Kumaon hills and their age ranged from two to four years
and body weight from twentyfive to thirty pounds. Two of the three animals were artificially infected
with a laboratory strain of B. gibsoni and the other served as a control. Towards the close of the
experiment this dog, too, was given a dose of infected blood to see if it was susceptible to the disease
and a fatal piroplasmosis resulted. The injections were given subcutaneously with the idea that
the disease might develop as under natural conditions ; the disease is known to be transmitted from
one animal to another by the tick Haemaphysalis bispinosa. The animals were housed together and
kept on an uniform diet consisting of ½ lb. of cooked beef and chapattis given in one meal in the
afternoon ; but during the acute stage of the disease the affected dogs refused solid food and were
then given either milk or soup. The shed was a hundred yards from the laboratory, this distance
was traversed twice daily by the dogs and constituted their daily exercise. When the illness was
advanced, they were unfit to walk, and remained indoors with the control animals. Blood samples
were always drawn at the fixed time of day (10 A.M.)
Both the dogs took the infection and it is interesting to note that while in one, the disease was
fatal in about 16 days after the first appearance of the parasites in the blood, in the other, it was
chronic and the animal apparently recovered.
All samples of blood were collected from the marginal ear-vein or the external Sephana vein,
as between these two sites there was no difference in the blood picture. The area where the puncture
was to be made was cleaned with cotton wool and alcohol, rubbing being continued for about one
minute. When the alcohol had evaporated, a puncture was quickly made with a thin sterilized
hypodermic needle and after rejecting the first two or three drops, the blood was taken up in a capillary
pipette direct from the puncture.
For red cell counts the blood was diluted. 200 times in a potain pipette (0.5—101). The pipette
selected for this purpose gave almost identical counts with the same sample of blood. During the
time the two experimental animals showed signs of severe anaemia, it was necessary, however, to
make the dilution 1 to 100 instead of 1 to 200. Toisson's fluid was used for diluting purposes. A
Thoma (Hawskley) haemocytometer was used and in each case a hundred squares were examined.
Before counting, the white cells were also diluted in potain pipettes at 1 to 11 dilution. It was
essential to use a 4 per cent acetic acid solution as the diluting fluid, since if used in weaker strength
than this, results were unsatisfactory. Thoma (Hawskley), having only one large ruled square
instead of nine as in others, is not very suitable for white cell counts. However its use makes it
necessary to examine at least four-fresh preparations to obtain an average of counts.
Determinations of haemoglobin were made by the Sahli method. Although the advantages
and defects of this have been frequently discussed, the results obtained with it were for practical
purposes satisfactory.
For differential leucocyte counts ordinary clear glass slides were used. For this purpose smears
were prepared from a puncture at the tip of the ear. The hair was cut close and the part sterilized
with 70 per cent alcohol; when this had dried, a piano touch like stroke with a hypodermic needle
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