298 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, IV

blance to Theileria parasites and this may render the question of diagnosis of
"redwater" by blood smear examination a matter of some difficulty. The round
signet ring forms, however, appear to undergo no such change.

The microscopical method of diagnosis does not readily lend itself for adoption
in the field, since, apart from the fact that it is not every field worker who has
a microscope available for his use, it may happen that smears have been taken
before the parasites have appeared in any large numbers in the circulation, or
again, when they have already disappeared, for they may be present in the blood
only during a relatively short time in the course of an attack, as is witnessed by
the fact that at Muktesar organisms have been found to occur in large numbers
in smears taken on one day but have been completely absent in smears made on
the following day.

2. By the thermal reaction.—A sudden and sharp rise of temperature after the
lapse of a certain period following upon " serum-simultaneous " inoculation against
rinderpest is almost a certain indication of piroplasmosis affection. In uncom-
plicated acute experimental rinderpest, the temperature begins to rise about the
third day after inoculation of the virus and this rise is continued until about the
fifth day when it falls gradually, the normal being reached at about the seventh
day. If, instead of this gradual rise and fall, there is a sudden and sharp elevation
in the temperature after the sixth day, then the fever is almost certainly due to
piroplasmosis. Again, in rinderpest the temperature does not ordinarily rise above
104—105° F., but in acute piroplasmosis it may shoot up to 107° F. or even higher.
Conditions obtaining in the field, however, usually preclude the possibility of all
affected animals being kept under daily observation, and therefore diagnosis by
observation of the temperature reaction cannot be recommended in such cases.

3. By the passing of red-coloured urine.—This does not occur as a characteristic
symptom of the disease in the majority of clinical cases in India, although the
name "redwater", under which the disease is known, owes its origin to this
phenomenon.

4. By the presence of jaundice.—Jaundice is a rare phenomenon in bovine
piroplasmosis and it is believed that in these animals both the kidneys and the
liver function in the elimination of liberated hæmoglobin. On the other hand,
in equine and canine piroplasmosis, diagnosis is chiefly based upon the icteric
condition of the visible mucosæ, as in these animals it is probably only the liver
that is concerned in the elimination process and as such the excess of pigment
gains access to the circulation and the body tissues are thereby stained yellow.

5. By blood counts.—The reduction in the number of red blood-corpuscles
per cubic millimetre of blood may point to piroplasmosis but by itself it can by