TREATMENT OF BOVINE NASAL SCHISTOSOMIASIS
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Obviously, therefore, it is of little use either to give a reacting dose or to increase
the dose progressively at long intervals, as suggested by many of the previous
workers in the treatment of this disease.
Length of the course of treatment.—The length of the course of treatment de-
pends on the number of injections to be given and the interval between them.
The records of previous workers show that the length of the course of treatment
adopted by them varied from four to fourteen weeks. It is seen that they gave
fairly large doses of tartar emetic at long intervals which naturally increased the
length of the course of treatment. It has been pointed out above that the drug
is fairly rapidly eliminated, when given intravenously; hence it would appear
that when the interval between the injections is long, the level of the required
concentration of the drug in the blood is not maintained for a sufficient length
of time to kill the worms. Such animals may appear to have been cured, but
relapses occur sooner or later. This may be one of the reasons why some of
Oxpring's [ 1932 ] animals relapsed after an apparent cure and a second and even
a third course of treatment was found necessary for them, thus extending the
course of treatment over several months. He gave 10 grains of tartar emetic per
dose, irrespective of the body-weight of the animal treated, once in four days,
till ten doses were given to each animal.
Das [ 1929 ] treated some cattle in six villages with intravenous injections
of 10 to 20 grains of tartar emetic. He found that the cases that had five injections
were either cured or improved but those treated with fewer doses did not appear
to have derived any lasting benefit. With the experience gained, he opined
that massive doses may not have curative effect, and said that a sound plan would
be to inject 10 to 12 grains of the drug at less than four days' interval and when
smaller doses are employed, the interval may be reduced to one day. To reduce
the length of the course of treatment or the number of injections, some workers
suggested increased dosage, with a margin of safety, to be given at short intervals
either because the owners fail to present their animals regularly to complete the
full course of treatment or because it is a long and laborious task to do a large
number of injections in one day, if many animals have to be done. Theoretically
speaking, this method may seem to be sound because such doses should kill or
disable the schistosomes shortly after the treatment is begun, thus giving a greater
chance of a cure even if the animal is not subjected to the regular course. But
in practice, the large dose, either progressively increased or otherwise if given
at shorter intervals, may kill the animal itself while under treatment for reasons
already discussed above. Most of the previous workers employed the so-called
reacting or sub-lethal doses and advised the ryots to rest their animals at least
for some time before they worked them. Some employed a routine method of ad-
ministering 10 grains of tartar emetic irrespective of the body-weight of the animal
treated, and even among these, reactions have been observed. Ramaswami
[1933] in a communication to one of us, says that he gave 10 grains of tartar emetic