ABSTRACTS
Control of Stomach Worms in Sheep.—Administration of Drugs in Drinking Water.
(From the Journal of the Council for Scientific and Industrial Research, Commonwealth
of Australia, Vol. 4, No. 1, February 1931).
It has long been hoped that for the treatment of internal parasites, and especially stomach worms
of sheep, some means might be devised which would make it possible to administer the necessary
agent in the drinking water, thus obviating the need for mustering and drenching individual sheep,
as required by existing methods of treatment. In the past, parasitologists have been unable to find
any evidence that drugs given in this way are effective, and it is generally held that a drug in such
dilution that it may be taken in the drinking water daily with impunity must be too weak to exercise
any lethal effect on the parasites. In spite of this pastoralists continue to hope for the development
of such methods of treatment, and there is always a tendency—should any be suggested as giving
beneficial results—for tried and reliable methods to be abandoned, with results which may be serious
to the pastoralist.
During the past year, reports have been received from pastoralists stating that very satisfactory
results have been obtained apparently by the administration in the drinking water of drugs, such as
potassium permanganate, a proprietary preparation containing coal tar acids, &c., and asking that the
employment of these in that manner be investigated by the Council. Since these reports were made
by pastoralists of standing, on whose opinion considerable weight must be placed, the effects of such
drugs given in the manner mentioned have been investigated by the Council's parasitologist,
Dr. Clunies Ross.
Among the drugs tested were potassium permanganate, which was given in 1-5,000 and 1-2,5000
solution, the proprietary coal tar preparation in 1-5,000 solution, copper sulphate (bluestone), in
1-5,000 solution, and a proprietary preparation of sodium hypochlorite in 1-5,000 solution. In
the case of potassium permanganate, the drug was administered to sheep daily for six months in the
drinking water, and, though such sheep were not exposed to re-infection with stomach worms, being
kept throughout the trial in concrete yards, they were still found to contain some specimens of the
large stomach worm on being killed at the end of the trial. Other sheep were given the same drug
daily in the drinking water, and were re-infected experimentally at intervals throughout the trial by
drenching them with young worms. Sheep so treated died in the same time as others not receiving
the drug.
In the case of the other drugs mentioned, sheep were exposed to re-infection while receiving
them daily in the drinking water. In all cases, it was necessary to adopt other medicinal treatment
in order to prevent such sheep dying as a result of the heavy infestation set up, and against which
the drugs appeared to exert no appreciable action.
The use of a 1-4,000 watery suspension of carbon tetrachloride, as prepared by Mr. Finnemore,
of the Pharmacy Department of the University of Sydney, was also investigated, and, while the
drug appeared to exert some action against stomach worms when given daily over a long period,
there was evidence that it had definitely harmful effects on the livers of treated sheep, and that
consequently even though possibly of some effect against the parasites, its use in drinking water
could not be recommended.
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