Annual report of the Sudan Veterinary Service.

  • Sudan. Veterinary Service.
Date:
[1947]
Catalogue details

Licence: Public Domain Mark

Credit: Annual report of the Sudan Veterinary Service. Source: Wellcome Collection.

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    parallels 6°N and 13°N. Parts of the Upper Nile Province have become very severely affected and tens of thousands of cattle have died there. This vast area of over a hundred thousand square miles is unsuited for tsetse flies and none has been found there. It is a hot clayey plain, dry at one season and liable to extensive flooding at another, and its middle is well over a hundred miles from the nearest known tsetse belt. Biting flies, particularly those belong¬ ing to the family Tabanidae and to the genera Stomaxys and Lijperosia are, however, abundant during most of the year, and the close herding of the cattle facilitates mechanical transmission of trypanosomes. 2. A few cases of T. vivax infection have been found there. This species, however, appears to be less pathogenic than T. congolense. Treatment with dimidium bromide (phenanthridinium 1553) Following the successful results of the chemotherapeutic trials of dimidium bromide in 1946 (vide Annual Report 1946) it was decided to arrange a field trial of the drug in 1947. An area was selected in the Southern Sudan, near Malakal, in which a high incidence of trypanosomiasis (about 30 percent) was confirmed by blood examination of representative groups of cattle. All the cattle (both clinically affected and apparently healthy ones) comprising over a thousand in number, were injected intramuscu¬ larly in April with a 2 per cent, solution of dimidium bromide at an approximate dosage of 1 mg. per kilo. The rainy season began shortly afterwards and it became im¬ practicable to carry out any blood examinations during the follow¬ ing four months. The cattle were, however, inspected a few times and the general improvement in the condition of the clinically infected ones, together with the fact that there was not a single report of an infected beast either having died, or having developed symptoms of photosensitisation, was accepted as adequate evidence that the treatment had been successful. The healthy state of the previously infected cattle was in spectacular contrast with that of neighbouring herds where trypanosomiasis continued to take its toll. It would have been better if more critical tests could have been carried cut and more investigation made into the toxicity of the drug. Trypanosomiasis, however, was causing such serious losses in the field that it was decided to embark immediately on large scale treatment on the evidence already available. The plan was to treat all cattle in a particular area in order to include all subclini- cal cases and it was hoped that in this way a trypanosome-free (or virtually free) block of cattle would be formed. Arrangements were made to deal with about a quarter of a million cattle between September and March and by the end of the year 61,783 had been injected.
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