Observations relating to the transmission of sleeping sickness in Uganda, the distribution and bionomics of Glossina palpalis, and to clearing measures / by Aubrey D.P. Hodges.
- Hodges, Aubrey Dallas Percival, 1861-1946.
- Date:
- 1909
Licence: In copyright
Credit: Observations relating to the transmission of sleeping sickness in Uganda, the distribution and bionomics of Glossina palpalis, and to clearing measures / by Aubrey D.P. Hodges. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![tlie ily’s migration, from the lake or river into wliicli they ilovv. It would he advisable ihat, in future investigations, tlie course of such a stream should bo followed to its mouth, in order to ascertain the existing condi- tions. It is not always possil)le to predicate with certainty the presence or absence of fly on the banks of a running stream from its physical characteristics at one S]iot. The conditions obtaining between this point and the lake or river it feeds must also be known. The feeding-range is increased in *dull, still weather and where tliere are wide belts of scrub or forest at the waterside. It is also certain that the existence of constant and extensive human or animal traffic, and especially the former, across fly-areas or to and fro between them, is the most potent factor in influencing local migration and distribution and also in extending the feeding-range under conditions favourable to the fly. The facilities for migration, as well as the feeding-range, are doubtless on the whole increased in the wet season by the increase in the size and number of watercourses and by the increase of shade-vegetation along their banks, and perhaps also by the movements of sudd during floods. But it is quite possible that in certain cases the conditions may be more favour- able to the presence of fly in the dry season than in the wet. For example, what is a narrow stream with steep or scrub-shaded banks in the dry season may become during the rains a wide sheet of water or swamp with unshaded banks, in which case the fly would migrate up or down stream to more favourable haunts, to return with the fall of the flood. It may be useful at the present stage to give a brief survey of the general distribution of 0. pcdpalis over the Uganda Protectorate as a whole. This would be represented on a map, with the nearest approach to accuracy, by a thin, more or less interrupted, line drawn along the shores of the great lakes and the islands contained in them, along the banks of the river Nile and for a few miles up-stream from the moutlis of most of those rivers which flow into the Nile below Foweira, into Lake Albert or into Lake Albert Edward. It is absent from the great rivers entering Lake Victoria and from must of the small streams except in Usoga. It is very plentilul along the northern shores of Lake Victoria but decreases in abundance and continuity of distribution on the western shore towards the south. It is very abundant in the Sesse Islands and on part of the mainland opposite them. South of this it is much less plentiful, and apparently does not occur south of Duma, some twenty miles from the Anglo-German boundary. It is found in abundance along the banks of the Victoria Nile as far nortli as Kibuye, a short distance from Lake Kioga. It exists in patches ' on }>arts of the Mpologoma Liver and some of its tributaries, but has not -j been observed on Lake Kioga itself. Below this it is found again on the ; Victoria Nile near Mruli and the mouth of the Kafu Liver. Between j Mruli and Foweii’a it is found in comparatively few places, but occurs on j both banks. From Foweira to Lake Albert it is again very abundant ^ on the Nile banks and is also present on the tributary streams. Along the Eastern shore of Lake Albert tlie fly is plentiful north of Butiaba and occurs on jiractically all the rivers and streams as iar as, and sometimes even beyond, the e.scarpment, which, in the neighbourhooil * My experience was perhaps exceptional; in dull weather, 1 saw few Hies and those were sluggish and disinclined to bite. When, in the course of flight experiments, it was necessary for me to catch largo numbers of Hies I looked upon a dull day as one lost. J* Wide belts of scrub reaching the water side greatly iacreaso the feeding range.](https://iiif.wellcomecollection.org/image/b2241972x_0008.jp2/full/800%2C/0/default.jpg)
