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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![Sucli conditions are most often realised around tlie bases of compara- tively clean-stemmed shrubs and trees, and under tangled masses of shrub and creeper overhanjring the crevices among rocks. The requisite shade may be afforded by the shrub or tree itself, or, as must ha];peu, foi* example, in the case of the wild date-palm, by shrub or under-growth surrounding its base. In the case of banana plants additional shade, either from surrounding under-growth or from overhanging trees, would probably always be necessary. Pupae have not been found under clean- stemmed trees where undergrowth is absent. In all probability the larvae are placed close to the stems of trees or shrubs or in the interstices of basal or buttress roots or of rocks in order to guard them from injury and to prevent them from being washed away by rain. It seems possible that they also may be deposited in such earth- filled hollows or crevices in *tree-trunks and branches as exist at no great distance Irom the ground and are not liable to be flooded by rain. This might happen especially where there was not' sufficient bank at the water- side to form a safe deposit and where the other conditions were favourable to the fly’s existence. Apart from such a possibility it is apparently an essential condition for breeding-places that there should be a well-defined upward slope of the ground from the water’s edge, while steep banks or cliffs seem to be exceptionally favourable for pupal deposits. The pupae hitherto found have been placed on scrub-covered banks or shelving ground at a sufficient distance above high water-mark to avoid the probability of their being washed away or destroyed by floods, and also near enough to water-ways to protect them from being, in ordinary seasons, destroyed by bush or forest fires. It is unusual, according to Dr. Bagshawe, to find them more than twenty yards beyond high water-mark. It is unlikely, therefore, that much can be done, under natural con- ditions, towards the destruction of pupae by means of fire; but, by cutting down the scrub along fly-infested banks, allowing it to dry, and then burning it in situ, it is probable that a great many jDupae would be destroyed at the same time that the banks were rendered unsuitable for further deposits.! Dr. Bagshawe is of opinion that natives could, with practice and training, discover pupal deposits fairly easily and thus destroy thenr in large numbers. Unfortunately such a procedure would involve considerable danger to the natives so employed, in any region where Sleeping Sickness is present; but experiments in this direction could be undertaken without danger in our non-infected fly-areas and might lead to most valuable results.! Dr. Bagshawe frequently found pupae deposited in considerable . * Zupitza hns found them in these situations at Diiala in the Cameroons. {Beiheft 2 zum Archiv f. Schiffs- vnd Tropen Eyg. 1908. April, Vol. XII.) I think it probable tliat they would be found in trees in Uganda also at times or places where rainfall is frequent. f This should be tried after the eommencement of the dry season. If it were done in the wet, fresh vegetation would spring up before the scrub was dry enough to bui'ii, and the tly would flourish more than ever. I have seen an instance of this. i Dr. Hodges has lost siglit of the fact that the search is made at dawn and in the late afternoon when the flics do not show themselves and are disinclined to feed. JS’either my natives nor I were ever bitten, to my remembrance.](https://iiif.wellcomecollection.org/image/b2241972x_0018.jp2/full/800%2C/0/default.jpg)
