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PUBLIC RECORD OFFICE
Reference :-
mmimmimC.O.885/25
PUBLIC RECORD OFFICE, LONDON
ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC-
COPYRIGHT PHOTOGRAPH-NOT TO
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the first eight months of the current year, and for several years (if my information is correct) no admissions into the sleeping sickness camp of natives which appear to have contracted the disease recently and locally.
24. It has thus proved quite impossible, by any of the devices at hand, to measure the part played by antelope in transmission of the disease, and, while some danger may lie in this direction, it is much less than was at one time feared.
25. It appears certain, in view of all the circumstances, that epidemic cannot follow recrudescence of disease, whether this is due to existence of natural endemic reservoir, or reintroduction from another region, unless conditions favour its trans- mission from man to man, whether "mechanically "* or otherwise, by Glossina or any other agent.
IV. Repressive versus Exterminative Measures.
26. At Entebbe, and other localities where a population has been left on the lake shore, local clearing measures did not exterminate the tsetse completely. All the main factors for an epidemic-man, fly, trypanosome are or were present, but there were too few flies, and the trypanosome became locally extinct.
27. Complete extermination is thus shown to be unnecessary, and, because- of the considerable extra expense which would be entailed, to be undesirable. All which is necessary, or has been accomplished, is to reduce the chances favouring transmission of the infection from man to man below a certain figure.
28. That which it has been attempted to demonstrate in the preceding pages is that measures designed to reduce the number of bites inflicted by a constant number of flies upon the human host may be much more efficient than measures designed to reduce the number of bites to a comparable extent through reducing the number of flies. The former, therefore, would appear to be the more practicable, provided their application to the requisite extent would not interfere too seriously But there is little question with the ordinary activities of the populations involved. that such measures would interfere very seriously, in this manner, if dependence were to be placed in them exclusively.
29. Exactly the same thing appears to be true of measures designed to the same end through suppression of tsetse. It cannot be done, apparently, without demanding more of the people immediately interested than they are willing to expend.
30. But, as far as can be seen, measures framed upon these respective bases naturally supplement each other,t and in no manner are likely to conflict as far as their combined efficiency is concerned. Therefore the object should be (1) to reduce the prevailing abundance of Glossina (2) with relation to the density of the popu- lation, and (3) with equal regard to the extent to which the population is naturally drawn into contact with the fly, in (4) the simplest, cheapest, and most natural manner possible, and (5) compatible with safety.
31. The all-important question is the extent to which it is necessary to carry such combination measures in order to comply with the final clause.
the
*Conditions preceding the great epidemic on the islands and elsewhere were very favourable to mechanical" tranmission of infection, so much so as to cause a query if this may not have been the principal, and perhaps the only, method as far as man and the human strain of the trypanosome were concerned. At all events" mechanical transmission" is to be guarded against, and has been kept constantly in mind in the course of the studies in testse bionomics leading up to these recommendations.
↑ Surgeon General Gorges, in an address delivered on 9th September, 1915, before the American Health Association, convened at Rochester, N.Y., is accredited in the Press with the following statement relative to the historic zampaigns against yellow fever conducted by him:-
"In Havana and Panama we employed many measures, any one of which probably, if it had been completely carried out, would have succeeded in controlling yellow fever. We know that no one of them, however, could be carried out with complete efficiency. We therefore employed all measures which promised success as extensively as we could." The result, as is well known, was completely to extirpate yellow fever from these localities, and to preclude the likelihood that serious epidemic would ever recur as long as ordinary precau fiona were maintained. There was always the chance that the disease would be reintroduced. however, and it was therefore necessary that precautions should not be relaxed and condition's favourable to epidemio be allowed to recur. The situation in Uganda, as regards the sleeping sickness is not dissimilar in several respecte.
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V.-Conditions under which it is believed that the Lake Shore and Islands might safely be Recolonized.
32. Bukakata is one of the open ports of call for lake steamers, and in the course of the "fly survey of the Buddu coast the district in which it is located was carefully studied. For several reasons the Sleeping Sickness Ordinance has never been very strictly enforced at this point, with the result that the natives have come, or have continued to occupy the lake shore to about the extent of their desire
to do so.
33. Because of soil conditions there are no plantations near the lake. The steamer pier and canoe landing are located on a cleared reach of shore, but within a short distance a fringe of fly-infested bush begins. Infestation is nowhere excessive, but at several points exceeds the average (though only slightly) for the lake shore and islands generally. Fishing is legally permitted only within a few hundred yards of the pier, but actually it is conducted openly along some seven miles of shore, both from the shore and from canoes or rafts.
34. These conditions may be compared with those generally or commonly prevalent in the regions swept by the sleeping sickness epidemic, and before this took place, as follows:-
Conditions now existing at Bukakata.
No huts, villages, or plantations are located within three hundred yards of infested shore.
The natives do not congregate habitually at any point on the shore which is not protected by clearing.
Fishing is not conducted on or within one hundred yards off shore infested to above the average degree.
No regular canoe route passes within one hundred yards off shore which is in- fested to above the average degree.
Conditions commonly prevalent before the Epidemic.
Many villages, fishermen's huts, and plantations were located on or within two hundred or three hundred yards of infested shore.
Most of the canoe landings, water- ing places, markets, etc., were located on infested shore, and very frequently at points densely infested by wandering, food-hunting flies.
Fishing was commonly conducted along densely infested reaches, both on shore and in craft moored within the limits to which flies freely come off shore to a moving object.
The regular routes followed by canoes frequently rounded densely in- fested points from which large numbers of flies may come off to passing craft.
35. The situation was considered carefully, point by point, with respect to the habits of the tsetse, its range inland from the water, the effect of local clear- ings upon its movements along the water front, the chances that men would be bitten while merely passing through densely infeated localities if there were no reason for them to linger etc., etc., and the final conclusion was that the number of "bites" inflicted on a lake shore population living under Bukakata conditions would be at least eighty per cent. less than on a similar population living as was customary before the introduction of infection.
36. If this were a fair estimate it appeared certain that the chances favour- ing transmission of infection from man to man would be reduced by more than ninety per cent., and probably by more than ninety-five per cent.
37. When Trypanosoma gambiense was considered "bionomically," precisely as one might consider the increase and dispersion of Glossina palpalis or any other species of organism, it appeared very doubtful if it would be able to exist as a parasite of man under conditions so little favourable to its transmission from host to host. It was known that it had had some difficulty in holding its own on some of the islands, and elsewhere, under conditions considerably more favourable, and it seemed highly probable that recolonization of the islands and mainland shore under "Bukakata conditions" might safely be undertaken without fear of epidemic, although the recrudescence of the disease in endemic form might follow as a result of infection kept alive in game.
38. This hypothesis has since been confirmed in so many (unexpected) ways that it appears to have been soundly established.
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