PUBLIC RECORD OFFICE
ווווווווווווווז
Reference :-
C.O.885
21 PUBLIC RECORD OFFICE, LONDON
ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO
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Could not a communication be sent from the Managing Committee of the Bureau to the Governors of each of the larger Colonies in Tropical Africa, viz., East Africa, Uganda, Nyasaland, Gold Coast, Sierra Leone, Northern Nigeria, Southern Nigeria, pointing out the great advantage that would accrue from an increased knowledge of the tsetse flies and their life history, and suggesting that if a suitable man presented himself he should be allowed to study Glossina palpalis or any other species of tsetse for six or twelve months, if possible the longer period? Difficulties would, of course, arise about the payment of such an investigator. It could perhaps be met by joint contributions from two or more Colonies. Such a man should be a volunteer (keen interest in the subject is essential), and should satisfy the authorities of his ability to do useful work; he must have a bent for natural history, and if he had made a study of some branch of entomology it would be an advantage.
This investigation must not be confused with the mapping of tsetse-fly distribu- tion, a very necessary work which, however, is best done by the combined efforts of all the officials in a Colony. To study the life-history, life conditions, enemies, &c., of tsetse it is necessary to remain at one spot for many months together, and it would be well to set up a breeding plant. The worker would make micro- scopical examinations of the contents of flies, partly with the object of throwing light on their feeding habits and partly to study the micro-organisms which they contain; he could, if facilities were provided, carry on transmission experiments. It would, however, probably be best for him to send pupe which he had bred to a well-equipped institute such as that at Lagos, where the adult flies would be hatched out and used for such experiments. He would test methods of exterminating tsetse, such as Maldonado's fly cloths. He might endeavour to infect the flies with a mould. He would make a detailed study of the fly's enemies, shooting and examin- ing birds, trapping small mammals and examining their stomachs for adult flies and pupa, watching predaceous insects. Even if he made no new discoveries he would amplify our knowledge of the breeding grounds and tell us when and where to remove vegetation and exactly what to remove. Such studies as these, even if anyone has the requisite energy, cannot profitably be made in the intervals of other
work.
In conclusion, I must express my conviction that for the combating of the trypanosome diseases a careful, systematic, and prolonged study of the tsetse flies in the field offers the best chance of success. Such a study has not yet been made.
Sleeping Sickness Bureau, Royal Society, Burlington House, London, W.
February 17th, 1910.
6181
SIR,
No. 7.
A. G. BAGSHAWE.
SLEEPING SICKNESS BUREAU to COLONIAL OFFICE.
(Received 1 March, 1910.)
Sleeping Sickness Bureau, The Royal Society,
Burlington House, London, W.,
February 28th, 1910.
I HAVE the honour to acknowledge the receipt of your letter of February 23rd,* enclosing papers relating to a proposal by Dr. A. May, Principal Medical Officer of North-Eastern and North-Western Rhodesia, that certain districts of North-Eastern Rhodesia which have been closed on account of sleeping sickness should be thrown open for the recruitment of labour for Southern Rhodesia. This is a matter on which decision should be taken only after thorough discussion, to which I propose to subject it. If I criticise Dr. May's proposal it is because my information is fuller
than his.
Dr. May states that his object is to check the further spread of infection, and he believes that the recruiting of natives from these closed areas would have that result, because it would direct the stream of labourers from Belgian territory, where they run risk of infection, to country south of the Zambezi River, where they do not.
* Transmitting the enclosure in No. 5.
He thinks that the risk which natives incur by crossing into Belgian Congo is very great, whereas that of importing sleeping sickness into Southern Rhodesia would, owing to careful medical supervision, probably be less than it is at present, while in the absence of a carrier the chance of its spread would probably be nil. He writes that large numbers of natives are leaving the closed areas and obtaining work in Belgian territory.
Seeing that Dr. May's object is to check the spread of infection, one would like to know the actual risk run by these natives, who presumably go to work in the copper belt. The copper belt has been declared by Yale Massey, Neave, Pearson, and Stohr free from Glossina palpalis, and a glance at the maps drawn up by these gentlemen shows that, if the Luapula river is crossed at a place free from fly or if an adequate clearing is made, it is possible for the Rhodesian native to go to the mines without running any risk of contracting sleeping sickness. If, however, any of these natives are employed in the fly-infested portions of the Luapula and Lufira rivers to the north of the copper belt, they, of course, do run risk of infection.
There remains the more important question of the risk in importing natives from the closed areas of North-Eastern to Southern Rhodesia. That some will be infected is certain, for 65 cases of sleeping sickness have been found amongst them, and, knowing as we do the difficulties in detection where so many natives are concerned, it may be taken as certain that at least an equal number of cases has remained undis- covered. Two questions must here be asked.
(1) Does Glossina palpalis exist south of the Congo-Zambezi water parting;
that is, in the valley of the Zambezi or its tributaries?
(2) Can Glossina morsitans convey the human trypanosome from man to man? (1) Glossina palpalis is not known to occur south of 11° 50' S., but the observa- tions which have been made are insufficient to prove absolutely its non-occurrence. The Zambezi valley is now being examined for this species. It would seem unwise to bring possibly infected natives south till a report has been received from this expedition.
(2) The Secretary, Mr. H. Marshall Hole, cites an experiment by Dr. Kleine in German East Africa, described in the Bulletin of the Sleeping Sickness Bureau (Addendum to No. 11, p. 449), in which 437 Glossina morsitans failed to transmit Trypanosoma gambiense to monkeys. This was a well-devised and important experi- ment, but it cannot be held to settle the matter for all parts of Tropical and South Africa. It was designed to test the possibility of transmission after a period of incubation such as occurs in Glossina palpalis, not of direct transmission by the soiled proboscis of the fly. There are reasons for believing that the conditions of trans- mission are not alike throughout Africa. I would refer you to the unexplained cases of infection south of known palpalis areas which were discussed in Bulletin No. 12 (pp. 491, 492, and 494). I have recently heard of the cases of a German missionary, his wife, and his son, all of whom are believed to have become infected on a journey between their station on high ground at the north end of Lake Nyasa and Chinde, and consequently in country far removed from any known palpalis area. It would be most unwise to ignore such occurrences. It should be noted also that to weed out all cases of trypanosome infection amongst seven thousand natives is, with our present knowledge, impossible.
Having regard to the unexplained infections above mentioned, the difficulty of detecting some cases of human trypanosomiasis, and seeing that the absence of Glossina palpalis from the Zambezi valley is not quite certain, I think that decision on Dr. May's proposal should be postponed. Now that Kleine has put investigators on the right track, every month is bringing us fresh knowledge of the aetiology of the disease, and by the end the year at latest it should be possible to base a decision on the results of a long series of observations and experiments.
In conclusion, I would put it to the Board of Directors, for the proposal is obviously an attractive one from other standpoints than the salvation of the native, whether the occurrence of infection of several Europeans in Southern Rhodesia-and no one can definitely say that such might not occur-would not outweigh the advan- tage to the development of Southern Rhodesia of an accession of even seven to ten thousand native labourers.
I have, &c.,
ARTHUR G. BAGSHAWE,
Director.
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