Colonial Future
ANTI-TSETSE ALLIANCE
By MICHAEL LANGLEY
THE gnat, Glossina, whose fate was discussed early this month by the International Scientific Committee for Trypanosomiasis
Research, kept its distance from the meetings of that body—a distance of several thousand miles. Its vicious bite, its unmistakable and unapplauding buzz, belong not to a London conference, but to the undergrowth of the tropics. There Glossina, the tsetse fly, feeds on the blood of mammals, leaving behind it a whip-shaped microcosm called trypanosome, a " body-borer," whose effect on human being and animals is to throw them into a lethargic decline.
One way of tackling this menace is to clear the bush and waterside thickets where the tsetse fly breeds. Another way is to eliminate game animals, since these attract the fly—its favourite host is the dog-faced baboon—and increase the risk to domestic livestock. David Bruce, who, at the turn of the century, found that the proboscis of this insect—it is about the size of a house fly—was charged with deadly infection, was the first to recommend these methods. He and Charles Swynnerton, another pioneer, aimed at modifying the conditions in which tsetse diseases flourish. In their day sleeping sickness carried off thousands of Africans, particularly in Uganda and around the central lakes. Their work set the example for projects like the one at Anchau in British West Africa.
The Anchau Rural Development and Settlement Scheme has been described by Dr. T. A. M. Nash, author of Tsetse Flies in British West Africa (H.M. Stationery Office, 1948). A squalid midden of a town was roused from coma, and the fly banished from seven hundred square miles of reclaimed bush in its vicinity. In Tan- ganyika large tracts of infested land are being stripped of the sort of vegetation in which the fly multiplies ; and in Southern Rhodesia three hundred 3,000-acre farms have recently been settled after driving out the wild animals. These methods are not ideal. They sometimes bring the veterinary and medical services into mild conflict with the game and forestry departments ; they are sometimes held up while the local chief entreats the spirits of an insalubrious grove to move to other quarters. Nor is D.D.T. much better ; insecticides kill the desirable together with the undesirable.
The best method of dealing with the tsetse fly is to treat its victims with trypanocidal drugs designed to incapacitate the tiny parasites which it leaves in the blood-stream. The recent meetings, held at the Colonial Office, were concerned with co-ordinating the use of trypanocides over the whole geographical area affected. And, since the development of a great part of this area is the colonial responsibility of Britain, France, Belgium and Portugal, their experts, as well as representatives from South Africa, the Sudan and Southern Rhodesia, were present. Speaking of the latest British contri- bution to the anti-tsetse campaign, the Colonial Secretary told delegates in his opening speech that the formula for antrycide would be placed before them. This name is the trade-mark of a highly powerful tripanocidal drug now in production.
" Antrycide " is an I.C.I. product. It is white and hard to dis- tinguish from unscented talcum powder. The first samples were tested early in 1948, but its process was still a secret when Dr. F. H. S. Curd—he and Dr. D. G. Davey discovered it—died in December last as the result of an accident to the Manchester- Stockport train. Dr. Curd's brief-case, which was taken from the wreckage, contained details for its preparation in two forms- " antrycide sulphate," a soluble powder, and "antrycide chloride," a liquid. By the time of Dr. Curd's death his first experiments, made on rabbits, rats and mice in the Manchester laboratories, had been followed by others under tropical conditions. The effect of antrycide as a cure for tsetse diseases, and as a safeguard against them, had been firmly established, though the duration and degree of immunity obtained from successive doses have still to be confirmed.
Livestock suffering from or exposed to trypanosomiasis are given subcutaneous injections. The sulphate solution is administered for curative purposes, since it is more readily absorbed by the blood- stream, the chloride as a preventive, since its action is a delayed one. It was Dr. Davey who was responsible for proving this. In colla- boration with a Colonial Office committee, he and his technicians have been experimenting for the greater part of a year in the areas worst affected. Their work was not unexciting. Masai lion-hunters were hired to keep injected cattle from being devoured ; in Kenya the intrusions of a rhinoceros drove one of the research staff up a tree. The anti-tsetse campaign in Africa has had its risks, mainly those of disease and accident ; Swynnerton was himself killed in an air-crash in 1938. But these efforts have been well worth while. To a continent where some tribes so value their cattle that they worship them, and where others, at meat-hungry moments, used to resort to cannibalism, the new drug, " antrycide," should come as a godsend. It means that draft animals may be used instead of women's heads for carrying goods and chattels. To the African there is magic here ; to ourselves more satisfaction than is to be gained from homicidal inventions. To the scientist this dicovery is not entirely unexpected.
Scientists and veterinary officers regard antrycide as the latest and most successful of the several prophylactics so far produced for the relief of domestic animals over an area of four and a-half million square miles of Africa. Dimidium bromide has already been proved to give cattle some immunity from trypanosomiasis ; the German drug, antrypol, has been used with effect on camels ; an injection of pentamicline is said to ward off sleeping-sickness in humans for eight or nine months. One of the tasks of the dele- gates to the recent Colonial Office conference has been to investigate the relative merits of these drugs on trypanosomes found in their territories, and of such microcosms there are at least half-a-dozen virulent species. Before their next meeting, to be held under Belgian auspices in June, 195o, it is probable that they will have been able to confirm the claim that antrycide supersedes all other preparations.
The administration of the drug presents no great problems. All colonial Governments have their veterinary laboratories, one of whose functions is to issue selected vaccines for use by the native popula- tion. Experience shows that most African cattle-owners are able to pick up the routine of injecting their animals, and this, I believe,
is true of British East Africa, where there are about fourteen million head of cattle to fifteen million people. So long as antry- cide, of which two tons are to be manufactured this year, for supply, in the first place, to Kenya, Uganda and the Sudan, is applied for
the relief of existing stock, no new agricultural problems may arise. But if the wider implications are to be realised, if the large-scale production of meat for export is to be attempted, a careful survey will be needed, and preferably one whose conclusions are supported by the African experts of the several European colonial Powers.
• Before we can expect beefsteaks in return for the labours of our scientists, new grazing areas will have to be settled and selected strains of cattle established. More important still, the water resources of the British African colonies will need to be further investigated and exploited. Writing of these in a Government report just pub- lished, Professor Frank Debenham points out that livestock cannot live on rainfall averages. Land which is flooded one season may be bone dry at another. Vast regions of this continent are crying out for the services of " hydrological engineers," of men who will teach the African how to conserve supplies, or to locate and tap them at source underground. The reclaimed tsetse zone is not going to add very much to Europe's meat ration until there has been a thorough overhaul of its water-supply.
There are other problems which the removal of the tsetse scourge will raise. The cure for such maladies as rinderpest and East Coast fever may be found in the laboratory, but soil conservation and the improvement of Central African transport are matters requiring close study on the spot. Of these, transport is probably the most vital. It should be approached jointly by all four colonial Powers. That much follows when once it is agreed that colonial meat-production can be expedited by an exchange of ideas and information between West European countries after the manner of those scientists who have been disposing of the tsetse fly. Their committee has been straining at a gnat ; others may be able to look after the camel.
Previous page
