Morphology of Various Strains of the Trypanosome Causing Disease in Man in Nyasaland—The Wild Game Strain

Abstract

Up to the present time it has usually been considered that almost all the cases of Human trypanosome disease in man in Nyasaland have been confined to a small area. This, the so-called Sleeping-Sickness District, has been described in a former paper, but it may be repeated here that it is the part of the “fly-country” lying along the western shore of Lake Nyasa, between S. lat. 13° 20' and 13° 50', and extending some twenty miles inland. Through the centre of this area a road runs from Domira Bay on the Lake into North-East Rhodesia. This road, until lately, was a principal highway between the coast and Central Africa. Dr. Aylmer May, the Principal Medical Officer of North-East Rhodesia, who lately visited Kasu, informed the Commission that it was along this trade-route that all the North-East Rhodesian, cases of Human trypanosome disease have occurred. It is said that some 25,000 native porters passed along this road every year, and as they entered a Glossina palpalis area at the Congo end of their journey, it seemed at first natural to suspect that the disease was true Sleeping Sickness, and had spread from west to east along this trade-route. This suspicion was shown to be groundless by the discovery that the parasite causing the disease in North-East Rhodesia and Nyasaland is not Trypanosoma gambiense , but a distinct and separate species giving rise to a totally different disease. The question then arose as to whether this was an imported or indigenous disease. It has, therefore, been one of the objects of this Commission to determine whether the trypanosome causing Human trypanosome disease in Nyasaland is restricted to the game and “fly” of the Proclaimed Area, or if it extends to the north and south along the “fly-belt.” If it is found to extend over all the “fly-area” in Nyasaland, then the disease is probably native to the soil and not an importation from Tanganyika or the Congo. But it will be well at this point to lay down definitely the various opinions or theories at issue. These are three in number.