47 



WoLFEL (K.). Beitrag zur Kenntnis der Tsetse {Glossina morsitans) 

 und der Trypanosomiasis. [A contribution to the knowledge of 

 Tsetse {Glossina morsitans) and trypanosomiasis.] — Zeitschr. f. 

 Infektionskrankh., parasitdre Krankh. u. Hyg. der Hausiiere, 

 Berlin, xvii, no. 1-2, 17th August 1915, pp. 19-36, 1 map. 

 [Received 21st January 1916.] 



In German East Africa trypanosomiasis is the most important 

 disease of cattle next to rinderpest and coast fever. The chief areas, 

 which are shown on a map, are an eastern belt and a western belt, 

 both running from north to south. The eastern one follows the coast, 

 becoming wider and denser towards the south. The western belt 

 reaches^ — with some breaks- — from Lake Victoria to Lake Nyasa, and 

 touches Lake Tanganyika over a considerable distance. Between 

 these belts lie the important cattle breeding districts, viz. : — Arusha- 

 Moshi, parts of Muanza and Tabora, Kondoa-Irangi, Dodoma, Iringa 

 and Langenburg, and to the west of the western belt the still more 

 important areas of Urundi and Ruanda. 



The Tabora district is one of the worst infested and most of the 

 observations recorded here were made there. This area is mostly 

 covered wdth woods or bush, with spaces of steppe and cultivated 

 ground. G. morsitans is present throughout the north-western, western, 

 southern and eastern parts of the district or nearly three-quarters of 

 its area. The only places free from fly are the open steppes and the 

 larger settlements. In the north-east of the district the infested bush 

 merges into bush free from fly, although there is no change of vegetation 

 or soil conditions. It is very probable, however, that infestation will 

 spread into these free areas. Only on two occasions did the author 

 come across places well stocked with game but poor in fly, and only 

 once was fly abundant in a valley poor in game ; in the latter case, 

 the tracks showed that game had abounded there shortly before the 

 place was examined. In the Tabora district in dry years the fly was 

 least abundant at the end of the dry season or at the beginning of the 

 rainy one. The numbers increased at the end of the rainy season 

 and reached their maximum at the beginning of the dry season. 



Experiments in clearing the bush along the roads have given the 

 following results : In rainy weather the fly, when present in moderate 

 numbers in the bush, may be reduced, especially in the morning, 

 by clearing. Where present in abundance, a clearing of 110 yards 

 on either side was not quite sufficient to free the road entirely. In 

 the dry season the fly, when abundant, was reduced on the road, but 

 not to any great extent. Even a clearing of 330 yards on either side 

 of the road was not sufficient to keep it away when very abundant. 

 Clearing is therefore only of value under certain conditions, as, for 

 instance, on roads ruiming through infested river valleys, which are 

 otherwise free from fly. This is the case in the neighbourhood of 

 Kilimandjaro. Where railway stations have to be built in infested 

 places, a clearing of 440 to 550 yards on either side will be effective. 



G. morsitans does not live permanently at high altitudes, the limit 

 lying between 4,200 and 4,600 feet. In hot weather it may be 

 temporarily found above this limit. 



Of 642 flies examined, 3 per cent, contained trypanosomes. Among 

 46 antelopes of eleven species, only three were found to harbour 

 trjrpanosomes, which were also found in one out of thirteen 



