57 



Hornby (H. E.). Tsetse Fly Disease in Domestic and WilcL.^nimajg^e^ 



— Rhodesia Agric. JL, Salisbury, xvl. no. 6, Deceinber~19f9;- ^ 

 493-500, 3 figs. 



The inter-relations of game, tsetse-flies and trypanosomes are dis- 

 cussed. An explanation of the marked decrease in the numbers of 

 Glossitia following upon the great outbreak of rinderpest of the end of 

 last century is quoted. The author quotes the explanation of this 

 phenomenon suggested by Mr. C. F. M. Swynnerton, viz. : — that during 

 the winter months the fly areas contract to those affording sufficient 

 shade, and if during this season the rinderpest killed off the wandering 

 game, not only would the food supply of the flies be greatly diminished 

 but the carriers also would be destroyed [see also R.A.E., B, vii, 10]. 



It is thought that while trypanosomes have adapted themselves to 

 many sorts of blood, their mammalian hosts have also acquired a 

 certain immunity against them ; in fact, there is reason for believing 

 that trypanosomes do not thrive well in the blood of game, but soon 

 die out in it when the game leave the fly-belts. When domesticated 

 animals are attacked they offer no resistance by means of anti-bodies 

 such as the game possess and so are frequently killed outright by the 

 disease. The most they can do as a rule is to retard the progress of 

 the disease to the extent of rendering the condition chronic. The 

 majority of trypanosomes cannot survive in human blood because 

 they have not become adapted to it, but in those parts of Africa where 

 tsetse and man have associated for many decades this has occurred 

 and sleeping sickness has been the result. 



The summary of a recent paper by the author on trypanosomes in 

 domesticated animals is quoted in full {R.A.E., B, vii. 111]. While 

 all domestic animals are susceptible to trypanosomiasis, cattle are 

 naturally immune to T. bnicei and dogs to T. vivax. Local races of 

 animals may develop a high degree of resistance to local strains of 

 the disease ; adult animals are usually the first to succumb. The 

 method of infection and the general nature of the disease are discussed. 



As tsetse-flies do not travel far from undergrowth on a dark night, 

 when moving cattle it is well to choose a cold, rainy night and to keep 

 the cattle in the middle of broad roads. If night travelling is impossible, 

 an open space should be chosen where the cattle can be close herded 

 daring the day-time. Smudge fires around a small grazing ground 

 should be made. If the number of animals is small, a spray of h lb. 

 soap and 2 gals, paraffin to 23 gals, of water should be applied before 

 the belt is entered. Dogs should be carried in fly-proof crates ; horses 

 should be rugged, hooded and bandaged as well as sprayed and they 

 should travel by day with a boy carrying a fly-switch. 



The drugs that have proved most efficacious are orpiment, trypa- 

 rosan and tartar emetic. The dose of the first for an ox is one drachm, 

 given as an electuary. The dose of tryparosan is two drachms, given 

 subcutaneously ; of emetic, one gramme given intravenously. A 

 combination of two or three of these drugs w^U be effective against 

 any but the most severe infections of T. congolense or T. vivax. 

 Disease caused by T. brucei is at present incurable. Routine treatment 

 is being tried of six intravenous injections of 25 c.c. of a 4 per cent, 

 watery solution of tartar emetic at 5 days intervals ; the results will 

 be published later. 



(668) Wt.P18r)0 163. l.aOO. 4.20. B.& F.Ltd. Gp.11'14. A 



