animal tkypanoaoimiases in the anglo-kgyptian sudan 53 



Type 3 

 T. jjecoriuii or iiaiiinit (Plate I., figs. 5, 6, and possibly 7) 



Unfortunately, no strain of this trypanosoine has been available in these laboratories 

 in the last year, so the consideration of this type must be a short summary of 

 investigations performed some time ago and a record from work on stained sjjecinieus. 

 This type has been carefully described by Balfour in the Second Report, in discussing 

 trypanosomiasis among the Shilluk cattle. 



Up till recently T. naii.uni has been considered a distinct entity, i.e. a small 

 trypanosoine affecting cattle and possibly mules ; cattle may either die or recover and 

 so far as is known the parasite is conveyed by G. morsitau!'. More extended 

 investigations go to show that 2'. iinmcm affects other animals in the Sudan, or at least 

 that there are types very closely allied to it wliich aii'ect horses, goats and sheep. 



A great deal more work is required to elucidate these types, especially with regard 

 to the susceptibility of laboratory animals. This will be referred to under "animal 

 inoculations and reactions " where the main difficulties of arriving at a conclusion are 

 further entered into. We shall now follow the same system of description as with our first 

 two types, but it must be remembered that we are fully alive to the fact that we may be 

 dealing with the characteristics of possibly more than one variety of trypanosome. 



(((.) [livlruj and unstained. This trypanosome has never been observed in fresh blood Morphologv 

 by the writer but an extract from Balfour's description is here given verbatim. " The 

 trypanosome is a small one. It is not very active in fresh films and I have never seen 

 one traverse the whole field of the microscope. The motion is undulating combined with a 

 vigorous lashing to and fro of the anterior part of the body which tapers to a very tiny 

 fiagellum. Eippling and what may be termed spreading movements have been observed. 

 The parasite advances usually with the narrow end in front but this motion is often Descript 

 reversed. A fact that is very noticeable is that the trypanosome tends to adhere to the ^.^ 



•^ -^ ^ and Bruce 



red blood corpuscles. Even in a thin field this is seen, the parasite seeming to take a compared 

 delight in butting and boring at the erythrocytes. Frequently it gets beneath them and 

 is lost to view, the agitation it jjroduces being the only clue to its presence." This 

 graphic description is exceedingly interesting when compared with Bruce's description of 

 the T. peconiin of Uganda which is also given verbatim. "This trypanosome, when 

 observed in a preparation of fresh blood, is seen to remain at or near the same spot in 

 the field, that is to say it is non-translatory. It is, however, active and restless, the 

 body quivering rapidly, and the undulating membrane and fiagellum keeping up a 

 constant vibratory motion. As a rule it moves with the fiagellum end in front. The 

 contents of the cell are homogeneous, except for a vacuole at the posterior extremity. 



"A marked characteristic of this species is that it exhibits alternating periods of 

 quiescence and activity. When quiescent it is usually invisible as it has a habit of 

 burying itself under small collections of red blood corpuscles." 



One cannot but be struck by the resemblance of these two descriptions, the one of 

 the trypanosoine of the Shilluk cattle and the second that of T. pecomm in the domestic 

 animals of Uganda. 



(b) Fixed and stained 



Lenijtli. Tlie tables of lengths here given are all prepared by Col. Sir David Bruce 

 from slides given him by Dr. Balfour, but do not include the original type strain 

 found in cattle. As there is doubt as to what strain of trypanosome we are dealing 

 with, the provisional nomenclatures, as supplied by Col. Sir David Bruce, are here 

 given above the dift'erent slide measurements. 



ions 



