TRYPANOSOMES. 



By MALCOLM EVAN MACGREGOR, F.R.M.S. 

 (Continued from Page 200.) 



The Effect of Trypanosomes on Man 

 and Animals. 



Both in man and animals the effect that 

 pathogenic trypanosomes have while living in the 

 blood is very similar. We will first consider a case 

 of sleeping-sickness in man. 



Long ago, when Livingstone penetrated into the 

 heart of Africa he noticed that as he got into certain 

 regions of Central Africa the natives spoke of a 

 disease which made people sleepy, and that the 

 invariable result of this sleepiness was death. 



Recognising this and the hopelessness of curing 

 people of the disease when once they had contracted 

 it, the natives were wont to banish the poor unfor- 

 tunate sufferer from his tribe, so that ere long, 

 without anyone to help or look after him, he died 

 of starvation. What brought this disease, or how it 

 wa,s caught, nobody knew ; but while in those days 

 it was more or less confined to comparatively small 

 areas, it has now, since Livingstone's day, spread 

 gradually in Central Africa, and by the name of 

 sleeping-sickness has come to be known as one of 

 the most dreaded diseases of mankind. The 

 trypanosome which causes sleeping sickness is not 

 confined, it is thought, to one species. In the 

 Gambia and other parts of tropical Africa the 

 organism is T. gambiense. In Nyasaland and 

 Rhodesia it appears to be caused by a trypanosome 

 of slightly different form, to which has been given 

 the name T. rhodesiense.* 



The picture of a man suffering from sleeping 

 sickness is a very terrible one (see Figure 226). 

 At first, after he has been bitten by an infected fly, 

 there may be little to notice the matter with him, 

 and the parasites may be in the blood for several 

 months without causing any marked effect — in fact, 

 so long as they remain only in the blood-stream 

 they seem to do little harm. 



But after a time they appear in the cerebro-spinal 

 fluid, and then their deadly work begins. 



The man's temperature goes up, and he feels 

 generally tired, and exhausted by the slightest effort. 

 He becomes hyperaesthetic, so the little everyday 

 knocks that he receives from surrounding objects 

 while he goes about his everyday duties, and to 

 which, while he is well he pays no attention, cause 

 him the intensest pain. There may now be tingling, 

 or even pain, in the soles of the feet and palms of the 

 hands, and peculiar reddish patches may occur on the 

 skin. This continues for a varying period in different 



cases, but finally it gives place to just the reverse con- 

 dition where the patient loses feeling, and gradually 

 becomes stupid, sinking into a heavy lethargy, from 

 which it becomes impossible to raise him. At first 

 this condition is manifest, when one speaks to the 

 sufferer, by his apparent lack of interest in the 

 subject of conversation; he is constantly failing to 

 follow the drift of things, but by raising the voice 

 he is made to grasp what is being said. This con- 

 tinues, and rapidly becomes worse, until in the end 

 a pistol could be fired a few inches from the person's 

 head without his responding at all. There is a dull, 

 sleepy expression about the face ; oedema under the 

 eyes and elsewhere causes the skin to have a puffy 

 look, and the man presents the appearance of a 

 person utterly exhausted from want of sleep. So on 

 it goes, until the patient lies completely comatose, 

 the coma ending in death. 



This is, to some extent, the outward picture of the 

 man, but besides these symptoms he presents an 

 extremely emaciated condition, and general anaemia. 

 There are infiltrations of lymph into the body 

 cavities, the spleen is usually enlarged, and there are 

 changes in the grey matter of the brain and spinal 

 cord ; but on the whole the visible damage to the 

 body is not great. 



Sleeping-sickness in man is a prolonged disease, 

 and may last as long as three years from the time of 

 its onset to the death of the patient. 



In animals, sleeping-sickness produces much the 

 same effect, but its course in the smaller animals, such 

 as the rabbit, the guinea-pig, and the rat, is of much 

 shorter duration, terminating, of course, in the death 

 of the animal. 



The actual condition of " sleep " is perhaps not so 

 manifest as it is in man,. but it is present neverthe- 

 less, and very noticeably in the case of the rat, which 

 places its head between the front paws, rests the 

 crown of the head on the ground, and, throwing the 

 body well forward, looks for all the world as if it 

 were endeavouring to " stand on its head." 



It was at first thought by many tribes of natives 

 in Central Africa that sleeping-sickness was caused 

 by the eating of the m'lolo root (manioc), a root that 

 is eaten fairly extensively. Then came the idea that 

 it was produced by eating a certain species of mud- 

 fish, or that it was caused by " integarti" (the native 

 name for devils). Finally, it was recognised that 

 tsetse-flies had something to do with it, and the 

 tsetse-fly was credited with having a " powerful 

 poison," which it injected while it bit, and that it was 



:,; See Footnote on Page 199. 

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