APPENDIX E. 



TRYPANOSOMIASIS— LEISHMANIASIS— 

 PIROPLASMOSIS. 



The Pathogenic Trypanosomas. 



The trypan osomata are protozoal organisms belonging to the 

 sub-class Flagellata, and many members of the genus have come 

 to be recognised as living in the blood and tissues in various 

 animals, and as causing important disease conditions. As long 

 ago as 1878 the Trypanosoma lewisi was observed infesting the 

 blood of rats, and it has been found to be sometimes capable of 

 causing death. Other diseases in which similar organisms have 

 been found are Surra, which occurs in cattle, horses, and camels 

 in India, and which is associated with the Tr. evansi • Dourine, 

 a condition affecting horses in especially the Mediterranean 

 littoral (Tr. equiperdum or rougeti) ; Mai de Caderas, a disease 

 of South American horses (Tr. equinum or elmassiani) ; Tse-tse 

 Fly Disease or Nagana, affecting horses and herbivora in South 

 Africa (Tr. brucei) ; trypanosomiasis of African cattle (Tr. 

 theileri) ; and — most important from the human standpoint — 

 the trypanosomiasis and sleeping sickness of West and Central 

 Africa associated with the Tr. gambiense and Tr. ugandense, 

 which are now believed to be the same organism. These 

 diseases present many general resemblances to one another. 

 They tend to be characterised by wasting, cachexia, anaemia," 

 fever often of an intermittent type and irregular cedemas, 1 and 

 frequently have a fatal result. In many cases the infective 

 agent has been proved to be conveyed from a diseased to a 

 healthy animal by the agency of blood-sucking insects. 



Morphology and Biology of the Trypanosomata. — If a drop 

 of blood containing trypanosomes be examined, the organism 

 will be seen to be a fusiform mass of protoplasm which at one 

 end passes into a pointed flagellum. In the living condition the 

 trypanosome is usually actively motile by an undulatory move- 



