524 FAMILY: TRYPANOSOMIDJ^ 



2. Pathogenic Trypanosomes transmitted by Species of Tabanus or 

 Other Blood-Sucking Arthropoda. 



(a) Monomorphic trypanosomes with flagelliim. Kinetoplast well 

 developed. 



T. evansi and many allied forms which are probably races of T. evansi. 



Size: Length 18 to 34 microns (average 24-9 microns); breadth 1-5 to 

 2*5 microns. 



Pathogenicity: Virulent for all laboratory animals. 



(6) Monomorphic trypanosomes with flagellum. Kinetoplast rudi- 

 mentary. 



T. equinum. — Size: Same as T. evansi. 

 Pathogenicity: Virulent for all laboratory animals. 



IL Pathogenic Trypanosomes Secondarily adapted to Direct 

 Passage from Vertebrate to Vertebrate. 



(a) Monomorphic trypanosomes with flagellum. 



T. equiperdum. — Size: Length 16 to 35 microns (average 24 microns); 

 breadth 1-5 to 2-5 microns. 



Pathogenicity: When established, virulent for all laboratory animals, 

 but very difficult to inoculate from horse in the first place. Dog most 

 susceptible. 



According to this scheme, the above trypanosomes can be separated 

 from one another on morphological grounds, with the possible exception of 

 T. equiperdum, which structurally is closely related to T. evansi. 



1. PATHOGENIC TRYPANOSOMES TRANSMITTED BY SPECIES OF 

 GLOSSINA. 



( /) Trypanosomes which Develop in the Stomach, Proboscis, and Salivary Glands of 

 Tsetse Flies. — Polymorphic Trypanosomes 



Trypanosoma gambiense Dutton, 1902.— Synonyms : T . ugandense Ciis.iQ\- 

 lani, 1903; T. castellanii Kruse, 1903; T. hominis Manson, 1903; T.fonlii Maxwell- 

 Adams, 1903; T. gamhice Maxwell-Adams, 1903; Trypanosoon gambiense (Liilie, 1906); 

 Trypanosoma rovumense Beck and Week, 1913; T. tullochii Minchin, 1907; T. nige- 

 riense Macfie, 1913 ; Castellanella gambiense (Chalmers, 1918); C. castellanii 

 (Chalmers, 1918). 



T. gambiense was first seen by Ford in the blood of a man in the Gambia, 

 and was recognized as a trypanosome and named by Dutton (1902). In 

 the following year, Castellani described as T. ugandense a trypanosome 

 he found in the cerebro-spinal fluid of a case of sleeping sickness in Uganda, 

 an observation which was soon confirmed by Bruce and Nabarro (1903). 

 Following these discoveries, it was definitely established that the disease 

 known as sleeping sickness was merely the final stage of human trypano- 



