PROTOZOA IN THE CIRCULATORY SYSTEM 73 



T. cnizi, the trypanosomes appear, after undergoing a 

 series of divisions and form changes, in small trypanosome 

 forms in the rectum of the bug, and are voided in the faeces 

 at the time when the latter feeds on a human host. It is 

 believed that infection in man is established by scratching 

 the site of the insect bite and introducing the organisms 

 into the subcutaneous tissue. 



1. Trypanosoma gamhiense Duttoii 1902 



This trvpanosome is confined to Africa and especially to 

 its equatorial zone. It is the causative organism of the 

 Gambian or Central African sleeping sickness or trypano- 

 somiasis. It is found in the blood, Ivmph, and cerebro- 

 spinal fluid of the human host, and of various domestic and 

 wild animals (reservoir hosts). The flagellate is transmitted 

 by biting flies belonging to Glossina, especially G. palpalis, 

 in the digestive tube of which it undergoes certain de- 

 velopmental changes and in the salivary glands of which 

 the infective metacvclic trvpanosomes become finally 

 lodged for inoculation into a new host individual. The 

 trypanosome occurs in the human bodv as active flagellates 

 only. 



Trypanosoma gamhiense (Fig. 17) is an exceedingly ac- 

 tive flagellate, and is hardly seen in life, although in fresh 

 blood preparation its presence may be seen indirectly by the 

 movement and agitation among ervthrocvtes under a low 

 power objective. In routine detection, stained blood smears 

 (p. 97-100) are used. 



The body is elongate and tapers towards both ends. It 

 is usually sinuous in general outline. There is a nucleus in 

 the approximate center of body. Near the less attenuated 



