42 



Where are Trypanosomes found and what is their Import- 

 ance ? 



They are internal parasites in the blood of vertebrates 

 including Man. Many of them are pathogenic, causing 

 disease which is often fatal (e.g., Sleeping sickness in Man, 

 and Nagana or Tsetse-fly disease in cattle and horses). 



They also occur in certain invertebrates which are their 

 alternate hosts. 



How are Trypanosomes transmitted to the Blood of Verte- 

 brates ? 



Those which occur in warm-blooded vertebrates are 

 transmitted by certain species of blood-sucking insects 

 (usually Diptera, or two-winged flies) when these " bite " 

 a healthy individual. In one instance (among horses) 

 they are transmitted during coitus. Those which occur 

 in cold-blooded vertebrates are transmitted in Fishes 

 by Leeches, and in Reptiles probably by Ticks. 



In which Part of the Blood are the Trypanosomes found f 

 In the fluid plasma among the blood corpuscles. 



In what Part of the Body are they found in their Inverte~ 

 brate Hosts ? 



In the food (alimentary) canal. 



How do Trypanosomes reproduce ? 



The general method is asexual by binary longitudinal 

 fission. Multiple division by repeated fission without 

 separation results in rosette-like groups of the parasites. 



Write an Account of Asexual Reproduction in Trypano- 

 somes. 



The ordinary way in asexual reproduction is by binary 

 longitudinal fission (preceded by' division of the two- 

 nuclei) in which both body and flagellum are split equally. 

 In Trypanosoma lewisi (of the Rat), however, this process 



