PROPHYLAXIS IN PROTOZOAL DISEASES 

 TABLE continued. 



239 



With the other diseases prophylactic methods depend 

 on (i) measures to prevent the parasites leaving man 

 or other mammalian hosts, (2) the prevention of the 

 infection of the special alternative hosts in which further 

 development takes place, (3) preventing the access of 

 possibly infective intermediate hosts to susceptible 

 persons, and, where possible (4) rendering such suscep- 

 tible persons immune to- infection or tolerant of the 

 results if they should be infected. 



Parasites can in some cases be destroyed in man, as 

 in malaria by the regular use of quinine, in trypanoso- 

 miasis by use of atoxyl, and in the spirochaetal infections 

 by the use of salvarsan. In these, as well as other cases, 

 protection by the use of mosquito nets or suitable clothing 

 or covering may prevent the parasites being abstracted 

 by mosquitoes or other suitable host ; but these measures 

 should be in addition to the main line of defence, which 

 should be the extermination as far as possible, in any 

 locality, of insect carriers of disease. 



