108 TRYPANOSOMES AND SLEEPING SICKNESS 



Probably the deadly Trypanosoma rhodesiense is merely a strain 

 of this wild game trypanosome which has undergone some 

 physiologic change or mutation, making it possible for it to live 

 in the human body. Bruce and some others consider it identical, 

 in every respect except its ability to live in human bodies, with 

 the well-known and widespread T. brucei which causes nagana in 

 wild and domesticated animals. 



A concrete example of sleeping sickness extermination is to be 

 found in the fight against it on the Island of Principe by the 

 Portuguese Sleeping Sickness Commission. Sleeping sickness 

 had been a scourge on the island for years when the Commission 

 began its work in 1911. Its efforts were directed against the 

 tsetse fly, but this was accompanied by an active campaign 

 against pigs, dogs and other trypanosome carriers, and the 

 thorough care and treatment of human victims. The methods 

 used are discussed in Chapter XXVI. The Commission cleared the 

 island of sleeping sickness in a four years' campaign, but the tsetse 

 flies are not yet totally exterminated, and the present condition 

 on the island can only be maintained by constant work in the 

 future, though at comparatively slight cost. 



Chagas' Disease 



A very different but hardly less destructive disease is caused 

 by a trypanosome, Trypanosoma (or Schizotrypanum) cruzi, in 



certain parts of South America. 

 Chagas, of the Oswaldo Cruz 

 Institute, first investigated the 

 disease in the state of Minas 

 Geraes in Brazil. He found that 

 nearly all children in the endemic 



"T* / < regions were stricken with the 



disease, usually before they were 



FIG. 25. Trypanosoma cruzi in blood -, -, ,-p,-, , -,., 



of experimentally infected monkey. one J Q ^ Y Old, I he mortality Was 



A, so-called male form; B, so-called found to be very high, and those 



female form. (After Chagas.) -, . , , , . . , . , 



who survived the initial acute 



attack usually passed over into a chronic diseased condition, very 

 often being left to live a worse than useless life as paralytics, 

 idiots or imbeciles. The disease has since been found in other 

 parts of Brazil and in neighboring countries. Large bloodthirsty 



