150 TROPICAL MEDICINE AND HYGIENE 



(4) Treatment with atoxyl will greatly reduce the 

 number of trypanosomes present in the blood and thereby 

 diminish the probability of infection of the fly, even in 

 cases where the course of the disease is little affected. 



For the trypanosomiasis of Rhodesia different methods 

 will be required as G. morsitans is more widely distributed 

 and follows game, man, and cattle farther from water. 

 Extermination of the game in broad belts of country may 

 check the spread into districts now believed to be free. 

 An efficient and sufficient resident medical service, with 

 a central laboratory to decide which districts are free, 

 and to supervise the destruction of game and the spread 

 of the disease, would be necessary. 



In South America a chronic febrile disease is due to a 

 blood parasite first described as T. cruzi. A fair number 

 of cases have been observed, and the disease produced is 

 a chronic type of irregular fever associated with a pro- 

 gressive anaemia and enlargement of the spleen, liver, and 

 lymphatic glands. It is most common in children, and 

 death usually occurs from an intercurrent disease, com- 

 monly dysentery or diarrhoea. There is no terminal 

 cerebral stage. 



The parasite, though it resembles the other blood 

 trypanosomes, differs in the method of multiplication. 

 It does not divide longitudinally in the peripheral blood, 

 but in the lungs it divides into eight bodies within a 

 limiting capsule. This method of division led to its 

 being described by Chagas as a Schizoirypanum. 



The carrier is not a biting fly but a blood-sucking 

 hemipterous insect, one of the Reduviidiae, Conorrhinus 

 sanguisuga. After this bug has fed on an infected person 

 it is not infective for eight days or more, but after that, for 

 an indefinite period, it is capable of infecting man or other 

 susceptible animals. 



