496 FAMILY: TRYPANOSOMID^ 



Hoffmann (1922) again calls attention to this habit in the case of Rhodnhts 

 prolixus. The larvse were able to continue their development by sucking 

 blood from the recently fed parent bugs or other larvae. The possibility 

 of their becoming infected in this way is evident. 



In Venezuela, Tejera (19196) found naturally infected with T. cruzi, 

 not only R. prolixus, which is the natural vector, but also another reduviid 

 bug, which he informs the writer has been since identified as Erathyrus 

 cuspidatiis. Neiva and Pinto, quoted by Pinto (1923, 1924), have effected 

 transmission by means of R. pictipes. 



It will be seen from the above account that active development of 

 T. cruzi takes place in the mid- and hind-gut of the reduviid bugs, and that 

 crithidia and finally metacyclic trypanosome forms appear in the feeces. 

 Chagas believes that the latter gain access to the salivary glands, and 

 that the bugs produce infection by their bites. In most cases, however, 

 this salivary gland infection does not take place, and as the faeces of the 

 bugs are infective when injected into animals, natural infection may occur 

 by the wound inflicted by the bug becoming contaminated with faeces 

 passed by the bug while feeding or by the faeces being ingested, as in the 

 case of T. lewisi. Brumpt (1913a) and Mayer and Rocha Lima (1914) 

 have shown that mice may be infected by placing infective blood on the 

 buccal mucous membrane, so that oral infection by means of faeces of an 

 infected bug may occur. Brumpt (1912) showed that T. cruzi could 

 penetrate the healthy conjuctiva, and subsequently (1913a) showed that 

 infection could take place through the healthy skin of young mice. 



Reduviid bugs are found naturally infected, not only in the districts 

 in which the human disease is endemic, but also in other localities. Thus, 

 Neiva (1914) in the State of Rio noted that Triatoma vitticejjs, and in the 

 State of San Salvador, T. sanguisuga, T. dimidiata, and R. prolixus, 

 might be infected with Trypanosoma cruzi, while Maggio and Rosenbusch 

 (1915) described the infection of T. infestans in the Argentine. Brumpt 

 and Gomes (1914) have found T. chagasi naturally infected far from human 

 habitations. This seems to suggest that the bug infection is dependent 

 on some other host than man, in whom infection occurs only in certain 

 localities. Pinto (1923) states that Triatoma hrasiliensis has been found 

 infected in various parts of Brazil, and that dogs may be infected with 

 the trypanosomes they harbour. A natural infection with T. cruzi has 

 been demonstrated in the following reduvid bugs: Triatoma megista, 

 T. infestans, T. sordida, T. dimidiata, T. chagasi, T. geniculata, T. viiticeps, 

 T. sanguisuga, R. prolixus, and R. pictipes, though they have not all been 

 incriminated as transmitting the disease to man. 



Reservoir Hosts. — Chagas (1912) noted that T. genicidata harboured 

 a flagellate in its intestine which was indistinguishable from the develop- 



