TRYPANOSOMA CRUZI 87 



to a new vertebrate host. The development in the bug takes about 

 eight days altogether, after which time the bugs are infective. 



There are thus three prin- 

 cipal phases in the develop- s^&s^ i 

 ment of T. cruzi in Triatoma 

 megista : (i) A multiplicative 

 phase (Leishmaiiia-YikQ) in the 



Stomach of the bug, (2) a FIG. 36. Trypanosoma cruzi. Forms found 



... . .. , , , . . . , in the salivary glands of l^iialoma megista. 



crithidial phase, which is also ( After chagas.) 



multiplicative, in the hind-gut, 



and (3) a trypanosome phase, which is " propagative," and apparently 



passes through the wall of the alimentary canal into the body cavity 



and so into the salivary glands. 



Brumpt found that T. cruzi could live in Cimex lectularius^ C. boueti, 

 and Oruithodorus moubata. The Cimex faeces may be infective. 

 Blacklock found multiplication of the parasite in C. lectularius. 



Culture. The trypanosome can be cultivated on Novy-MacNeal's 

 blood agar, and the cultural forms resemble those described in 

 the bug. 



Possible Reservoir. Chagas thinks that probably the armadillo or 

 " tatu " (Dasypus novemciuctus) may be the reservoir of T. cruzi. He 

 also thinks that Triatoma geniculata is a transmitter ; it lives in the 

 burrows of the armadillo. Other carriers may be Triatoma infestans 

 and T. sordida. 



Clinical Features. The trypanosomiasis of Brazil, produced by 

 T. cruzi and spread by Triatoma spp. has received various names, 

 such as oppilagao, canguary, parasitic thyroiditis, and coreotrypanosis. 

 It is also known as the human trypanosomiasis of Brazil, South 

 American trypanosomiasis, and Chagas' disease. 



Chagas 1 reports two principal forms acute and chronic. The 

 acute infection is rare, and is characterized by increase in the volume 

 of the thyroid gland, pyrexia, a sensation of crackling in the skin, 

 enlarged lymphatic glands in the neck, axilla, etc., while the liver and 

 spleen are increased in volume. Sclerosis of the thyroid gland is 

 found at autopsy and fatty degeneration of the liver. During an 

 attack of fever, trypanosomes are found in the blood. The acute 

 form was only observed in children, 



In the chronic form Chagas reports several varieties : (a) A 

 pseudo-myxcedematous form, occurring in most cases, especially up 

 to the age of 15. There is hypertrophy of the thyroid gland or 

 at least signs of hypothyroidism, general hypertrophy of glands, 



1 Brazil Medico, Nov. 15, 1910. Longer account in Mem. hist. Oswaldo Cruz, iii, 

 pp. 219-275. See Sleep. Sick. Bull., Nos. 35 and 40. 



