488 FAMILY: TRYPANOSOMID^ 



As already remarked, T. cruzi was first discovered in children at Minas 

 in Brazil. Later it was shown to occur in other parts of Brazil also, and 

 by Tejera (1919a) in the States of Zulia and Trujillo in Venezuela, and 

 by Escomel (1919a) in Peru. As will be shown below, the infection in the 

 reduviid bugs is much more widespread in South America than is the 

 disease in human beings which is often termed Chagas' disease. 



Symptomatology. — The disease has been described in detail by Chagas 

 and other observers. It occurs in children of all ages, but assumes 

 an acute form in the first year of life. In these cases the incubation 

 period varies between ten days to a month. There is fever, wasting 

 anaemia, enlargement of the liver, spleen, and lymphatic glands, and 

 especially of the thyroid, producing a puffy condition of the face and body. 

 A more chronic condition exists in older children, in which the above 

 symptoms develop more slowly, while the involvement of the thyroid 

 gland produces a pseudo-myxoedematous or a well-defined myxoedematous 

 condition. The chronic form occurs in children up to fifteen years of age, 

 and is associated with retarded development of mind and body. In any 

 of these cases there may occur special symptoms attributable to involve- 

 ment of the heart, meninges, or brain. The disease, though most com- 

 monly occurring in children, also attacks adults. T. cruzi does not occur 

 in great numbers in the blood of infected individuals. As a rule there 

 is a scanty infection, the parasite being found with difficulty on direct 

 examination. It is more readily demonstrated by inoculation of blood 

 into a susceptible animal like the marmoset or guinea-pig. It has also 

 been found in the cerebro-spinal fluid. The reproducing forms occur in 

 ceils of various organs which are histologically altered by the parasites. 



Pathology. — The pathological changes caused by the trypanosomes 

 consist in the degeneration of the invaded cells, and a leucocyte invasion 

 of the affected tissue in which numerous leishmania and other forms of the 

 parasite occur (Fig. 206). There is an increase of fibrous tissue, often 

 leading to definite sclerosis. This is especially well seen in the thyroid 

 and ovaries. The changes are most marked in those organs most heavily 

 invaded by the parasite, and neither in man nor animals is it possible to 

 predict which part of the body will be most affected. 



Morphology. — The trypanosome itself is a curved, stumpy organism 

 with a sharp posterior end (Fig. 209, 1-3, and Plate V., k, p. 45G). Its 

 length, including the flagellum, varies on either side of 20 microns, but not 

 to any great extent. Some individuals are broad and others narrow, and, 

 as has been suggested in the case of other trypanosomes, this variation 

 was supposed by Chagas to represent a distinction between female and 

 male trypanosomes. The proof of this, however, is lacking. Brumpt 



