COURSE OF CHAGAS' DISEASE 113 



or else others of the trypanosomes observed in species of Triatoma 

 from Argentina to Central America may not be identical with 

 the trypanosome which is the cause of Chagas' disease. 



The Disease. — In endemic regions Chagas' disease is so 

 prevalent that children are usually attacked within a few months 

 after birth, and at this tender age are often unable to withstand 

 its effects. If death does not result the disease passes over into 

 one or other of its various chronic forms. As a result it is very 

 rare to find acute cases in anyone but young children or new 

 arrivals. The latter, however, usually come from other infected 

 regions and show marks of the chronic disease, and so are not 

 susceptible to a new acute infection. 



The acute infection is marked by a constant high fever, lasting 

 from ten to thirty days, often without remission, and by a charac- 

 teristic swollen face, noticeable from a considerable distance. 

 The skin has a peculiar feeling of " crepitation " due to the 

 mucous infiltration of the tissue under the skin. The lymph 

 glands especially in the neck and arm pits swell up, the liver and 

 spleen become enlarged, and the thyroid gland becomes swollen 

 as in goitre. In fact, most of the symptoms are connected with 

 interference with the thyroid gland which, while becoming 

 massive in size, becomes reduced in function, thereby causing a 

 number of nervous and constitutional symptoms. This inter- 

 ference is due, apparently, not so much to invasion by the para- 

 sites as to a specific effect of the toxins produced by them and 

 carried by the blood. These are the constant features of the 

 disease; the other symptoms vary according to the localization 

 of the parasites. Frequently they multiply in the heart muscles, 

 and the functions of the heart may be seriously interfered with. 

 Very often, and with the most dire results, the parasites invade 

 the brain and spinal cord. When this happens the mortahty is 

 high, and it is only a pity that it is not higher, since it would 

 be better if death always eliminated these unfortunate trypano- 

 some victims who are spared only for an unproductive, piteously 

 mutilated life, doomed to grow up with the intellect of an infant, 

 or as paralytics, idiots or imbeciles. 



The chronic forms of the disease follow the acute form by the 

 development of a substance in the blood which is deadly to the 

 trypanosomes, so that the latter are restricted to the protecting 

 tissue cells in which they multiply. The commonest chronic 



