The so called "reversible catalytic model" was applied to the study of certain epidemiological aspects of the human infection by Tripanosoma cruzi. The deterministic model was fitted to prevalence data obtained from populations living in two distinct geographical areas in South America. In spite of the numerous assumptions, which are basic to the model, it was shown that, in general, it describes reasonably well the epidemiologic cynetics of Chagas' infection. The force of infection reflected in 35 effective contacts a year per 1,000 people in a rural area of Venezuela was about three times as large as the force acting upon the population groups living in two small fringe areas of Salvador City, in Brazil. The A. suggests some of the possible further applications of the mathematical model to investigations on the natural history of Chagas' disease.
