[Estimate of the incidence rates of chronic parasitosis and infections based on the prevalence: Chagas disease in Latin America].

A simple method is described for using prevalence data to estimate the incidence of chronic infections. The incidence rate is estimated as the prevalence rate multiplied by the crude birth rate. The method is applicable to infections which are detectable for life and which have little effect on mortality. Strictly, it is valid only if infection occurs at or shortly after birth, but we show that little error results if infections occur gradually over the first two decades of life. A method of refining the incidence estimate, when age-specific prevalence data are available, is also given. The methods are illustrated using data on Chagas' disease in Latin America.