Epidemiological Aspects of the Planning and Evaluation of Hydatid Disease Control*

SUMMARY: Reasons are given for more adequate epidemiological studies than are customary preparatory to and following the institution of disease control programs. Using as examples the experiences of different countries with hydatid disease, attention is given to the value of the analysis of these types of data for identifying determinants of initially high or low prevalences of disease, for rationally planning pilot control trials and for identifying reasons for differences in rates of control progress and needed changes in control strategies.