Echotomographic and serological population-based study of hydatidosis in central Tunisia

A population-based echotomographic (ECT) and serological survey of hydatidosis was carried out in a high risk community located in Central Tunisia. 1434 subjects over 5 years of age (93.3% of the population in this age range) underwent an abdominal echotomography (ECT) and a serological test (ELISA with confirmation by counterelectrophoresis). The ECT prevalence rate was 3.5% and increased with age reaching 7.7% in the over 39 years age group. Most subjects (96.0%) had liver cyst(s). The serological prevalence rate was 2.9%. A strong agreement was found between ECT and serological results (Kappa test = 0.449). Taking ECT as a reference, the relative specificity and sensitivity of serology were 99.3 and 62.0 respectively. Most ECT positive seronegative subjects had calcified cysts. These results confirm the presence of highly endemic foci of hydatidosis in Central Tunisia, show a good agreement between serological and ECT results at a population level and demonstrate the high feasibility of ECT as a screening technique.