Echotomographic evidence for a highly endemic focus of hydatidosis in central Tunisia.

now screening a rural community identified as at high risk, with a surgical incidence rate for hydatid cyst of 200 per 100 000 inhabitants (mean for central Tunisia 22 per 100 0002). In this community, 1179 subjects over the age of 5 years (83-8% of the population in this age range) were examined by echotomography with a portable apparatus.1 41 hepatic cysts and 1 splenic cyst (prevalence 3-6%) were diagnosed. In the study population 17 subjects (including 1 with a positive echotomogram) had previously been operated on for abdominal hydatid cyst (cumulative prevalence rate 4-9%. Given the agreement between ELISA findings and echotomographyl,3 and the fact that echotomography is more feasible than ELISA, we agree with Macpherson et al that echotomography be used alone for assessing the prevalence of hydatid cyst. Our two surveys in neighbouring communities in central Tunisia have yielded very different prevalence rates and have uncovered a focus of unexpectedly high endemicity. In such an