Echinococcosis in children and adolescents in Bulgaria: a comparative study.

Between 1971 and 1995, 5874 patients underwent surgery in Bulgaria because of cystic echinococcosis caused by Echinococcus granulosus. Of these 5874, 10.6% were children aged < 15 years and 5.25% adolescents aged 15-19 years, giving annual incidences of 1.25 and 2.03/100,000 inhabitants, respectively. Although the annual incidence of surgery for echinococcosis among adults (3.12/100,000) was higher than the combined value for children and adolescents (1.48/100,000), the data indicate that most human infections with E. granulosus occur during childhood and adolescence. In evaluating the epidemiology of echinococcosis or the effectiveness of a control programme, therefore, reductions or increases in the incidence of clinical disease among children and adolescents indicate an improving or worsening situation, respectively. The incidence of surgical treatment for echinococcosis was higher in males than females in all but the youngest subjects (< 5 years) and adults (> 19 years). It was also higher in rural populations than in urban populations, particularly among children and adolescents. Whereas cysts were found more frequently in the lungs of children and adolescents than their livers (51.8% v. 38.3% of the patients), most cysts found in the adults were hepatic (73.5% of patients) and relatively few were in the lungs (14.4% of patients).