Human echinococcosis in Bulgaria: a comparative epidemiological analysis

The present article describes the importance of human echinococcosis as a p ublic health problem in Bulgaria, outlines the control measures carried out and evaluates comparatively the situation over three periods spanning 46 y ears (1950-1995). During the first period (1950-62), a total of 6469 new su rgically confirmed cases of hydatid disease were recorded in Bulgaria, with an annual incidence of 6.5 per 100 000 population, and the infestation rat e in domestic animals and dogs was high. Echinococcosis was endemic through out the country. The organization of a control campaign, initiated in 1960, led to a considerable improvement in the situation during the second perio d (1971-82). Morbidity among humans gradually decreased, with an average in cidence of 2.0 per 100 000, and the proportion of infected animals also fel l. The distribution of echinococcosis was characterized as sporadic or of l ow endemicity. During the third period (1983-95), owing to administrative i rregularities and economic changes, funds for supporting the campaign were reduced and control structures were dismantled. As a result, the incidence rose to 3.3 per 100 000. Echinococcosis again became endemic, in some regio ns hyperendemic. The findings provide convincing evidence that cessation of control measures or reduction of campaign activity can lead to intensifica tion in the transmission of Echinococcus granulosus and to a resurgence in echinococcosis to previous levels.