Towards global control of cystic and alveolar hydatid diseases.

Control programmes against Echinococcus granulosus in its dog-sheep transmission cycle (Fig. 1) have been successful in many parts of the world'. In contrast, the related E. multilocularis presents a much more complex problem for control authorities. Unlike E. granulosus, the life cycle of E. multilocularis predominantly involves sylvatic hosts (e.g. rodents and foxes) (Fig. 2) and the control of wild life echinococcosis presents a formidable challenge to ecologists and epidemiologists. This review contrasts the two parasites, explaining why E. granulosus in its domestic dog-sheep life cycle has been so responsive to control, and examines the prospects for control of E. multilocularis.