A systematic review and meta-analysis on anthelmintic control programs for Echinococcus multilocularis in wild and domestic carnivores

Human alveolar echinococcosis (AE), caused by the tapeworm Echinococcus multilocularis, is one of the most dangerous zoonoses in the Northern hemisphere. In Europe, the parasite's life cycle is sylvatic, involving small rodents as intermediate hosts and red foxes as the major definitive hosts. Given the severity of this disease in humans and the high levels of environmental contamination with E. multilocularis in endemic areas, it seems crucial to implement control measures in order to prevent human AE. This systematic review identifies previous anthelmintic control programs targeting E. multilocularis in wild and domestic carnivores and evaluates the effectiveness of the different strategies implemented. A search through six databases identified 302 scientific papers for the period 1950–2015, of which only 17 were retained according to the inclusion criteria set. These 17 papers focused on control of E. multilocularis by baiting foxes in highly endemic areas of Europe or Japan, with the exception of one study focused on dogs in Alaska. The papers highlighted differences in baiting types, baiting frequency, choice of control areas and length of treatment period. Overall, these studies resulted in a sharp and statistically significant decrease in parasite prevalence, confirmed by the absence of overlap between confidence intervals for the pooled risk differences of control and treated areas. A monthly baiting frequency was proven to be highly effective at decreasing E. multilocularis prevalence in foxes, even in highly endemic areas and in a short period of time. Nevertheless, when foxes were not fully dewormed, the parasite showed a strong capacity to rapidly recover its initial prevalence. The fox baiting approach appears to be the most useful method for controlling the sylvatic life cycle of E. multilocularis, but it require a cost/benefit analysis before it is likely to be accepted by stakeholders.