Changing distribution, diversity, and health impact of Echinococcus multilocularis in Europe and North America: Comparison, connections, and opportunities.

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis is a rare but serious animal and human disease in the northern hemisphere. We review published data and reports of E. multilocularis in animals and humans in Europe and North America since 2015. New findings in Europe include the first detection of AE in a wild canid (golden jackal, Canis aureus) and brown hare (Lepus europaeus); evidence for and against the role of domestic and wild felids as definitive hosts of E. multilocularis; new reports in wildlife in 2 countries and human AE in 8 countries; slow range expansion in France, Italy, and Sweden; and increased prevalence in red fox (Vulpes vulpes) in endemic regions of Austria, Italy, and Germany. New findings in North America include rapid range expansion to the west, south, and east (from 5 to 9 of the 13 provinces/territories in Canada, and from 13 to 24 of 50 states in the USA); an unprecedented number of canine and human cases of AE associated with European haplotypes, especially in Alberta, Canada; the first detection of the parasite in a new rodent intermediate host (eastern chipmunk, Tamias striatus); and the first detections in dogs as definitive hosts. Surveillance in wild canids (red fox in Europe, as well as coyotes, Canis latrans, in North America) is key to determining local risk in endemic areas, and to maintain country freedom status in Europe; in addition, recent findings suggest that large-scale screening of livers of horses and pigs may also be useful. From a One Health perspective, control of AE would benefit from voluntary case registries, regulation to prevent introduction of novel strains or hosts into new areas, increased clinical suspicion and access to early diagnoses, broad application of standardized disease staging approaches, standardized molecular classification schemes to enable source attribution and tracing between animals and humans, and increased access to established and novel chemotherapeutic options.