title: Stability of the southern European border ofEchinococcus multilocularisin the Alps: evidence thatMicrotus arvalisis a limiting factor.
abstract: The known range of the zoonotic fox tapewormEchinococcus multilocularishas expanded since the 1990s, and today this parasite is recorded in higher abundances throughout large parts of Europe. This phenomenon is mostly attributed to the increasing European fox populations and their invasion of urban habitats. However, these factors alone are insufficient to explain the heterogeneous distribution of the parasite in Europe. Here, we analysed the spatial interrelationship ofE. multiloculariswith the known distribution of seven vole species in Ticino, southern Switzerland. Among 404 necropsied foxes (1990-2006) and 79 fox faecal samples (2010-2012),E. multiloculariswas consistently found in the north of the investigated area. No expansion of this endemic focus was recorded during the 22 years of the study period. This stable endemic focus is coincident with the known distribution of the vole speciesMicrotus arvalisbut not, or only partly, with the distribution of the other autochthonous vole species. Our results give evidence that this vole species plays a crucial role in the maintenance of the parasite's life cycle and that its absence could be a limiting factor for the spread ofE. multilocularisin this region.
authors.affiliation: Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland.
authors.forename: Diogo
authors.initials: D
authors.lastname: Guerra
authors.affiliation: Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hegglin
authors.affiliation: Cantonal Veterinary Office, Via Dogana 16, CH-6500 Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Bacciarini
authors.affiliation: Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland.
authors.forename: Manuela
authors.initials: M
authors.lastname: Schnyder
authors.affiliation: Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Deplazes
keywords: Echinococcus multilocularis; Microtus arvalis; Switzerland; distribution; fox; rodents