Echinococcus multilocularis transmission predominantly occurs in Europe between the red fox (Vulpes vulpes) and various species of rodent intermediate hosts. We infected 3 species of rodent, Myodes glareolus (n = 47), Mesocricetus auratus (n = 11) and outbred Mus musculus (CD-1 IGS) (n = 9) with an E. multilocularis egg suspension that contained 100 eggs with viable oncospheres and performed post mortem examination 6, 8 (M. glareolus) and 10 weeks post inoculation (wpi). C57BL/6j mice (n = 4) were used as positive controls as they have been shown to exhibit macroscopic liver lesions 4 wpi. To the best of our knowledge, this is the first study to experimentally assess susceptibility in the ostensibly competent host M. glareolus. Lesions were only detected in 2 of 47 M. glareolus (4.3%) at 8 and 10 wpi and although both contained protoscolices (1675 at 8 wpi and 88 at 12 wpi) the low percentage of infected animals brings into question their role as transmitters of the parasite. Significant differences were observed between inbred and outbred mice with E. multilocularis infection in the former demonstrating increased establishment (p ≤ 0.0001) and growth (p ≤ 0.0001). No lesions were found in all 11 M. auratus.
Keywords: Echinococcus multilocularis; Intermediate hosts; Metacestode.