Abstract
Transmission of the zoonotic tapeworm, Echinococcus multilocularis mainly occurs between the red fox (Vulpes vulpes) and various species of vole. Microtus arvalis is considered one of the key intermediate hosts in Europe. We infected 21 M. arvalis aged 35days (n=2), 56days (n=6), 84days (n=4) and 263days (n=9) with 100 E. multilocularis eggs. Four voles aged 263days were euthanized at 6weeks post inoculation (wpi) with the remainder euthanized 10wpi for analysis of metacestode growth and protoscolex development. Eight C57BL/6j mice (age 35-231days) were included as controls for egg viability (they have been shown to exhibit visible infection after 4wpi) and dissected at 6 (n=2) and 10 (n=6) wpi. M. arvalis had significantly higher metacestode establishment (p=0.008) 6wpi with 27.5±6.63S.D. compared to C57BL/6j with 15.5±0.71S.D. Multivesiculation precluded enumeration at 10wpi in M. arvalis. No protoscolices were found in metacestodes in M. arvalis 6wpi or C57BL/6j at any time point but were found in all infected voles 10wpi (48,056±52,574S.D.). It has been reported that glucocorticoid (GC) profile can affect E. multilocularis establishment. This was assessed by measuring corticosterone in rodent hair to determine if parasite establishment or fertility was related to this stress hormone. No significant differences were found. Data presented here provides, for the first time, a protoscolex development window in this species that has the potential to shed light on the epizootiology of this parasite.
Woolsey, Ian David