Echinococcus multilocularis: effect of size of inoculum and route of infection on metastasis, amyloidogenesis and alveolar hydatid cysts mass in mice.

Alveolar hydatid disease (AHD) in mice, caused by Echinococcus multilocularis, is characterized by restrictive and metastasizing progressive growth phases. In experimentally induced infections, neither inoculum size (5, 50 or 250 viable cysts) nor the route (intraperitoneal/subcutaneous) of infection altered the course of disease as measured by the size of the larval cyst mass (LCM) produced. Spleen weight and amyloid deposition were also shown to be independent of the route or size of inoculum. Inoculation of a soluble parasite protein extract (AHC-EXT) induced amyloid deposition, with a dose-dependent threshold. These results support our postulate that soluble component(s) of the LCM are the major factor in the pathogenesis of AHD.