Echinococcus granulosus (Cestoda: Taeniidae) infections and moose – wolf population dynamics in southwestern Quebec

The prevalence, mean number, and mean total weight of Echinococcus granulosus cysts in the lungs of moose increased with moose density in southwestern Quebec. Such responses in the level of infection were documented in areas of 0.17, 0.23, and 0.37 moose/km 2 . The increase of E. granulosus infection in moose was attributed to higher densities of wolves, the definitive host of this parasite, as well as an accompanying increase in the rate of wolf predation upon moose. The aggregated distribution of this parasite within the moose population is considered to reflect the highly heterogeneous use of space by wolves and the consequent aggregated distribution of parasite eggs within the environment. A possible regulatory effect of E. granulosus infections on moose numbers is discussed.