Environmental studies and Echinococcus multilocularis transmission ecology
Résumé
Sustainable transmission of Echinococcus multilocularis (Em) is generally due to a wildlife component and human exposure comes from incidental contact with parasite eggs spread in the environment by carnivore definitive hosts (foxes or dogs having ingested infected small mammal intermediate hosts). The complexity of Em transmission ecology hold in the fact that this parasite adapt to a large range of intermediate rodent and lagomorph host species and that processes underlying transmission are scale dependent, that is can be described by different environmental variables according to the spatial extent and time span considered. Here we present the corresponding nested hierarchy of patterns with the time-space scales at which processes have been described, based on studies carried out in China and Europe. Beyond detecting patterns and understanding transmission processes at each level, one of the forthcoming challenges is to develop methods to upscale and downscale from known levels of the hierarchy in order to predict transmission risk at another higher or lower level that could not be investigated directly