TABLE 7.

Variable factors in the epidemiology of E. multilocularis

Key factors	Selected contributing factors (defined or suspected)
Definitive hosts and the adult parasite	Animal species: geographic and spatial distribution, population size and dynamics, interactions with prey animals, feeding habits, behavior, landscape characters of the habitat, relation to human habitats
	E. multilocularis: prevalence, intensity, and duration of the infection; intensity of egg production and release; host immunity
Parasite eggs in the environment	Dispersal and survival of eggs, conditions of climate and weather
Intermediate hosts and the metacestode stage	Animal species: biology and longevity, geographic and spatial distribution, population size and dynamics, feeding habits, role as prey animals of carnivores, interactions with other small mammals, landscape characters of the habitat
	E. multilocularis: prevalence, intensity, and duration of the infection; intensity of protoscolex production; host immunity
Humans and other aberrant hosts	Exposure to eggs, behavior, relationship to carnivores, susceptibility, resistance, and immunity