multilocularis is found primarily in subarctic and arctic regions in
North America,Europe, and Asia. The adult worms are found in the gut of foxes
and, to a lesser extent, coyotes. Their larval forms find harborage in the
tissues of mice and voles, the canines’ rodent prey. Domestic dogs may acquire
adult tapeworms by killing and ingesting these larval-infected sylvatic
rodents. Humans are infected with larval forms through the inges-tion of eggs
passed in the feces of their domestic dogs or ingestion of egg-contaminated
vegetation. Unlike the larval forms of E.
granulosis, those of E.
multilocularis bud exter-nally, producing proliferative, multilocular cysts
that slowly but progressively invade and destroy the affected organs and
The clinical course in humans is characterized by
epigastric pain; obstructive jaun-dice; and, less frequently, metastasis to the
lung and brain, thus closely mimicking a hep-atoma. Serologic tests are usually
positive. Combined drug and surgical treatment often slows the progress of the
disease and relieves symptoms. It is seldom curative.