The clinical consequences of tapeworm infection in
humans depend on whether the patient serves as the primary or the intermediate
host. In the former case, the adult worm is confined to the lumen of the gut,
and the consequences of the infection are typically mi-nor. Taeniasis saginata
and diphyllobothriasis are prime examples. In contrast, when the patient serves
as the intermediate host (eg, for E.
granulosus), larval development pro-duces tissue invasion and frequently
serious disease. The capacity of H. nana
and T.solium to use humans as both
primary and intermediate hosts is unique.