Coenurosis is a zoonotic disease of humans caused by the larval stage
of Taenia (Multiceps) species. In North America, the adult tapeworm of
Taenia (Multiceps) serialis is found in canids. The cystic larval for
ms (coenuri) are found in hares, rabbits, squirrels, and, rarely, in h
umans. We review in clinical detail the fifth case reported from North
America, involving a child with extensive central nervous system invo
lvement. We also report a sixth case, involving an adult with an intra
muscular coenurus. The latter case was diagnosed by needle aspiration
of the cyst. Although praziquantel administration may have been effect
ive in killing the parasite in both patients, we are concerned about t
he production of marked inflammation as a result of treatment. The fou
r other North American cases are reviewed, and the epidemiology of the
infection in animals is discussed.