Taenia crassicceps

969

STUDIES ON THE BIOLOGY OF TAENIA CRASSICEPS (ZEDER, 1800) RUDOLPHI, 1810 (CESTODA)l
REINO

S.

FREEMAN

Abstract
Taenia crassiceps was common in Vulpes fulva examined from southern Ontario. Metacestodes occurred naturally in Micro/us pennsylvanicus, Marmota monax, Tamias siria/uso and Onda/ra zibethicus, and Peromyscus maniculatus, Tamiasciurus hudsonicus. and Sciurus carolinensiswere iníected experimentally; all rodents are new host records. Cysticerci developed into adults in dogs or foxes within 5 to 6 weeks; five coyote pups resisted infection. Development of the metacestode was Collowed mainly in white miee. Infections were most common subclltaneous[y. but also occurred in both body cavities. Mice approximately 4 weeks oC age were most susceptible. Asexualreprodllction occlIrred by exogenous, and rarely endogenolls. blldding from the abscolex pole beginning approximately 3 weeks after infection. Metacestodes in various stages of development were injected into mice subclltaneously, intrapleurally, but mainly intraperitoneally. Subseqllent development and reproduction were similar to that folIowing infection with eggs. Apparently all metacestodes are capable oíbudding. The initial rate oC reprodllction was higher subclItaneollsly and intrapleurally than intraperitoneally, but within approximately 100 days the rate became higher and continued higher intraperitoneally than elsewhere. Reproduction never reached a logarithmic rateo Metacestodes inoculated serially up to 21 times at 50-day intervals increased greatly in size and continued budding. FOllrother series were maintained by serial subinoclllation at 50-day intervals throllgh 23 generations without a significant change in the rate oC reproduction.

Introduction Taenia crassiceps (Zeder, 1800) Rudolphi, 1810 is a common cestode of red foxes (Vulpes vulpes L.) in Europe and the metacestode, Cysticercus longicollis Rudolphi, 1819, has been reported from various small rodents and the mole inEurope. Rausch (15) first reported this cestode from North America, collecting adults from Arctic fox (Alopex lagopus innuitus (Merriam» from the Arctic coast of Alaska, and cysticerci from the lemmings Dicrostonyx groenlandicus richardsoni Merriam and Lemmus t. trimucronatus (Richardson) from Churchill, Manitoba, and the Melville Península, respectively. Little work on the bíology of thisspecies, based on feedíng experiments and study of living material, has be en done since the broad outline of the life history was established by Leuckart (14) and later corroborated by Braun (3, 4, 5), although Studer and Baer (17) indicated that this species can be maintained by intraperitoneal inoculatíon. This cestode was commonly encountered during the present study in the intestines of red foxes(Vulpes fulva (Desmarest» from Ontarío. Eggs fed to various rodents, including. the laboratory mouse, grew into metacestodes, which multiplied by producing buds on the abscolex pole. Metacestodes were maintained also by intraperitoneal inoculation in the intermediate host. Reported here are observations on natural infections in canids and rodents in
lManllscript received :\1ay 15, 1962.Contriblltion Crom Department of Parasitology, Ontario Research Foundation, Toronto, Ontario. This work was made possible by a research grant to the Foundation by the Department of Commerce and Development, Province of Ontario.
Canad¡an Journal of Zoology. Volume 40 (1962)

970

CANADIAN ]OURNAL 01' ZOOLOGY.

VOL. 40, 1962

southern Ontario, and on development of the adult and metacestode invarious hosts under experimental conditions. Study of the susceptibility of white mice of both sexes and various ages, differences in the rate of asexual reproduction subcutaneously and intraperitoneally, and results of continued serial intraperitoneal inoculation are also presented.

Materials and Methods
Aelult cestodes were obtaineel from natural and experimental infections. Frequently the...