INFECTION COURSE OF THE STROBILAR STAGE OF TAENIA-CRASSICEPS IN GOLDEN-HAMSTERS, WITH REFERENCE TO HOST RESPONSES

The time course of intestinal infection of golden hamsters (Mesocricet us auratus) with Taenia a crassiceps was monitored every 2 days up to day 26 postinfection (p.i.). The isolate used was originally obtained from Clethrionomys rutilus on St. Lawrence Island, Bering Sea (USA), a nd shows a high level of enteral establishment without parenteral infe ction. Following oral administration of various numbers (3, 15, 30, or 60) of metacestodes, proportional numbers of cestodes attached their scolices to the mucosa of the middle (one-third) segment of the small intestine. Except for animals given 3 metacestodes, dislocation of ces todes to the posterior parts of the intestine was noted on days 10-14 p.i. and began faster in animals that had received larger numbers of m etacestodes. Concurrent with dislocation or elimination of cestodes, t here existed distinct increases in intestinal eosinophil peroxidase an d myeloperoxidase activities. The number of mast cells in the lamina p ropria peaked on day 16 p.i., and specific serum IgG began to increase within 1 week p.i. The level of all these changes was dose-dependent. In prednisolone-treated animals that received 60 metacestodes, disloc ation of cestodes was not evident, and mucosal inflammatory changes we re suppressed to a considerable extent. The findings of this study are discussed as a model for the study of canine taeniasis.