INTRACAPSULAR ASEXUAL PROLIFERATION OF MESOCESTOIDES SP TETRATHYRIDIAIN THE GASTROINTESTINAL-TRACT AND MESENTERIES OF THE PRAIRIE RATTLESNAKE (CROTALUS-VIRIDIS-VIRIDIS)

Nonproliferous and proliferous tetrathyridia (Mesocestoides sp.) have been reported from natural and experimental infections in reptiles and rodents. Multiple tetrathyridia (1+) in individual capsules (host-der ived) were observed for both types of tetrathyridia and in both types of animals. To determine whether proliferous tetrathyridia in this gen us could replicate in host capsules of the prairie rattlesnake (Crotal us viridis viridis), 11 snakes were inoculated and maintained in 2 env ironmental chambers (25 C and 30 C). One snake at each temperature was removed at 4-wk intervals and killed. Sections of the gastrointestina l tract and adjacent mesenteries were histologically examined. The inc rease in the numbers of tetrathyridia per capsule was significant at b oth 25 C (P = 0.007) and 30 C (P < 0.001). Identification of 7 intraca psular tetrathyridia with binary scoleces served as collaborative evid ence. This paper presents the first significant evidence for asexual r eplication of the proliferous tetrathyridia (Mesocestoides sp.) in a r eptilian host.