Effects of some culture factors on sexual differentiation of Mesocestoides corti grown from tetrathyridia in vitro

Abstract Sexually mature adults of Mesocestoides corti were grown consistently from undifferentiated tetrathyridia in vitro . Some ‘conditioning’ of tetrathyridia before cultivation appeared to be necessary for strobilar differentiation. A gas phase of 5% CO 2 /95% N 2 combined with a pH higher than 7.4 provided the most suitable conditions for segmentation and sexual differentiation. Although a diphasic medium was more favourable for asexual differentiation than a monophasic medium, the latter was superior to the former for inducing segmentation. Under optimum conditions, tetrathyridia began segmenting in vitro within 1 week and sexually mature proglottids developed within 5–6 days of segmentation. These results are consistent with the rate of development in the dog. However, eggs containing motile oncospheres were only obtained sporadically. ossible reasons for the low production of embryonated eggs are discussed.