Effects of prolonged worm storage on the viability of Echinostoma caproni eggs

This study examined the effects of long-term worm storage on the viability of Echinostoma caproni eggs. Gravid adults (referred to as worm carcasses or WCs) were maintained in Locke's 1:1 at 4 degrees C for 2, 4, 6, 8, 10, and 12 months prior to use. When used, about 100 eggs at each time interval were tested for viability by embryonating them at either 22 +/- 1 degrees C for 14 days or 28 degrees C for 10 days in artificial spring water. Viability was determined by detecting fully developed miracidia in the eggs or miracidia in the cultures at the above-mentioned time periods. There was a high percentage of fully developed eggs from WCs stored in Locke's 1:1 at 4 degrees C for 2 and 4 months, 92% and 71%, respectively. Beyond these times, there was a marked decline in egg viability. We suggest that WCs should not be stored for longer than 4 months in Locke's 1:1 at 4 degrees C to obtain optimal embryonation and hatching of E. caproni.