Temperature dependent embryonic development of Trichuris suis eggs in a medicinal raw material

Both male and female pigs were used to evaluate eventual gender specific infectivity. Storage at 30 °C up to 14 weeks and subsequent embryonation for 14 weeks at 25 °C did not significantly reduce the overall larval establishment in minipigs, as compared to storage at 5 °C and subsequent embryonation at 25 °C. As marked impairment of egg development was observed during storage at 40 °C, a second set of unembryonated egg batches were incubated at 30, 32, 34, 36, 38, and 40 °C (±1 °C) for 1-8 weeks. The development of the eggs was repeatedly examined by manual light microscopy, multispectral analysis (OvaSpec), and an egg hatching assay prior to the final testing in minipigs (Trial 1). These methods showed that the development started earlier at higher temperatures, but the long-term storage at higher temperature affected the egg development. The present study further documents tolerance of the TSO to storage at temperature 5-15 °C, at which temperature development of larvae is not initiated.