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

Peoples, Robert C.; Fried, Bernard

doi:10.1007/s00436-008-1209-8

Cited by 2 publications

(1 citation statement)

References 6 publications

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“…The degeneration of inner materials might have induced deformity and reduction of egg volume. A study found deformed eggs when mature Echinostoma caproni gravid adults stored in Locke’s solution up to 4 months at 4°C [8]. One possible explanation for above changes may be improper quinone tanning which is associated to the process of egg shell formation [9].…”

Section: Discussionmentioning

confidence: 99%

Production and Deformation of Clonorchis sinensis Eggs during In Vitro Maintenance

et al. 2012

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Clonorchis sinensis is a carcinogenic human liver fluke. The present study monitored eggs produced by long-term maintained adult worms of C. sinensis to confirm their egg productivity in vitro. The worms from infected rabbits were incubated in vitro in 1× Locke’s solution and broth media (RPMI-1640, DMEM and IMDM). Numbers of expelled eggs were counted sequentially and their morphological changes were monitored by microscopy after 1, 30, 60, and 90 days of cultivation. On the 1–3 days of cultivation, the eggs counted maximum 4,756±202 eggs/worm/day in IMDM medium. The number of eggs gradually decreased less than 1,000 at 7–14 days and below 100 at 21days but continued to pass eggs after 56 days in all media. Length of the eggs were reduced about 1 µm at 30 days, and the length/width ratio was maintained around 1.8 at 30 days but decreased to 1.7 at 60 days and 1.5 at 90 days. Faust-Meleney index (FMI) decreased as the cultivation duration increased and lowest FMI (5662.9±974.7) observed in IMDM media at day 90 (P = 0.001). Microscopic findings of the eggs recognized the miracidium in most of eggs at 60 days but not in those at 90 days. Instead, the eggs contained dark granules or vacuoles in the deformed shell at 90 days. Scanning electron microscopy revealed partial loss of wrinkles on the deformed egg surface and prominent abopercular knob. Eggs viability decreased as the cultivation progressed and showed significant positive correlation with FMI and length/width ratio. In conclusion, the cultivated worms pass only the eggs which are preformed in their uterus before cultivation. One gravid C. sinensis contains about 37,000 eggs in its uterus and produces about 4,000 eggs every day. The deformed eggs with FMI less than 7,000 and length/width ratio lower than 1.7 are non-viable.

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Section: Discussionmentioning

confidence: 99%

Production and Deformation of Clonorchis sinensis Eggs during In Vitro Maintenance

et al. 2012

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Egg-Hatching Mechanism of Human Liver Fluke,Opisthorchis viverrini: A Role For Leucine Aminopeptidases From the Snail Host,Bithynia siamensis goniomphalos

Khampoosa

Jones

Lovas

et al. 2018

Journal of Parasitology

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The human liver fluke Opisthorchis viverrini (Platyhelminthes, Trematoda, Digenea) uses snails of the genus Bithynia as first intermediate host. Peculiarly among trematodes, the eggs of O. viverrini hatch within the digestive tract of its snail host. It remains uncertain whether hatching in this species is mediated through mechanical fracture of the eggshell or by digestion with specific digestive enzymes. This study aimed to characterize enzymes with specific inhibitors and factors involved in the hatching activity of O. viverrini eggs. For measuring egg hatching in vivo, 50 O. viverrini mature eggs were fed to individual Bithynia siamensis goniomphalos snails at various temperature conditions for 24 hr. Ex vivo, mature eggs were incubated with crude snail extract and commercial leucine aminopeptidase (LAP). Egg-hatching of O. viverrini was temperature dependent, with optimal hatching occurring at 24-28 C, with a peak of hatching of 93.54% in vivo and 30.55% ex vivo occurring at these temperatures. Ex vivo hatching rates increased to 45.87% under anaerobic conditions at 28 C. Some 22.70% and 16.21% of heat-killed eggs also hatched within the snail digestive tract and snail extract, respectively, indicating that host molecules are involved in the hatching response. Most eggs hatch in the anterior regions of the digestive tract. Hatching was completely inhibited in the presence of bestatin, an inhibitor of LAP, but not in the presence of phosphatase inhibitors. Bestatin inhibition of hatching was reversible. Finally, egg hatching could be induced by addition of a porcine LAP. The results indicate that this digenean utilizes both LAP of the snail host and movement of miracidia for hatching.

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

Cited by 2 publications

References 6 publications

Production and Deformation of Clonorchis sinensis Eggs during In Vitro Maintenance

Production and Deformation of Clonorchis sinensis Eggs during In Vitro Maintenance

Egg-Hatching Mechanism of Human Liver Fluke,Opisthorchis viverrini: A Role For Leucine Aminopeptidases From the Snail Host,Bithynia siamensis goniomphalos

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