VPA 211: General Veterinary Parasitology and Helminthology (3+1)

EGG OF TREMATODES

• Usually the trematode eggs have operculum - a lid or cap like structure at the anterior end. But schistosome egg has terminal spine.
• In most of the species, the eggs are developed in the uterus, so they are ready to hatch immediately after laying.
• Generally the trematode eggs hatch in the water but in Dicrocoelium dendriticum, the egg hatch only after ingested by the snail intermediate host.
• Hatching of eggs is controlled by number of factors like light, temperature and salinity of water.
• Eggs cannot with stand desiccation. Under favourable condition larvae hatches out from the eggs.

Example

Fasciola Egg.	Amphistome Egg.	Paragonimus Egg.

Schistosome Egg.