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

LIFE CYCLE

• Eggs are passed in the faeces of host, they are light brown in colour, operculated and unembryonated when laid.
• The development of eggs occur in the environment, takes several weeks for the development of ‘coracidium’. It is a six hooked oncosphere covered with ciliated embryosphore.
• The fully developed coracidium hatch out and swim in the water for short period then the coracidim is ingested by 1^st I/H – Cyclops in which develops into “Procercoid” in about 3 weeks time. These infected 1^st I/H are ingested by fish (2^nd I/H).
• Within the 2^nd I/H it develops into plerocercoid in the viscera and musculature.
• D/H acquire infection by eating of infected raw fish. Prepatent period is 4 weeks

Diphyllobothrium_egg

Click here to view the lifecycle