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

LIFE CYCLE

• Intermediate host– snails aquatic – Melania sp Semisulcospira sp.
• Eggs are laid with in the cyst in which the worms live, escape into the bronchi, the eggs may pass up from the lungs with mucosa and may be found in sputum which has a characteristic rusty colour.
• Animals swallow the mucous and hence eggs are found in the faeces.
• By 2-7 weeks the miracidium hatches, penetrates the snail where it develops into the sporocyst redia and cercaria in 3 months.
• Cercaria comes out the snail which is eaten by crabs/ cray fish (II Intermediate host) to become metacercaria.
• The metacercaria are found mostly in the heart, liver and muscle of II Intermediate host.

Paragonimus westermanii Egg.

Click here to view the life cycle of Paragonimus