Liver fluke in cattle and sheep
What is liver fluke?
- Caused by the fluke Fasciola hepatica.
- Disease results from movement of immature flukes through the liver, or from the adult flukes in the bile ducts, or both.
- Affects both cattle and sheep.
- Beef cows more likely to be affected than dairy, especially if grazing wet pasture.
- A year round problem.
Fluke life cycle:
- Liver fluke survival depends on the presence of a mud snail, Limnea truncatula.
- Fluke eggs hatch to form miracidia which infect the snails.
- The fluke grow inside the snails to become the next life stage (Cercaria).They then leave the snails between August and October.
- They develop on pasture into the life stage which can infect grazing cattle and sheep (metacercariae). These can survive on pasture for several months until eaten.
- Once inside a cow or sheep, the immature fluke grow inside the intestine. They then migrate into the abdomen and head to the liver and bile duct. This takes about six to eight weeks and causes extensive damage to the liver tissue.
- Egg-laying adults will have developed 10-12 weeks after ingestion.