Bladder worm
General description
- Bladder worms are large cysts found on the liver and in the abdominal cavity of sheep caused by the ingestion of eggs from the dog tapeworm Taenia hydatigena.
Cause
- Sheep become infected by ingesting tapeworm eggs from contaminated pastures.
Clinical signs
- Sheep will show no clinical signs.
Diagnosis
- Cysts cannot be detected in live animals but are readily seen by examining the animal at the abattoir.
- Bladder worm cysts have a thin wall, are 1-6 cm in diameter and are filled with clear fluid.
- They occur on the liver, diaphragm and abdominal organs and tissues.
- Before cysts are formed, the migrating stages cause bloody tracts in the liver tissue.
Treatment
- There is no effective treatment for sheep with bladder worm cysts.
- Treatment is not necessary as the cysts cause no economic or production loss and are not a human health risk.
Prevention
- Monthly worming of farm dogs, restricting them from access to offal and uncooked sheep meat will help prevent false hydatids.
- Control wild dogs.
