Hydatids
General description
- Hydatids are the cystic stage of the dog tapeworm Echinococcus granulosus.
- The tapeworm is tiny, only 3 - 6 mm long and lives in the intestines of dogs.
- Hydatids do not affect sheep health or production on farm.
- Hydatid cysts can be fatal in humans. Tapeworm cysts can be found in the liver or lungs (the two most common sites), the brain, kidneys, spleen, heart or other parts of the body. A heavily infested organ may fail, or a cyst may rupture and cause a life-threatening allergic reaction.
Cause
- The larval cyst forms in intermediate host animals such as sheep. Affected sheep organs are condemned at slaughter.
- Kangaroos, wallabies, foxes and feral dogs, deer or pigs can either carry hydatid cysts or harbour the dog tapeworm and therefore maintain an infection cycle on land.
Clinical signs
- Clinical signs in live sheep are rare, unless the cyst is in the brain, when the animal’s movement may be affected. At slaughter infected carcasses may be trimmed or condemned.
Diagnosis
- Cysts cannot be detected on live animals but are readily seen by examining the animal at the abattoir.
- Cysts can occur on the brain, lungs or liver.
Prevention
- Monthly worming of farm dogs (with a product that contains the active ingredient praziquantel), restricting them from access to offal will help prevent hydatids.
- Consider not feeding raw meat to dogs. Raw meat should be cooked or frozen to minus 20℃ for 2 days or longer before feeding. Dogs receiving raw meat should be wormed more frequently.
Treatment
- There is no effective treatment for sheep with hydatid cysts.
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