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Sheep measles; potentially costly, but easily fixed

Sheep for slaughter are bringing good prices at present. According to experts, this may continue for some time.

At these prices, condemnations at abattoirs because of ‘sheep measles’ are a very expensive proposition. Losing $20.00­–$100 per animal should attract the attention of any producer.

‘Sheep measles’ is the common name for the cysts in the heart and other muscles caused by the larval stages of a particular tapeworm. Sheep and goats can be affected. This larval stage is called ‘Cysticercus ovis’, or ‘C.ovis’.

The adult stage of the tapeworm is called ‘Taenia ovis’. It is about 2 metres long and lives in the small intestine of dogs. Taenia ovis is different from the common dog and cat tapeworm.

Dingoes and foxes play a very minor role in the lifecycle of sheep measles.

Eggs from the Taenia ovis tapeworm are shed in the dung of infected dogs. The eggs, which are very hardy and will survive for long periods on pasture, are ingested by grazing animals.

Inside the sheep, the eggs develop into larvae that produce oval shaped cysts up to 10 mm long in various muscles. The cysts remain for the life of the animal.

Just one cyst found in a carcase at meat inspection leads to mandatory exclusion from export markets and from domestic markets if there are more than a small number.

The life cycle is completed when dogs eat muscle or offal from ‘measles’ affected sheep or goats.

Unlike hydatids, which has a similar life cycle, but is caused by a different tapeworm, sheep measles is not a human health hazard, although it clearly can be a ‘wealth’ hazard.

Key control considerations

Like hydatids, control is based on breaking the sheep-dog lifecycle.

  • Kill tapeworms in the dog by regularly dosing with a tapewormer called praziquantel. This is found in many common dog wormers, but check the fine print.
  • Dogs should be dosed every 4–6 weeks.
  • Prevent dogs from eating offal or meat from sheep or other animals, unless thoroughly cooked.
  • Treat all dogs on the property.
  • Control dogs; prevent straying.

If you follow the above management measures, you will also protect your family and others from hydatid disease.