Diseases and Parasites of Sheep

General disease control

Sheep are affected by a large number of diseases.  These can be minimised by:

  • Feeding the sheep good food
  • Reducing stress by careful handling
  • Vaccinating sheep against the major diseases. There is a combined Clostridial vaccine which is effective against pulp kidney, lamb dysentery and blackleg.
  • Practice careful hygiene especially at lambing.

Diseases include:

Sheep pox

Sheep pox is a serious viral disease transmitted by contact with other infected animals..  The mortality rate can be high.  The symptoms are small red pimples around the mouth and under the tail accompanied by a high fever.  There is currently no treatment available. Control is by vaccination.


Symptoms are lameness, fever and swelling of the limbs due to gas formation under the skin. Sometimes blackleg occurs at stressful times such as shearing. There is no treatment. Control is by vaccination.

 Enzootic virus abortion

This is an infection disease of sheep leading to abortion in late pregnancy.  Symptoms are abortion in late pregnancy with a retained placenta which leads to uterine infection. Lambs can be born alive or dead.  No treatment is available to prevent abortion, but antibiotics can be given to prevent secondary infections. Control is by vaccination and strict hygienic lambing practices.

 Lamb dysentery

Symptoms are sudden death of young lambs at 2-21 days of age following diarrhoea and fever. Treatment is by serum to reduce death rate. Control is by vaccinating ewes during the last month of pregnancy.

 Joint ill

Symptoms are fever and a swelling of the joints. Antibiotics can be used to treat the disease in the early stages.  Control is by using iodine to disinfect the navel at birth.

 Pulpy kidney

Symptoms are sudden death of an animal which may occur after a change of diet such as at the beginning of the rainy season. Antibiotics are effective in the early stages of the disease. Control is by vaccinating the ewes prior to lambing.



Roundworm Scours, anaemia and wasting Worm or drench weaned lambs regularly in the rains Rotational grazingWorm ewes just after lambing
Tapeworm Wasting & rickets Worm lambs at 6 weeks and at weaning Rotational grazingGraze young stock first
Liverfluke Dullness, distended stomach, anaemia Worm or drench Keep stock off wet pastures and stream banks
Tickas, fleas and scab Parasites on animals Dip or spray Dip regularly

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Written by Fiona Johnson

March 2012