Lung worm

General description

  • There are two different types of worms that infest the lungs of a sheep, large lungworms and small lungworms. Large lungworms cause most of the disease seen in sheep – they live in the airways. Small lungworms live in the lung tissue.


  • Lungworms are most prevalent in the cooler, wetter areas of southern Australia, generally in autumn or winter.
  • Lambs 4-6 months of age are most severely affected however it can be seen in sheep of any age.

Clinical signs

  • A moderate to heavy infestation of lungworms causes irritation to the lining of the airways and a cough.
  • A very heavy lungworm burden may cause breathing difficulty, nasal discharge, reduced milk yield, ill thrift, pneumonia, suffocation and death.


  • Lungworms can be identified in a faecal egg count and culture.
  • On post mortem, lungworms can be seen in the airways and lungs.


  • Many of the sheep drenches are registered for the treatment of lungworms.


  • Ensure an adequate drenching program is carried out regularly.

Learn more

NSW DPI primefacts - Lungworms in cattle, sheep and goats

Worms - lungworm