This disease primarily affects piglets, weaners and growers. The key clinical signs include septicaemia; pneumonia; head to one side.
calendar icon 15 November 2018
clock icon 6 minute read

Background and history

This is caused by the bacterium Listeria monocytogenes which may colonise the tonsils and be passed out in faeces.

Listeria are wide spread in nature and are often found in cheese and silage.

Exposure results in infection but disease is uncommon.

Clinical signs

  • The bacterium may cause a septicaemia and high temperature in piglets.
  • Nervous signs, possibly meningitis.
  • Weak piglets at birth.
  • Pneumonia.
  • Head on one side.
  • Middle ear infections.


Laboratory examinations are necessary for diagnosis. Polymerase chain reaction (PCR) tests are used.


  • Stress causing the bacteria to invade the system.
  • Porcine reproductive and respiratory syndrome (PRRS).
  • Flu.
  • Heavy environmental exposure


  • Listeria are usually sensitive to penicillin and ampicillin.
  • In outbreaks it is necessary to identify the sources of infection and reduce the exposure to them.

Emily Houghton

Editor, The Pig Site

Emily Houghton is a Zoology graduate from Cardiff University and was the editor of The Pig Site from October 2017 to May 2020. Emily has worked in livestock husbandry, and has written, conducted and assisted with research projects regarding the synthesis of welfare and productivity of free-range food species.

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