Pasteurellosis (Pasteurella multocidia)

Background and history

Pasteurella multocida bacteria are commonly involved in respiratory disease in pigs and they may be toxin-producing or non-toxin-producing strains. Either can cause pneumonia in their own right but the non toxin ones are common secondary opportunist invaders associated with primary EP or PRRS infections. Pasteurella multocida type A causes pneumonia.

Clinical signs

Acute disease

  • Severe sudden pneumonia affecting all the lung tissue.
  • High temperatures.
  • Discharges from the nose.
  • High mortality.
  • Pigs show rapid breathing.
  • Blue discoloured skin particularly on the extremities of the ears (caused by toxins or heart sac infections).

Sub-acute disease

The condition usually affects pigs between 10 and 18 weeks of age.

  • Pneumonia which is less severe but often complicated by heart sac inflammation and pleurisy.
  • Coughing.
  • Discharges from the nose.
  • Emaciation. Poor body condition / wasting.
  • Increased mortality.


This is carried out by post-mortem examination and isolation of the organism from the lungs.


Concurrent disease such as PRRS, Flu and EP predispose.


  • Carry out procedures as described under respiratory diseases and control strategies.
  • Vaccines are available but are not very effective.
  • EP vaccination often prevents the pasteurella invading the lungs.


Infection with Pasteurella bacteria is usually secondary to a more specific disease antibiotic treatments should follow as for enzootic pneumonia.