Respiratory Bacterial Infections - Pathology

()Map CARDIORESPIRATORY SYSTEM (Map) RESPIRATORY SYSTEM INFLAMMATION

In general

• Main clinical expression is as secondary invaders of previously damaged lung tissue due to viral or parasitic involvement or environmental stress
• Some are initial pathogens in their own right while others can damage the tract allowing invasion by more pathogenic types

In Dogs

Infectious Canine Tracheitis

In Cats

In Horses

In Cattle

Necrotic Laryngitis

Cillia-associated Respiratory Bacillus

In Sheep

CAR bacillus

• As in cattle

In Pigs

Necrotic laryngitis in pigs

• As in cattle
• Caused by infection with Fusobacterium necrophorum

Pasteurellosis in pigs

• Pasteurella multocida can cause a severe acute fibrinous bronchopneumonia in pigs
• The most significant disease here is that caused by P. multocida secondary to underlying mycoplasma pneumonia, see above enzootic pneumonia of pigs
  • This results in chronic suppurative bronchopneumonia with abscessation and pleuritis
• If there is considerable pleural involvement, it may be indistinguishable from lesions caused by Haemophilus pleuropneumonia (below)
• Also isolated from cases of meningitis and septicaemia in piglets

Contagious porcine pleuropneumonia

• Caused by Haemophilus (Actinobacillus) pleuropneumonia
• Seen mainly between 6wks-6mths of age but will affect any age
• Highly pathogenic strains are capable of initiating disease on their own with high mortality in young pigs
• A fibrinonecrotic bronchopneumonia with pleurisy
• Foci of haemorrhagic consolidation or necrosis, mainly around major bronchi, tend to sequestrate
• Tending to spread throughout all lung lobes: therefore a cranioventral distribution may not be particularly evident

Glasser's disease

• Caused by Haemophilus parasuis
• May cause suppurative bronchopneumonia and pleuritis (as part of polyserositis)
• Stress of mixing, weaning and adverse environmental conditions are predisposing to the disease

Streptococcal pneumonia

• Caused by Streptococcus suis type II

Tuberculosis in pigs

• Pigs are susceptible to the Mycobacterium spp. causing tuberculosis in cattle
• Rarely extends to lungs after haematogenous spread from ingested bacteria causing tubercles with various degrees of calcification, encapsulation and caseation

In Rabbits

Snuffles

• Caused by Pasteurella multocida, less commonly and/or Bordetella bronchiseptica
• Clinical signs (nasal discharge, sneezing) result from an acute to chronic rhinitis

CAR bacillus

• As in cattle