|
|
|
Lung (x400). Severe fibrinosuppurative
exudation with destruction of the lung parenchyma
Lung (x200). Chronic healing
lesion with classic bronchiolitis obliterans lesion within airway.
Pneumonic Pasteurellosis:
This is a case of fibrinous (or lobar) pneumonia due
to infection with Pasturella haemolytica.
Although P haemolytica is the usual casue of
this form of fibrinous pemonia in cattle, it can also be casued by P
multocida, and ocassionally Haemophilus
somnus can cause an indistinguishable lesion.
Pnuemonic pasteurellosis frequently occurs in cattles
following the stress of transporataion which has given rise to the common
name for this conditrion - shipping fever.
Transporataion is not, however, the only context in which the disease
is seen. The disease is seen in young calves,
in older calves as an infection superimposed on
enzootic pneumonia, and sporadically in cattle of any age.
Predisposing viral infections are thought to play a
role in the deveopment of pneumonic pasteurellosis. Parainfluenza 3 virus
(PI-3), bovine herpesvirus-1 (BHV-1) and bovine respiratory syncytial
virus (BRSV) are the viruses that have been most often linked to development
of pneumonic pasteurellosis.
Due to the severitiy of the necrotising process associated
with pneumonic pasturellosis, the sequelae can be serious and include
death due to septicaemia, abcesses, sequestra, chronic pleuritis, fibrous
pleural adhesions and bronchiectasis.
Bronchioloitis oblietrans - organising
pneumonia (BOOP) is a common response
to infectious or inflammatory injury to the lungs. It is characterised
by the formation of polypoid plugs of loose, fibrous tissue which fill
bronchioles (bronchiolitis obliterans) and alveoli (organising penumonia).
|
