Changes

In cattle it is typically beef breeds who are affected particularly animals in good health and good body condition. More frequently occurs in cattle between 6-24 months old but can affect animals of any age. In some animals lesions occur following muscle trauma, which is thought to activate latent spores in the muscle.

In cattle it is typically beef breeds who are affected particularly animals in good health and good body condition. More frequently occurs in cattle between 6-24 months old but can affect animals of any age. In some animals lesions occur following muscle trauma, which is thought to activate latent spores in the muscle.

In sheep, cases typically occur following some form of injury such as shearing cuts, docking or castration.

In sheep, cases typically occur following some form of injury such as shearing cuts, docking or castration.

==Diagnosis==

==Diagnosis==

==History and Clinical Signs==

==History and Clinical Signs==

Spores gain entry to GI tract -> blood -> muscle -> lie latent. Under right conditions (usually anaerobic following injury) they germinate and bacilli grow. Toxin damages capillaries -> serosanguinous exudate. Muscle necrosis due to gas producing bacteria -> emphysaema and crepitus

Spores pass through the wall of the GI tract and via the bloodstream enter the muscle where they then lie latent. Under the correct conditions (usually anaerobic following injury) they germinate and bacilli grow. Toxins damage the capillaries causing a serosanguinous exudate. Muscle necrosis occurs due to gas producing bacteria resulting in emphysaema and crepitus

The bacteria can cause rapid toxaemia resulting in death, however if clinical signs do occur these can include toxaemia, pyrexia, depression, [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]], circulatory collapse

The bacteria can cause rapid toxaemia resulting in death, however if clinical signs do occur these can include toxaemia, pyrexia, depression, [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]], circulatory collapse lameness and swollen hot muscles which later become cool as necrosis occurs.

lameness and swollen hot muscles later becoming cool as necrosis occurs.

 

 

In the early stages the musce periphery appears dark red and is Distended by serous or serosanguinous exudate. Is wet on the cut surface

**Early stages

and the centre of the lesion is full of gas bubbles, porous, dry, reddish black

***At muscle periphery

***Dark red

***Distended by serous or serosanguinous exudate

***Wet cut surface

***Centre of lesion is full of gas bubbles, porous, dry, reddish black

***Rancid odour

***Rancid odour

*Histologically:

*Histologically:

**Early stages

In the early stages separation of the myofibres by exudate can be seen which progresses to [[Necrosis - Pathology#Coagulation Necrosis|Coagulative necrosis]] No nuclei

***Separation of myofibres by exudate

***[[Necrosis - Pathology#Coagulation Necrosis|Coagulative necrosis]]

***No nuclei

**Old stage

**Old stage

***Fragmented muscle fibres separated by gas bubbles

***Fragmented muscle fibres separated by gas bubbles

***Gram positive bacilli may be found in clumps

***Gram positive bacilli may be found in clumps

[[Category:Sheep]][[Category:To_Do_-_Caz]]

[[Category:Sheep]][[Category:To_Do_-_Caz]]