Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
New page: right|thumb|100px|<small><center>Blackleg myositis (Image sourced from Bristol Biomed Image Archive with permission)</center></small> *Causative agent: ''...
[[Image:Black leg myositis.jpg|right|thumb|100px|<small><center>Blackleg myositis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Causative agent: ''[[Clostridium chauvoei]]''
*May affect the fattest cattle at pasture in the summer
*Rapid toxaemia -> death
*If clinical signs observed:
**Toxaemia -> pyrexia, depression, [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]], circulatory collapse
**Muscle lesions -> lameness, swollen hot muscles later becoming cool as necrosis sets in
*Pathogenesis:
**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
*Grossly:
**Early stages
***At muscle periphery
***Dark red
***Distended by serous or serosanguinous exudate
***Wet cut surface
**Old stages
***Centre of lesion is full of gas bubbles, porous, dry, reddish black
***Rancid odour
*Histologically:
**Early stages
***Separation of myofibres by exudate
***[[Necrosis - Pathology#Coagulation Necrosis|Coagulative necrosis]]
***No nuclei
**Old stage
***Fragmented muscle fibres separated by gas bubbles
***Gram positive bacilli may be found in clumps
[[Category:Sheep]][[Category:To_Do_-_Clinical]]
*Causative agent: ''[[Clostridium chauvoei]]''
*May affect the fattest cattle at pasture in the summer
*Rapid toxaemia -> death
*If clinical signs observed:
**Toxaemia -> pyrexia, depression, [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]], circulatory collapse
**Muscle lesions -> lameness, swollen hot muscles later becoming cool as necrosis sets in
*Pathogenesis:
**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
*Grossly:
**Early stages
***At muscle periphery
***Dark red
***Distended by serous or serosanguinous exudate
***Wet cut surface
**Old stages
***Centre of lesion is full of gas bubbles, porous, dry, reddish black
***Rancid odour
*Histologically:
**Early stages
***Separation of myofibres by exudate
***[[Necrosis - Pathology#Coagulation Necrosis|Coagulative necrosis]]
***No nuclei
**Old stage
***Fragmented muscle fibres separated by gas bubbles
***Gram positive bacilli may be found in clumps
[[Category:Sheep]][[Category:To_Do_-_Clinical]]