PATHOLOGY - Sudden Death in Lambs Flashcards
What are the differential diagnoses for sudden death in growing lambs?
Anthrax
Clostridial disease
Pasteurellosis
Acidosis
Acute liver fluke
Polioencephalomalacia
Obstructive urolithiasis
Nematodirus
Coccidiosis
Redgut
Toxicity
White muscle disease
Trauma
Which envrionments are clostridia associated with?
Clostridia are associated with anaerobic, acidic environments
Think in terms of blackleg in anaerobic wounds etc.
Which clostridial diseases can cause sudden death in sheep?
Pulpy kidney disease
Blackleg
Tetanus
Black disease
Braxy
Clostridium sordelli
Which pathogen causes pulpy kidney disease?
Clostridum perfringens type D
What is the pathogenesis of pulpy kidney disease?
Clostridium perfringens type D is a commensal bacteria of the intestines of sheep. However, when shee consume large amounts of carbohydrate rich food (such as milk in nursing lambs and concentrates in weaned lambs), this can create an environment that favours the overgrowth of C. perfringens type D. As these bacteria proliferate, they produce epsilon (ɛ̝) toxin, which is a potent exotoxin which is absorbed through the intestines and into the bloodstream. ɛ̝ toxin causes pore formation in the vascular endothelial cells resulting in haemorrhage and perivascular oedema. This toxin particularly affects the brain, kidneys and liver. Furthermore, there will be increased mobilisation of the hepatic glycogen stores resulting in hyperglycaemia and glycosuria
What is the typical signalement for pulpy kidney disease?
4 week to 8 month old, unvaccinated (for clostridial disease) lambs in good condition. This is typically seen in lambs recently exposed to a rich diet
What is the general clinical presentation of pulpy kidney disease?
Sudden death
What are the potential clinical signs of pulpy kidney disease (rare to see alive)?
Severe depression
Abdominal pain
Grinding teeth
Neurological signs
How can you diagnose pulpy kidney disease?
History (usually moved on rich diet/pasture)
Post mortem (PM)
Culture
ELISA for ɛ̝ toxin
What are the post mortem findings for pulpy kidney disease?
Good body condition
Clear fluid in the body cavities
Fluid in the small intestine
Petechiae on the lungs and pericardium
‘Pulpy kidneys’
Focal, symmetrical haemorrhages in the basal ganglia of the brain
Focal, symmetrical encephalomalacia
Glycosuria
How can you prevent pulpy kidney disease?
Clostridial vaccination
Introduce rich diets gradually
What is tetanus typically associated with in sheep?
Tetanus is typically associated with lamb tail docking and castration wounds which allow the tetanus toxin to infiltrate the body
Which pathogen causes black disease?
Clostridium novyi
What is the pathogenesis for black disease?
Clostridium novyi is a spore-forming bacterium that is a commensal bacteria intestines of sheep, and in the environment, particularly in soil. Black disease is typically associated with liver damage, such as migration of liver fluke as this provides a favorable environment for the germination of c.novyi spores, allowing them to multiply and produce α and β exotoxins which result in necrosis and characteristic blackening of tissues
What is the typical signalement for black disease?
Black disease can affect sheep of all ages. There is an increased risk of this disease in sheep with liver fluke. Thus this disease is more common in autumn
How can you prevent black disease?
Clostridial vaccination
Control liver fluke
Which pathogen causes braxy?
This disease is not as common
Clostridium septicum
Causes abomasitis
What is the typical signalement for braxy?
Young sheep grazing on frosted forage
Which clinical disease can clostridium sordelli cause in young lambs?
Clostridium sordelli can cause acute abomasitis in lambs 3 to 10 weeks old
Which clinical disease can clostridium sordelli cause in finishing lambs?
Clostridium sordelli can cause acute abomasitis and sudden death in lambs 6 to 12 months old
How do you treat clostridial disease?
Penicillin
What is the key preventative strategy for clostridial disease?
Clostridial vaccination
Should vaccinate preventatively but should also vaccinate any unvaccinated individuals if disease starts to occur on the farm
What is the vaccination protocol for clostridial vaccinations?
- Booster vaccinate the pregnant ewes 4 - 6 weeks pre-lambing (to provide antibodies agaisnt clostrida in the colostrum)
- Vaccinate lambs at 10 weeks old (as maternal antibodies will only last for 10 weeks)
- Booster vaccinate lambs 4 - 6 weeks later
What is the clostridia vaccination protocol for the progeny of ewes that have not had the clostridial vaccine?
If the ewes haven’t had the clostridial vaccination, you should vaccinate their progeny at 2 weeks old and then give a booster 4 - 6 weeks later
Which pathogen causes septicaemia pasteurellosis?
Mannheimia haemolytica
Gram negative, fastiduous
What is the typical signalement of septicaemic pasteurellosis?
Lambs up to 12 weeks old, in good condition
What is the typical clinical presentation of septicaemic pasteurellosis?
Sudden death
What are the potential clinical signs of septicaemic pasteurellosis (rare to find them alive)?
Severe depression
Severe pyrexia (over 41°C)
Toxic mucous membranes
Dyspnoea
Which pathogen cause systemic pasteurellosis?
Pasteurella trehalosi
Gram negative, fastiduous
What is the typical signalement of systemic pasteurellosis?
Recently weaned lambs (animals are stressed at weaning)
What is the typical clinical presentation of systemic pasteurellosis?
Sudden death
What are the potential clinical signs of systemic pasteurellosis (rare to find them alive)?
Severe depression
Severe pyrexia (over 41°C)
Toxic mucous membranes
Dyspnoea
How can you diagnose septicaemic or systemic pasteurellosis?
History
Clinical signs
Post mortem (PM)
How can you treat septicaemic and systemic pasteurellosis?
Antibiotics
How can you prevent septicaemic and systemic pasteurellosis?
Vaccination
What causes acidosis in sheep?
Acidosis is caused by sudden or unaccustomed high intake of rapidly fermentable carbohydrates (grain overload), resulting in increased fermentation, ruminal acidosis and metabolic acidosis
What are the potential clinical signs of acidosis in sheep?
Sudden death
Anorexia
Teeth grinding
Abdominal distension
Abdominal pain
Ruminal stasis
Tachypnoea
Hyperpnoea
Diarrhoea
Toxic mucous membranes
Dehydration
How can you diagnose acidosis in sheep?
History
Clinical signs
Post mortem (PM)
What are the typical post mortem changes associated with acidosis in sheep?
Milky grey ruminal contents with rancid odour
Ruminal epithelium sloughing off
Rumen pH less than 5.5
How can you treat acidosis in sheep?
Euthanasia
How can you prevent acidosis in sheep?
Gradual introduction of carbohydrate rich feed
Good quality roughage available
Close feed stores (don’t allow animals to break into feed stores)
