Approach to a dead sheep

Question 1

ABC of sudden death

Answer 1

A - Airway (adrenal)
B - Brain (breathing)
C - Cardiovascular (cellular respiration) (clostridia)

Question 2

Clostridium- general

Answer 2

• Gram positive rods
• Anaerobic
• Form spores on exposure to air
• Produce powerful exotoxins
• Tissue damage/clinical signs relate to effects of the toxin(s) produced

Question 3

Lamb dysentery

Answer 3

Clostridium perfringens Type B
Haemorrhagic necrotising enteritis
- Deep ulcers in the ileum/jejunum
- Gas and frothy fluid filled intestines
- Yellow/haemorrhagic content
- Ascites, serosanginous fluid
Swollen friable liver/kidney
Oedematous mesenteric LLN, focal
Symmetrical encephalomalacia

Question 4

Pulpy kidney disease

Answer 4

Clostridium perfringens Type D
Common, fatal - sheep (lambs)
Enterotoaxaemia - epsilon toxin absorbed from the GI tract
Often well grown lambs, sudden change in diet/improved diet - disturbance of gut flora
Accelerated necrosis of the kidney
Vaccinate ewe- protects lambs for up to 8 weeks

Question 5

Struck

Answer 5

Clostridium perfringens Type C
Lambs at pasture, young adults, changes in diet
Generally found dead
Lethargy, colic, convulsion
Acute, localised enterotoxaemia in SI
Haemorrhaging enteritis
Large volume of straw coloured fluid in peritoneal cavity
Take sample of intestinal content to test for toxin

Question 6

Braxy

Answer 6

Clostridium septicum
Weaned lambs at pasture, first autumn and winter
Eating frosted root crops, changes in diet
Lethargy, colic
Generally found dead - carcase decomposing fast, acute abomasitis
Diffuse purplish area (congestion) or ulceration of abomasal mucous membrane
Take sample of abomasal content

Question 7

Black disease

Answer 7

Clostridium novyi Type B
Migrating flukes, necrosis of liver parenchyma, anaerobic conditions, clostridial multiplication, toxin production
Usually found death
Blood stained fluid in subcutaneous tissues and body cavities
Petechial haemorrhages
Liver looks pale with a cooked appearance, +/- areas of haemorrhage
No inflammation - it is peracute

Question 8

Red gut

Answer 8

Associated with feeding fermentable carbs
More common in older animals on lush, leguminous pasture
Enlarged small and large intestine - displaced or torsed

Question 9

Fasciolis

Answer 9

Migration in the liver leads to necrotic tracts and haemorrhages
Provides the environment for anaerobic Cl. novyi

Question 10

Blackleg

Answer 10

Clostridium chauvoei
Found in intestine and normal tissues, not common in soil
Muscle necrosis, gas bubbles, rancid odour
Gram positive ‘fat’ calls with spores in central position

Question 11

Clostridial myositis

Answer 11

• Malignant oedema (gas gangrene), mixed clostridial infection
• Blackleg (sheep), C. chauvoei
• Blackleg (cattle)

Question 12

Clostridium tetani

Answer 12

Terminal spherical endospores (drumstick appearance)
Found in soil and animal faeces
Infects through wounds
Bacteria do not become systemic, toxin can
Inhibits GABA or glycine release
Treat with surgical debridement of the wound, sedatives, penicillin, and anti-toxin