Clostridial Disease in Ruminants

Question 1

What type of organism is clostridia?

Answer 1

Ubiquitous organisms

• Gram+, anaerobic bacilli
• Produce spores

Question 2

Where is clostridia found? (3)

Answer 2

•Soil, rotting vegetation, decomposing matter

Question 3

Where is clostridia a commensal?

Answer 3

The gut of livestock

Question 4

What are the trigger factors of clostridia? (4)

Answer 4

• Management: diet change (especially in sheep)
• , handling (handling the mucosa allowing the bacteria in)
• Parasites : e.g. fluke
• Injury – allows the spores in and produce toxins

Question 5

Why is it hard to know the incidence/prevalence of clostridia?

Answer 5

•Sudden and sporadic death; carcasses disposed of without investigation – we would look for anthrax but then if we don’t find this we don’t look for much more! (Hard to look for prevalence and incidence- see lecture later)

Question 6

What are the 3 different types of clostridia?

Answer 6

Lamb dysentery (B) – Middle common

Struck (C) – Least common

Pulpy kidney (D) – Most common

Question 7

What are the predisposing factors for clostridia (5)

Answer 7

• Low proteolytic activity in neonatal intestine (trypsin inhibitors in colostrum)
  
  • Certain types are predisposed to different ages due to this
• Incomplete establishment of normal flora in neonates
• Dietary influences
  
  • Frosty paddocks – thought might trigger clostridium?
  • Increased concentrate?
  • Change from milk to roughage?
• Abrupt diet change, gorging energy rich diet
  
  • Struggle to deal with this
• Intestinal hypomotility, consequence of overeating

Question 8

Which is the most common enterotoxaemia?

Answer 8

Pulpy kidney (C. perfringens type D)

Question 9

Pulpy kidney (C. perfringens type D):

A) Which animals are affected?

B) What toxin is present?

C) What is found on PM?

D) What are the clinical signs?

Answer 9

A) Growing (4-10 weeks) & Finishing (>6 months)

B) ε toxins (specific)

C) Rapid (kidney) autolysis

D) Often found dead, neurological signs

Question 10

Lamb dysentery (C. perfringens, type B):

A) Where is it seen?

B) What are the clinical signs?

Answer 10

A) Lambs <1-2 weeks of age

B) Haemorrhagic enteritis with ulceration in small intestine

• Usually found dead
• Abdominal pain, Collapse, Blood-stained scour, CNS signs
• Severe picture

Question 11

Struck (C. perfringens, type C):

A) What is seen on PM?

B) Who is affected?

C) What season is it associated with?

Answer 11

A) Necrotic enteritis, jejunal ulceration (on PM – quite typical)

•Usually found dead

B) Neonates & adult sheep

C) Spring grass?

•Frosty in the morning? No evidence yet but thought to be to do with the diet change.

Question 12

How can we diagnose clostrdia peringens?

Answer 12

Diagnosis from acutely affected (euth/dead)

Post mortem (NEED THIS ideally from recent death or euthanise a very ill one and PM – a dead animal will overgrow in any dead sheep (Normal GI tract commensal)):

Carcass or gut contents asap

Isolation of C. perfringens means nothing

Culture on its own not useful

Get relevant suspect history!

•Crucial to have this with the PM results

Question 13

What is seen on PM with pulpy kidney?

Answer 13

cerebral lesions (focal encephalomalacia)

Question 14

What is seen on PM with lamb dysentry?

Answer 14

ulcerations intestinal mucosa

Question 15

How can we use ELISA for diagnosis?

Answer 15

3 toxins (α, β, ε) of C. perfringens

Question 16

What is seen histologically with clostridia?

Answer 16

Gross pathology, confirmed by histopathology with IFAT on tissue

Question 17

Discuss the prevalance of enterotoxamia in cattle

Answer 17

• Uncommon cause of sudden death cf. sheep
• Described in pre-weaned calves and yearling replacement heifers most of the time
• Adult cattle – less likely unless there is an underlying (calving may get a lesions and cause)
• Enterotoxaemia – very rare!
• Similar clinical signs and sudden death
• Haemorrhagic bowel syndrome?

Question 18

Braxy, C. septicum:

A) When is it seen?

B) What is the onset?

C) What are the signs?

Answer 18

A) Seen in autumn and winter; Frosted feeds, microclimate

B) Sudden onset

C) Pyrexia and colic, coma and death

•Abomasitis

Question 19

Black disease, infectious necrotic hepatitis, C. novyi type B:

A) Where is it seen?

B) What is the trigger?

C) What is characteristic on PM?

D) What is seen on impression smears?

Answer 19

A) Sporadic deaths; older sheep, rarely cattle

B) Trigger: Fluke larvae migration

C) Hepatic necrosis; characteristic lesions at PM (sharply delineated yellow necrotic areas of liver) / evidence of migratory fluke

D) IFAT on impression smears

Question 20

Discuss the association of fluke with black disease

Answer 20

•Fluke = liver damage = anaerobic damage = clostridia takes opportunity

Question 21

Where does botulism come from?

Answer 21

Poultry litter – probably has some dead chickens in too

Silage with dead rat

Question 22

What is the difference between tetanus and botulism?

Answer 22

Tetnus – spasms, third eyelid protusion

Botulism – Flaccid, tongue hanging out

Question 23

How can you treat clostridia?

Answer 23

• EARLY!! antibiotics (penicillin), NSAIDs
• Most of the time it is too late and they are dead anyway
• Keep an eye and if there is malignant oedema – need to have at least 5 days AB!

Question 24

What iis the prognosis of clostridia?

Answer 24

depends on how early treatment starts, generally poor

Question 25

How can you prevent clostridia?

Answer 25

• Vaccination – all but black disease are toxins for produce vaccine! (most others have questionable efficacy) But as there are toxins this means these are very effective and they are very consistent –with low antigenic variability
• Management:
• Don’t change the diet suddenlt
• Low stress environment
• Stocking density
• Reduce the chances of lesions
• Good quality feed – reduce mucosa damage
• Good quality equipment to prevent skin damage

Question 26

Why are vaccines so good?

Answer 26

• Vaccines are readily available! AND CHEAP!!
• Breeding ewes and cows vaccinated prior to lambing
• AB transfer in the colostrum is good!
• E.g. Lamb dysentry really affects them in the first few weeks of life!
• all but black disease are toxins for produce vaccine! (most others have questionable efficacy) But as there are toxins this means these are very effective and they are very consistent –with low antigenic variability

Question 27

Which 3 animals should we vaccinate?

Answer 27

• Breeding ewes and cows vaccinated prior to lambing
• Also camelids! Quite likely to get clostridia disease
• Vaccines are not registered but there is not hesitation in using these

Question 28

Why may vaccination efficacy not be as good as it could be? (8)

Answer 28

• Improper storage
• Clostridia vaccine has to be stored 2-8 degrees
• Administration

–Incorrect route

–We don’t know yet if going neck or body for example makes a difference

–MUST VACCINATE IM OR SC IF IT SAYS

–Not given at all!

–Timing

–No booster

–Wrong product!

–Other products given concurrently

•Unfit, poor condition animals – the animal immune system is going to need to work

Question 29

What is a common sequel to infection?

Answer 29

Sudden death..