21 Histotoxic Clostridium

Question 1

What disease does C. chauvoei cause?

Answer 1

Black leg

Question 2

What species does black leg effect?

Answer 2

Mostly cattle, rarely sheep

Question 3

What toxin does C. chauvoei produce?

Answer 3

C. chauvoei toxin A (CctA, a 1-beta pore-forming toxin)

Question 4

Describe the pathogenesis of black leg, starting from infection through progression of clinical signs.

Answer 4

C. chauvoei spores ingested from soil –> Intestinal absorption –> enter circulation –> spores use macrophages to enter the muscle –> spores latent in muscle –> blunt trauma (i.e. travel) –> reduced O2 –> germination –> toxin production (CctA) –> muscular necrosis –> toxemia –> shock

Question 5

What are the most common predisposing factors to black leg?

Answer 5

1. Trauma (no skin/mucosa laceration)
2. Toxins (black leg of the heart)

Question 6

With black leg, simultaneous skeletal and cardiac muscle disease is ______ (frequent/infrequent).

Answer 6

Frequent