NAVLE Practice Question - Porcine - gastrointestinal/digestive
NAVLE Practice Question — Porcine
During an acute outbreak of C. perfringens type C enteritis in neonatal piglets, which immediate intervention would be most effective for protecting unaffected piglets that have already been born?
A. Oral ampicillin administration to unaffected piglets
B. Administration of hyperimmune type C antitoxin within 2 hours of birth ✓
C. Vaccination of affected piglets with type C toxoid
D. Environmental application of quaternary ammonium disinfectants
E. Immediate weaning of unaffected piglets
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Correct Answer: B. Administration of hyperimmune type C antitoxin within 2 hours of birth
Explanation:
The correct answer is B. During an acute outbreak, administration of type C antitoxin (hyperimmune serum containing antibodies against beta toxin) provides immediate passive protection to at-risk piglets. When given within 2 hours of birth to piglets that have not yet developed clinical signs, antitoxin can provide complete protection against disease development.
The antitoxin provides immediate neutralization of beta toxin, preventing tissue damage even if the piglet has been exposed to C. perfringens type C. This is crucial because once clinical signs develop, treatment is largely ineffective due to the irreversible nature of the intestinal lesions.
Option A (oral ampicillin) can be used prophylactically and may help reduce bacterial proliferation, but it does not neutralize existing toxin and is less immediately effective than antitoxin.
Option C (vaccination of piglets) would not provide protection during an acute outbreak; vaccines require time to stimulate an immune response and neonates cannot mount effective active immunity rapidly enough.
Option D (disinfectants) helps reduce environmental contamination but does not protect currently at-risk piglets.
Option E (immediate weaning) would deprive piglets of colostral antibodies if the sow is vaccinated and would likely worsen outcomes.
For longer-term control, sow vaccination and improved hygiene are essential.
References: Merck Veterinary Manual - Clostridium perfringens Type C Enteritis in Pigs; Pig Progress - Clostridial Infection
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