ICVA Small Ruminant Herd Health 3 — Questions and Answers
Question 1: Contagious ecthyma (orf) in sheep and goats is caused by which type of pathogen?
- Poxvirus (Parapoxvirus) (Correct answer)
- Herpesvirus
- Picornavirus
- Paramyxovirus
Correct answer: Poxvirus (Parapoxvirus)
Contagious ecthyma is caused by Orf virus, a Parapoxvirus, which produces proliferative pustular lesions primarily around the mouth, lips, and teats.
Question 2: Which diagnostic test is considered the gold standard for detecting Johne's disease (paratuberculosis) in small ruminants?
- Fecal ELISA
- Fecal culture for Mycobacterium avium subsp. paratuberculosis (Correct answer)
- Serum AGID test
- PCR of peripheral blood
Correct answer: Fecal culture for Mycobacterium avium subsp. paratuberculosis
Fecal culture for Mycobacterium avium subsp. paratuberculosis is the gold standard, though it is slow (weeks to months) and requires specialized media.
Question 3: Urolithiasis in male small ruminants most commonly causes obstruction at which anatomical site?
- Renal pelvis
- Ureters
- Urethral process (pizzle) (Correct answer)
- Bladder neck
Correct answer: Urethral process (pizzle)
The urethral process (pizzle) at the distal end of the penis is the most common obstruction site due to its narrow lumen in male sheep and goats.
Question 4: Polioencephalomalacia (PEM) in small ruminants is most commonly associated with a deficiency or impaired utilization of which vitamin?
- Vitamin A
- Thiamine (Vitamin B1) (Correct answer)
- Niacin
- Riboflavin
Correct answer: Thiamine (Vitamin B1)
PEM is primarily caused by thiamine deficiency or impaired utilization, leading to necrosis of cerebrocortical gray matter and characteristic neurological signs.
Question 5: Which management strategy best reduces the risk of pregnancy toxemia (twin lamb disease) in late-gestation ewes?
- Increase dietary calcium immediately prepartum
- Provide adequate energy supplementation relative to fetal number (Correct answer)
- Administer prophylactic corticosteroids
- Restrict access to water to reduce edema
Correct answer: Provide adequate energy supplementation relative to fetal number
Adequate energy supplementation adjusted to the number of fetuses being carried prevents the negative energy balance that leads to pregnancy toxemia.
Question 6: Foot rot in sheep caused by Dichelobacter nodosus requires co-infection with which other organism to produce severe disease?
- Fusobacterium necrophorum (Correct answer)
- Treponema denticola
- Actinomyces bovis
- Streptococcus dysgalactiae
Correct answer: Fusobacterium necrophorum
Fusobacterium necrophorum works synergistically with Dichelobacter nodosus to cause the interdigital skin damage and severe tissue destruction seen in virulent footrot.
Question 7: A ewe presents with unilateral facial nerve paralysis, circling, and head pressing 2 weeks after lambing. Cerebrospinal fluid shows elevated protein with mild pleocytosis. Which condition is most likely?
- Polioencephalomalacia
- Listeriosis (circling disease) (Correct answer)
- Scrapie
- Enterotoxemia
Correct answer: Listeriosis (circling disease)
Listeria monocytogenes causes rhombencephalitis ('circling disease') with characteristic brainstem signs including facial nerve palsy, circling, and altered mentation.
ICVA Small Ruminant Herd Health 3
Contagious ecthyma (orf) in sheep and goats is caused by which type of pathogen?