BCSE BCSE - Basic and Clinical Sciences Examination Veterinary Microbiology and Infectious Diseases Questions and Answers 1 — Questions and Answers
Question 1: Which bacterial pathogen is the most common cause of leptospirosis in dogs in the United States?
- Leptospira interrogans serovars Canicola and Icterohaemorrhagiae (Correct answer)
- Brucella canis
- Borrelia burgdorferi
- Ehrlichia canis
Correct answer: Leptospira interrogans serovars Canicola and Icterohaemorrhagiae
Leptospira interrogans serovars Canicola and Icterohaemorrhagiae are the serovars most frequently associated with leptospirosis in US dogs.
Question 2: Parvovirus type 2 in dogs primarily damages which tissue to cause hemorrhagic enteritis?
- Intestinal crypt epithelium (Correct answer)
- Colonic goblet cells
- Gastric parietal cells
- Duodenal Brunner's glands
Correct answer: Intestinal crypt epithelium
Canine parvovirus-2 targets rapidly dividing intestinal crypt epithelial cells, destroying the mucosal renewal mechanism and leading to hemorrhagic enteritis.
Question 3: Which organism causes 'Potomac horse fever' (equine monocytic ehrlichiosis) in the United States?
- Neorickettsia risticii (Correct answer)
- Anaplasma phagocytophilum
- Ehrlichia ruminantium
- Rickettsia rickettsii
Correct answer: Neorickettsia risticii
Neorickettsia risticii (formerly Ehrlichia risticii) is the causative agent of Potomac horse fever, transmitted via ingestion of infected aquatic insects.
Question 4: The Gram stain appearance of Clostridium perfringens from a culture is best described as:
- Large Gram-positive rods with subterminal spores (Correct answer)
- Gram-negative diplococci
- Gram-positive cocci in clusters
- Slender Gram-negative rods with polar flagella
Correct answer: Large Gram-positive rods with subterminal spores
Clostridium perfringens appears as large, boxcar-shaped Gram-positive rods, typically with subterminal (rarely terminal) endospores.
Question 5: Which test is considered the 'gold standard' for diagnosis of Johne's disease (paratuberculosis) in cattle?
- Fecal culture for Mycobacterium avium subsp. paratuberculosis (Correct answer)
- ELISA serology
- Intradermal Johnin test
- Complete blood count
Correct answer: Fecal culture for Mycobacterium avium subsp. paratuberculosis
Fecal culture for Mycobacterium avium subsp. paratuberculosis remains the gold standard, though it requires 8–16 weeks of incubation.
Question 6: Feline infectious peritonitis (FIP) is caused by a mutated form of which virus?
- Feline enteric coronavirus (Correct answer)
- Feline herpesvirus-1
- Feline calicivirus
- Feline leukemia virus
Correct answer: Feline enteric coronavirus
FIP arises when feline enteric coronavirus mutates to a highly pathogenic biotype that infects and replicates within macrophages, causing systemic vasculitis.
BCSE BCSE - Basic and Clinical Sciences Examination Veterinary Microbiology and Infectious Diseases Questions and Answers 1
Which bacterial pathogen is the most common cause of leptospirosis in dogs in the United States?