ICAR AICE-JRF/SRF (PhD) · India · NTA for ICAR
Original practice questions written to the published syllabus · not past papersThe bacteria and fungi that cause disease in animals, genus by genus: what they are, where they live, what they cause and how they are identified.
In the exams: ICAR AICE-JRF core group 06; ICAR AIEEA-PG 13 (Microbiology); China preventive paper
ICAR AICE-JRF/SRF (PhD) — core group 06 (Microbiology)
Deeper genus-level detail: virulence factors (anthrax plasmids, leukotoxin, epsilon and beta toxins, Shiga toxin 2e, fimbrial adhesins), mycobacterial growth requirements (pyruvate, mycobactin), the interpretation of comparative tuberculin and interferon-gamma tests, rough versus smooth Brucella serology, and mycotoxins and their target organs.
How our questions for ICAR AICE-JRF/SRF spread across the units of Systematic Veterinary Bacteriology & Mycology. Difficulty: 12 easy, 28 medium, 6 hard.
| Aspergillus and Candida | 5 | |
| Mycobacterium: tuberculosis and Johne's disease | 4 | |
| Brucella | 4 | |
| Bacillus anthracis | 3 | |
| Clostridium | 3 | |
| Salmonella | 3 | |
| Escherichia coli | 3 | |
| Leptospira | 3 | |
| Mycoplasma | 3 | |
| Rickettsia and Chlamydia | 3 | |
| Staphylococcus | 2 | |
| Streptococcus | 2 | |
| Pasteurella and Mannheimia | 2 | |
| Listeria | 2 | |
| Burkholderia mallei (glanders) | 2 | |
| Dermatophytes | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Which single bench test most quickly separates a Gram-positive coccus isolated from mastitic milk into Staphylococcus or Streptococcus?
D. Catalase test: staphylococci bubble, streptococci do not
Staphylococci are catalase positive and release bubbles from hydrogen peroxide; streptococci are catalase negative. Coagulase is used after catalase, to split staphylococci into coagulase-positive and coagulase-negative groups, and streptococci do not clot plasma. Oxidase and indole are tests for Gram-negative rods.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
On Edwards medium a bovine mastitis streptococcus grows as dark colonies because it hydrolyses aesculin. Which species is most likely?
D. Streptococcus uberis, an environmental pathogen
S. uberis hydrolyses aesculin and gives dark colonies on Edwards medium; S. agalactiae and S. dysgalactiae are aesculin negative. S. equi is not a bovine mastitis pathogen.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Why is Clostridium perfringens type C enteritis mainly a disease of newborn piglets, calves and lambs?
D. Colostral trypsin inhibitors protect the trypsin-sensitive beta toxin
Beta toxin is destroyed by trypsin. Colostrum contains trypsin inhibitors and neonatal pancreatic secretion is low, so the toxin survives in the neonatal gut. Epsilon toxin is the type D toxin and is activated, not destroyed, by trypsin.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Mycobacteria resist decolourisation by acid-alcohol in the Ziehl-Neelsen stain because their cell wall is rich in:
C. Mycolic acids
Long-chain mycolic acids make the wall waxy, so carbol fuchsin is retained after acid-alcohol and the bacilli stay red. Teichoic acids are features of ordinary Gram-positive walls, and lipopolysaccharide is the outer membrane of Gram-negative bacteria; neither confers acid-fastness.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Fowl cholera of chickens, turkeys and ducks is caused by:
A. Pasteurella multocida
Fowl cholera is a P. multocida infection causing acute septicaemia or chronic localised infection such as swollen wattles. Salmonella Gallinarum causes fowl typhoid, and Avibacterium paragallinarum causes infectious coryza; the similar names are the usual trap.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Which Salmonella serovar is host-adapted to cattle and causes abortion and long-term carriers in adult cows?
C. Dublin
S. Dublin is adapted to cattle and causes enteritis, septicaemia, abortion and persistent carriage. Choleraesuis is adapted to pigs, Abortusovis to sheep, and Pullorum to poultry.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Which Salmonella serovar can colonise the reproductive tract of laying hens and contaminate the contents of eggs without making the hens ill?
D. Enteritidis
S. Enteritidis infects the ovary and oviduct and contaminates egg contents while hens stay healthy, which makes it a major food-borne zoonosis. S. Gallinarum causes fowl typhoid, a severe disease of the birds themselves.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
A goat dies after showing circling. Which sample and lesion best confirm encephalitic listeriosis?
C. Brainstem, showing microabscesses and perivascular cuffing
Listeria causes rhombencephalitis, and the brainstem (medulla and pons) shows microabscesses with perivascular cuffing; it is also the sample for culture. Laminar cortical necrosis is polioencephalomalacia, and a pulpy kidney with glycosuria is type D enterotoxaemia.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
Heartwater of ruminants, spread by Amblyomma ticks, is caused by:
A. Ehrlichia ruminantium
Heartwater (cowdriosis) is caused by E. ruminantium, formerly Cowdria ruminantium, and causes fever, nervous signs and hydropericardium. It is diagnosed by finding the organism in capillary endothelium in brain crush smears. A. marginale causes anaplasmosis.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
White, raised plaques with a 'Turkish towel' appearance on the crop mucosa of poultry after prolonged antibiotic treatment indicate:
A. Candidiasis (crop mycosis)
Candida albicans overgrows when antimicrobials disturb the normal flora and produces thick white plaques on the crop. Aspergillus affects the respiratory tract; trichomoniasis and diphtheritic pox produce caseous lesions mainly in the mouth and upper digestive tract and are not linked to antibiotic use.
Further reading: Quinn et al., Veterinary Microbiology and Microbial Disease; WOAH Terrestrial Manual
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