TNPSC Animal Husbandry & Veterinary Science (Degree Standard), Code 396 · India · Tamil Nadu Public Service Commission
Original practice questions written to the published syllabus · not past papersVirus structure and replication, the virus families behind the major animal plagues and pet diseases, and how viral infections are diagnosed and vaccinated against.
In the exams: ICAR AICE-JRF core group 06; ICAR AIEEA-PG 13 (Microbiology); China infectious diseases 30
How our questions for TNPSC Animal Husbandry & Veterinary Science, Code 396 spread across the units of Systematic Veterinary Virology. Difficulty: 9 easy, 27 medium, 4 hard.
| Foot-and-mouth disease virus | 6 | |
| PPR virus and rinderpest (history of eradication) | 5 | |
| Capripoxviruses and lumpy skin disease virus | 4 | |
| Rabies virus | 4 | |
| Viral vaccine technology | 4 | |
| Newcastle disease virus | 3 | |
| Marek's disease virus | 3 | |
| African and classical swine fever viruses | 3 | |
| Avian influenza virus | 2 | |
| Infectious bursal disease virus | 2 | |
| Virus structure | 1 | |
| Bluetongue virus | 1 | |
| Equine influenza and equine infectious anaemia viruses | 1 | |
| Viral diagnostics | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Sudden death in unweaned calves during a foot-and-mouth disease outbreak, with grey-white streaks in the myocardium at post-mortem, is called:
A. Tiger heart
Myocarditis in young animals is the main cause of death in foot-and-mouth disease and the streaked myocardium is described as tiger heart. Turkey-egg kidney belongs to classical swine fever, zebra striping to rinderpest and PPR in the large intestine, and sit-fasts to sloughed lumpy skin disease nodules.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Which sample is the first choice for confirming a suspected acute case of foot-and-mouth disease?
A. Fresh vesicular epithelium in buffered transport medium
Vesicular epithelium carries the most virus and supports antigen ELISA, genome detection and typing. A single serum sample cannot distinguish infection from vaccination or tell you the serotype quickly, faeces are a poor sample for this virus, and formalin fixation destroys the material needed for virus detection.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Which test is the reference standard for confirming rabies in an animal?
C. Direct fluorescent antibody test on brain tissue
Diagnosis is made after death on brain tissue, with the direct fluorescent antibody test as the reference, supported by the direct rapid immunohistochemical test and genome detection. Negri bodies are absent in a substantial proportion of true cases, so histology alone cannot exclude rabies, and antibody in an unvaccinated live animal is not a diagnostic test.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
A municipality estimates 40,000 dogs and vaccinates 19,600 in a campaign. By how many dogs does it fall short of a 70% coverage target?
D. 8,400
70% of 40,000 is 28,000 dogs; 28,000 - 19,600 = 8,400. 4,400 comes from using a 60% target, 11,200 from subtracting 19,600 from 30,800 (a 77% target), and 28,000 is the target itself rather than the shortfall. The campaign reached 49% coverage.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Which live Newcastle disease vaccine strains were developed for village poultry where refrigeration is unreliable?
A. Thermostable strains such as V4 and I-2
Thermostable lentogenic strains were selected precisely so that village poultry can be vaccinated without a reliable cold chain, often by mixing with feed or by eye drop. Inactivated oil vaccines cannot be given by spray, and liquid nitrogen storage is a feature of cell-associated Marek's vaccines.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Infectious Marek's disease virus is shed from which site?
C. The feather follicle epithelium, in dander
Fully enveloped infectious virus is produced only in feather follicle epithelium and spreads as dust and dander, which stays infectious in poultry house litter for a long time. Marek's disease virus is not transmitted through the egg, unlike avian leukosis virus.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Cell-associated Marek's disease vaccine must be:
A. Stored in liquid nitrogen and used promptly once thawed and diluted
Live vaccine held inside cells survives only in liquid nitrogen, and once thawed and diluted it must be used quickly, with attention to dilution and needle handling. Ordinary freezer storage destroys the cells, and holding diluted vaccine overnight loses potency.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
A horse tests positive for equine infectious anaemia on a confirmed test. The correct management, subject to national law, is:
D. Permanent isolation or euthanasia, since infection is lifelong with no vaccine or treatment
Infection is lifelong, inapparent carriers still transmit, and there is no internationally used vaccine or treatment, so positive horses are destroyed or kept permanently isolated according to national rules. Expecting treatment or vaccination to resolve the situation is the common error.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
In an outbreak, 480 of 1,200 birds in a shed became sick and 300 of the sick birds died. The attack rate and case fatality rate are:
B. 40% and 62.5%
Attack rate = 480/1,200 = 40%. Case fatality rate = deaths among cases = 300/480 = 62.5%. The option '40% and 25%' uses 300/1,200, which is the mortality rate in the whole shed, not the case fatality rate, and swapping the two figures is the other common error.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
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