ICAR AIEEA (PG): Master's entrance, Veterinary Science and Animal Sciences · India · NTA for ICAR
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
ICAR AIEEA (PG) — Veterinary Science (code 13), Microbiology
Family, genus and genome type of each major virus; serotypes (seven for FMD, 24 classical for bluetongue, one for PPR and ND); key proteins (VP1, VP2, VP7, HA/NA, HN/F, G); egg inoculation routes; classical tests (HI, AGID/Coggins, FAT for rabies, NSP ELISA); vaccine strains and types.
How our questions for ICAR AIEEA spread across the units of Systematic Veterinary Virology. Difficulty: 42 easy, 32 medium, 30 hard.
| Viral diagnostics | 11 | |
| Viral vaccine technology | 10 | |
| African and classical swine fever viruses | 8 | |
| PPR virus and rinderpest (history of eradication) | 7 | |
| Rabies virus | 7 | |
| Bluetongue virus | 7 | |
| Infectious bursal disease virus | 7 | |
| Virus structure | 6 | |
| Foot-and-mouth disease virus | 6 | |
| Avian influenza virus | 6 | |
| Marek's disease virus | 6 | |
| Equine influenza and equine infectious anaemia viruses | 6 | |
| Virus replication | 5 | |
| Capripoxviruses and lumpy skin disease virus | 5 | |
| Newcastle disease virus | 5 | |
| Canine parvovirus and canine distemper virus | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Lumpy skin disease virus is spread mainly by:
B. Mechanical transmission by biting flies, mosquitoes and ticks
Transmission is chiefly mechanical on the mouthparts of biting arthropods, which explains the seasonality and the jumps between distant herds; direct contact plays a smaller part and virus is also present in semen. Aerosol spread and feed-borne spread are not the main routes, and there is no established biological cycle in sandflies.
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
Serological testing before international pet travel commonly requires a rabies neutralising antibody titre of at least:
C. 0.5 IU per mL
Many importing countries set 0.5 IU per mL, measured by a fluorescent antibody virus neutralisation or rapid fluorescent focus inhibition test, as evidence of an adequate response to vaccination; the exact requirement and the waiting period vary by country. The other figures are order-of-magnitude slips.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Virulence of Newcastle disease virus is determined chiefly by:
C. The amino acid sequence at the fusion protein precursor cleavage site
Virulent strains carry several basic amino acids at the F0 cleavage site with phenylalanine at position 117, so the precursor is cleaved by proteases present in many tissues; avirulent strains need trypsin-like enzymes restricted to the respiratory and intestinal tracts. Influenza-style HA subtypes do not exist in this virus.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Infectious bursal disease virus principally destroys:
B. Immature IgM-bearing B lymphocytes in the bursa of Fabricius
The virus targets dividing IgM-positive B cells in the bursa, which is why the lasting consequence is antibody-mediated immunosuppression. T cells in the thymus are the target of Marek's disease virus transformation, a different poultry disease.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Which vaccine approach removes the problem of timing live infectious bursal disease vaccination around maternal antibody?
A. Turkey herpesvirus-vectored VP2 or immune-complex vaccine, given in ovo or at hatch
A vectored vaccine delivers the protective VP2 antigen inside a carrier virus that maternal antibody to the bursal disease virus does not neutralise, and immune-complex vaccines release antigen as antibody wanes; both can be applied in ovo or at hatch. Inactivated vaccine at hatch does not protect chicks in time, and doubling a live dose does not overcome neutralisation reliably.
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
Equine infectious anaemia virus is transmitted mainly by:
D. Mechanical transfer of blood by large biting flies and by contaminated needles
Tabanid and stomoxys-type flies carry infected blood on their mouthparts, and shared needles, dental instruments or blood products do the same; the virus does not replicate in the insect. Aerosol and feed-borne spread are not routes for this lentivirus.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
DIVA testing depends on:
C. A vaccine lacking (or carrying) a marker antigen, paired with a test for antibody to it
The principle is a difference in antigenic content between vaccine and field virus, detected by a companion serological test: antibody to foot-and-mouth disease non-structural proteins, or to the classical swine fever Erns protein with an E2 subunit vaccine. Sensitivity of a genome test has nothing to do with it.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
In a field trial, 240 of 800 unvaccinated animals and 36 of 1,200 vaccinated animals developed disease. What is the vaccine efficacy?
B. 90%
Attack rate unvaccinated = 240/800 = 0.30; attack rate vaccinated = 36/1,200 = 0.03. Efficacy = (0.30 - 0.03)/0.30 = 0.90, that is 90%. Answering 27% subtracts the attack rates without dividing by the unvaccinated rate, and 85% comes from comparing raw case numbers (1 - 36/240) while ignoring the different group sizes; 15% is that raw ratio itself.
Further reading: Standard veterinary virology texts and WOAH Terrestrial Manual disease chapters
Ten here, 104 in the app. The Laisha app has every practice question we have written to ICAR AIEEA in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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