SOKOINE UNIVERSITY OF AGRICULTURE
College of Veterinary Medicine and Biomedical Sciences
VM 235: Veterinary Virology CAT 2 Total Marks: 100 Date: 12th January 2023 Time: 60 minutes
General instructions: Answer all THREE questions. One mark will be deducted for any wrong answer while the rubbed and cancelled answers will not be marked.
1. Select the best answer among the alternative statements given for each question and circle it (Each 2 marks, Total 60 marks).
i. Which viruses appear to be hypermutable?
A) DNA viruses
B) ‘Emerging’ viruses
C) Influenza and HIV
D) RNA viruses
ii. Which of the following are necessary for viral reassortment to occur?
A) a circular viral genome
B) a segmented viral genome
C) an ambisense viral genome
D) provirus
iii. The following routes that can serve for both entry into the host and shedding of the virus to the environment
A) Mouth, anus and conjunctiva
B) Anus, urogenital and respiratory tract
C) Mouth, urogenital tract and conjunctiva
D) Mouth, skin and respiratory tract
E) Skin, urogenital and respiratory tract
iv. In phenotypic mixing, two virus particles share
A) Envelope
B) Coat proteins
C) Genetic material
D) Nucleocapsids
E) Segments
v. The following are DNA viruses (circle all that apply)
A) Herpesviruses
B) Orthomyxoviruses
C) Enteroviruses
D) Hepadnaviruses
E) Parvoviruses
vi. The following are RNA viruses (circle all that apply)
A) Picornaviruses
B) Adenoviruses
C) Papillomaviruses
D) Rhabdoviruses
E) Rotaviruses
vii. When a virus enters a cell but does not replicate immediately, the situation is called
A) lysogeny B) latent C) symbiosis
D) synergism E) incubation F) lytic
viii. Inclusion bodies of rabies virus are called:
A) intracytoplasmic B) intranuclear
C) Negri bodies C) both (a) and (b)
D) none of the above
ix. Mutations in viral genomes… (circle all that apply)
A) can cause phenotype changes in the virus
B) can be missense mutations
C) occur more frequently in RNA viruses
D) can be nonsense mutations
E) can be increased by the presence of certain chemicals
x. The vast majority of viruses encountered by the host…
A) can be mitigated by the host immune system
B) are responsible for about 90% of all morbidity and mortality
C) are lethal
D) have the ability to overcome the host immune system
E) make human and animals sick
xi. The following is true of rabies virus (circle all that apply)
A) The majority of cases worldwide result from bat bites
B) Infection may be prevented by active and passive immunisation
C) Rabies vaccine is a live attenuated vaccine
D) The animal reservoir differs from country to country
E) May be diagnosed by serology
xii. Rabies exposure (circle all that apply)
A) is excluded if the biting animal remains well after observation for 10 days
B) in the recent past must be evident from bit wounds or from the patient’s history
C) from contact with bats should be considered in cases of ascending paralysis
D) if it occurred more than 90 days ago, cannot result from the disease
E) from wild animals may be preventable in some countries by use of baits containing an oral vaccine
xiii. Influenza A Virus (circle all that apply)
A) May undergo antigenic shift and antigenic drift
B) May cause pandemics
C) Respond to rimantidine
D) Respond to neuraminidase inhibitors
E) Vaccination confers lifelong protection
xiv. The following antiviral agents is active against the following virus replication step (circle all that apply)
A) Amantadine and uncoating
B) Maraviroc and protease inhibitors
C) Acyclovir and nucleic acid synthesis
D) Enfuvirtide and fusion
xv. HIV may respond to (circle all that apply)
A) Nucleoside analogues
B) Protease inhibitors
C) Neuraminidase inhibitors
D) Reverse transcriptase inhibitors
E) Acyclovir
xvi. Agents that interfere with viral multiplication include (circle all that apply)
A) Amphoteriein B
B) Amantadine
C) Metronidazole
D) Zidovudine
E) Ribavirin
xvii. During the incubation period of HIV infection, there is
A) Little HIV replication
B) HIV is mainly integrated into the genome of long-lived cell populations
C) High turnover of CD4 cells
D) The viral load has a direct bearing on the prognosis
E) Little antibody against the HIV envelope
xviii. Edward Jenner began inoculating humans with material from __________ lesions.
A) Smallpox
B) Avianpox
C) Cowpox
D) Chickenpox
E) Adenovirus
xix. The viruses in an attenuated vaccine
A) have no genome
B) have no capsid
C) continue to replicate
D) are usually larger than bacteria
E) is altered with chemicals
xx. Which of the following viruses belong to family Flaviviridae?
A) Dengue virus
B) Yellow fever virus
C) Zika virus
D) West Nile virus
E) All of these
xxi. Enzyme neuraminidase is carried by which of the following viruses?
A) Human immunodeficiency virus
B) Epstein-Barr virus
C) Influenza virus
D) Adenovirus
xxii. Which one is not useful in the treatment of viruses
A) Acyclovir
B) Interferon
C) Penicillin
D) Antibodies
xxiii. The infected cells continue to reproduce themselves as well as the virus, and the mature virions are extruded from the cell surface continuously over a long period of time. This type of release mechanism is called a
A) productive infection
B) inductive infection
C) resultant infection
D) all of these
xxiv. Intracellular structures formed during many viral infections, called __________, which can directly disrupt cell structure.
A) prokaryotes
B) chromosomal disruptions
C) inclusion bodies
D) cytocidal bodies
xxv. The disease(s) caused by genus Orthopoxvirus is/are
A) Vaccinia
B) Smallpox
C) Cowpox
D) All of these
xxvi. Which of the following genera is included in the family Picornaviridae?
A) Enterovirus
B) Rhinovirus
C) Hepatovirus
D) All of these
xxvii. Which of the following nucleic acid is present in hepatitis B virus?
A) dsDNA
B) ssRNA
C) ssDNA
D) dsRNA
xxviii. Influenza virus undergoes antigenic shift resulting in major antigenic changes by which of the following mechanisms?
A) Somatic recombination of heavy and light chains
B) Expression of several different capsule types
C) Changing the receptor binding canyon that docks with the host receptor
D) Reassortment of RNA segments from different influenza viruses
xxix. Which of the following virus is transmitted by the respiratory route?
A) Rhinovirus
B) Coronavirus
C) Measles virus
D) Influenza virus
E) All of these
xxx. The species of animals which is most susceptible to rabies infection is
A) dog
B) cat
C) fowl
D) cow
E) goat
2. Indicate whether the following statements are TRUE or FALSE (Each 2 marks, Total 22 marks).
i. In most cases we can be infected with viruses, become sick for about a week and recover without any treatment.……………………………………………………………………………….……………………
ii. It is not in the interest of the viruses to severely harm or kill the host, but all the viruses kill the host ……
iii. For ensuring a successful viral infection, the local host immune systems must be present or at least initially active………………………………………………………………………………………………..
iv. For a viral disease to develop, the virus must implant and replicate at the portal of entry, spread and replicate within the host target organs and finally shed out to the environment………..……………………
v. Lytic and latent infections are productive types of viral infections……………………..…………………..
vi. Persistence and transforming infections are nonproductive types of infections……………………………..
vii. Mutations are random events and the vast majority of mutations lead to the loss of gene function…..……
viii. Antibodies to the HA and NA proteins of influenza viruses play a role in protection from infection……
ix. Amantidine and rimantidine are used for prophylaxis of influenza A virus…………………………….…..
x. If a pseudotype virus were made in which a retrovirus genome in a retrovirus capsid was packaged in a rhabdovirus envelope, the PROGENY virus would have the host range of the rhabdovirus………………
xi. If two viruses show complementation, this means that their genetic material (RNA or DNA according to which viruses are involved) has undergone some form of recombination………………………….………
3. Select the answer among the alternatives given in list B that best matches with the statement in list A, then write the letter of the correct response in spaces provided in list A (Each 2 marks, Total 18 marks)
| LIST A | LIST B |
| i. Viral infections Adenovirus that produces a progeny virus via cell lysis and the virus genome replication cannot persist……..……………………………
ii. Viral infections of relatively short duration with rapid recovery……………… iii. Viral infections by HIV where the virus gradually increase in number over a very long period of time during which no significant symptoms are seen…… iv. Viral infections by HIV, Hepatitis B and C virus where the virus can be demonstrated in the body for a long period either with or without cell death and the disease may be present or absent.………………………………..…… v. Viral infections by herpesvirus and HIV where the virus remains in equilibrium with the host for long periods of time before symptoms again appear, but the actual viruses cannot be detected until reactivation of the disease occurs…………………………………………………………………. vi. Viral infections where the virus causes the cell to underdo immortalization and inherit the genetic material to produce tumors…………………………… vii. The process by which segmented viruses swap their gene segments……… viii. A form of interaction between two viruses each of which holds its own unique genetic material but share coat proteins………………………..……… ix. The H1N1/09 influenza virus or “swine flu” is believed to have developed after co-infection of pigs with multiple influenza virus strains, resulting in the development of a very divergent viral subtype in a process known as…… |
A. Acute viral infections
B. Slow viral infections C. Latent viral infections D. Chronic viral infections E. Lysogenic viral infections F. Lytic viral infections G. Transforming viral infections H. Recombination I. Reassortment J. Genetic mixing K. Phenotypic mixing L. Antigenic drift M. Antigenic shift
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