Virology Multiple Choice Questions & Answers (MCQs) focuses on “Polioviruses”.
1. The poliovirus infection is spread through _____________
a) breastfeeding
b) fecal-oral route
c) placental route
d) sexual route
Answer: b
Clarification: The poliovirus infection is spread through the fecal-oral route and the period of incubation is usually 1 – 2 weeks. The systemic symptoms include headache, fever, nausea, vomiting, myalgia.
2. Which of the following complications occur during the infection of poliovirus?
a) Respiratory failure
b) Airways obstruction
c) Kidney failure
d) ANS involvement
Answer: c
Clarification: The complications that occur during the infection of poliovirus are respiratory failure, obstruction of airways, and the involvement of the autonomic nervous system. Kidney failure does not occur due to poliovirus infection.
3. Which of the following is not the laboratory diagnosis of poliovirus?
a) RNA in the fecal sample
b) IgM antibodies in sera
c) IgG antibodies in sera
d) IgA antibodies in sera
Answer: d
Clarification: The laboratory diagnosis of poliovirus includes the demonstration of poliovirus in throat swab or the fecal sample collected in the acute phase of the disease, viral RNA in the fecal sample, and poliovirus IgM antibodies or IgG antibody rise in paired sera.
4. Which of the following causes the paralysis of respiratory and pharyngeal muscles?
a) Bulbar poliomyelitis
b) Asthma
c) Polyradiculitis
d) COPD
Answer: a
Clarification: Bulbar poliomyelitis occurs in about 10% of all patients with paralysis. This may occur as a mixed bulbospinal form and this localization may lead to the involvement of cranial nerves with paralysis of pharyngeal muscles and dysphagia, and respiratory muscles followed by dyspnea.
5. Which of the following is called Guillain-Barre syndrome?
a) Asthma
b) Polyradiculitis
c) Heart failure
d) Paralysis
Answer: b
Clarification: Polyradiculitis is also known as Guillain-Barre syndrome, where the pareses are ascending and symmetrical combined with a variety of sensory disturbances. The cerebrospinal fluid (CSF) shows a high protein content with no or only a slight increase in cell count.
6. Which of the following occurs during the acute stages of poliovirus infection?
a) Encephalitis
b) Post-poliomyelitis syndrome
c) Asthma
d) Ischemic stroke
Answer: a
Clarification: Encephalitis and myocarditis may occur during the acute stages of the poliovirus infection. A post-poliomyelitis syndrome is observed in some 25% of survivors of paralytic poliomyelitis. They may also develop new weakness, pain, and fatigue.
7. The genome of poliovirus is _____________
a) ssDNA
b) ssRNA
c) dsRNA
d) dsDNA
Answer: b
Clarification: The poliovirus consists of single-stranded RNA of positive polarity (mRNA) within a protein shell (capsid) composed of 60 capsomeres. The capsid is built up of four proteins and the virion is naked and has a diameter of 28nm.
8. Polioviruses are ______________
a) resistant to lipid solvents
b) resistant to protein solvents
c) unstable at pH values between 3 – 9
d) infectious for a shorter period in children
Answer: a
Clarification: Polioviruses are resistant to lipid solvents and rather slowly inactivated at room temperature. They are stable at pH values between 3 – 9 and are infectious for a longer period in children than adults.
9. Which of the following is the most widely used vaccine for the prevention of poliomyelitis?
a) OPV
b) MMR
c) COD
d) POR
Answer: a
Clarification: OPV is the most widely used vaccine for the prevention of poliomyelitis. It induces intestinal immunity due to the production of secretory IgA. This is important for the inhibition of virus replication in the gut.
10. VP3 is a capsid protein.
a) True
b) False
Answer: a
Clarification: VP3 is a capsid protein. The capsid is built mainly of four proteins: VP1, VP2, VP3, VP4. The virus replication is initiated by RNA transcription into negative strands to act as templates for new viral RNAs.
11. IPV is an inactivated virus vaccine.
a) True
b) False
Answer: a
Clarification: IPV is an inactivated virus vaccine and was the first vaccine used against poliomyelitis. It is administered parenterally and contains three types of poliovirus inactivated by formaldehyde.
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