Deck 13: Viral Infection

Question 1

Viral infections that last the lifetime of the host are referred to as _____ infections.

A)Acute
B)Latent
C)Persistent
D)Immunosuppressive
E)Chronic

Answer 1

Persistent

Question 2

An example of a virus that does not use host neurons for the establishment of latency is

A)Herpes simplex virus type 2
B)Varicella-zoster virus
C)Hepatitis C virus
D) Herpes simplex virus type 1

Answer 2

Hepatitis C virus

Question 3

Which of the following is not an example of a virus associated with persistent infections of humans?

A)Epstein-Barr virus
B)Human immunodeficiency virus
C)Influenza virus
D)Hepatitis C virus
E)Herpes simplex virus type 1

Answer 3

Influenza virus

Question 4

Indicate which of the following statements is false.

A)Human immunodeficiency virus (HIV) can be transferred in utero
B)Herpes viruses sometimes cause Koplik's spots on mucosal epithelium
C)The transmission rate of rubella from pregnant women to the fetus is more than 80% during the first trimester
D)Viruses disseminating from the blood to other replication sites are using the hematogenous route of transmission

Question 5

Which of the following is a mismatched pair in reference to viral transmission?

A)HIV: in utero
B)Rabies: zoonotic disease
C)Iatrogenic: sexually transmitted
D)Rhinovirus: aerosol
E)Herpes simplex virus: semen

Question 6

Which of the following is not a characteristic of latent viral infections?

A)Survival of intact viral genomes in infected host cells
B)Non-productive infection and few virions
C)Reactivation can occur years after initial infection
D)Absence of or reduction in host immune responses
E)Major changes in virion structure due to the acquisition of new viral genes

Question 7

Which of the following uses host intestinal proteases to be converted into infectious viral particles?

A)Rhinovirus
B)Norwalk virus
C)Poliovirus
D)Reovirus
E)Adenovirus

Question 8

Mr.Johnson has an immunodeficiency disease called X-linked agammaglobulinemia owing to a genetic defect in a gene called Bruton's tyrosine kinase (Btk),which is required for B cell development.He lacks B cells and is therefore unable to produce antibodies.He receives regular injections of gammaglobulin to ensure he has protective immunity against microbial diseases.This is an example of

A)Active immunity
B)Attenuated immunity
C)Subunit vaccination
D)Passive immunity
E)Inactivated immunity

Question 9

In reference to cytotoxic T lymphocyte (CTL)escape mutants,which of the following statements is correct?

A)If immunodominant peptides mutate, the host's cytotoxic T lymphocytes are no longer able to respond
B)Escape mutants are associated more commonly with DNA viruses than with RNA viruses
C)If escape mutants occur late in an infection, a persistent infection occurs
D)Viruses escaping cytotoxic T lymphocyte detection are usually cleared effectively by host antibody responses

Question 10

The varicella-zoster virus establishes latency in the _____,and if reactivated causes the development of _____.

A)Conjunctiva; seed warts
B)Respiratory tract; pneumonia
C)Central nervous system; Negri bodies
D)Sensory ganglia; shingles

Question 11

Papillomavirus,which causes skin warts,is able to subvert cytotoxic T lymphocytes (CTL)responses by

A)Infecting tissues that are sequestered from the immune system
B)By inducing CTL death through Fas
C)Establishing latency in nerve ganglia
D)Suppressing the production of immunodominant peptides
E)Changing virion structure through antigenic variation

Question 12

All of the following cause skin rashes in humans except

A)Rubella virus
B)Measles virus
C)Parvovirus
D)Hepatitis C virus
E)Varicella-zoster virus

Question 13

Which of the following is true about persistent viral infections?

A)Virions continue to be produced for months
B)Such an infection can become chronic
C)Such an infection can remain for a lifetime
D)A persistent viral infection can occur if the virus mutates to become an escape mutant
E)All of the choices are true

Question 14

Virus that use the digestive tract as a site of entry can become systemic by

A)Entering the blood and lymph through abrasions of the intestinal epithelium
B)Direct transfer into the intestinal lymph system
C)Using M cells to enter the blood and lymph
D)Degrading cell membranes and entry into the bloodstream

Question 15

Which of the following is not a requirement of an effective vaccine?

A)The components of the vaccine should induce protective immune responses
B)The host should mount a memory response that has the capacity to respond if the pathogen is encountered at a later time
C)The vaccine should induce only mild disease
D)The vaccine should be biologically stable
E)The cost to produce and administer the vaccine should be minimized to promote effective use in target populations

Question 16

When changes in virion structure occur as a result of major genetic changes,this is called

A)Antigenic drift
B)Mutational shift
C)Conformational mutagenesis
D)Antigenic shift

Question 17

Active viremia describes

A)Replication of viruses and the initial site of entry
B)Replication of viruses in secondary organs
C)Replication of viruses in the blood
D)Replication of viruses in the next host after viral transmission

Question 18

Which of the following explains why some acute viral infections are asymptomatic in individuals exposed to a virus for the first time?

A)Innate immune defenses restrict the spread and severity of viral infections
B)They have a short incubation period
C)The adaptive immune response is deployed quickly
D)Acute viruses become avirulent soon after infection

Question 19

Which of the following is a mismatched pair in reference to viral entry points and dissemination?

A)Skin: rabies virus
B)Respiratory tract; herpes simplex virus
C)Nervous system: poliovirus
D)Urogenital system: papillomavirus
E)Digestive tract: adenovirus

Question 20

What are the cause of over 50% of the common colds we acquire?

A)Coronaviruses
B)Cytomegaloviruses
C)Arena viruses
D)Coxsackie virus
E)Rhinoviruses

Question 21

Rhinovirus and influenza viruses often cause reinfection in people that have already been a host to the disease.How is this possible?

A)Antigenic variation
B)Antigenic drift
C)Antigenic shift
D)All of the above

Question 22

The digestive tract is a common site of entry for many viruses,even though it contains stomach acid,bile,and phagocytic cells,which create a hostile environment.Which of the following viruses require entry through the digestive tract for infection?

A)Reovirus
B)Adenovirus
C)Rhinovirus
D)Papillomavirus

Question 23

Explain why an individual who has had a prior infection with a rhinovirus is quite likely to experience another episode of rhinovirus infection at a later date.Why do we not immunize against rhinovirus?

Question 24

An oncogenic virus is one that

A)Stimulates ongoing immunity and memory responses
B)Integrates into the genome of the host cell it infects
C)Enters the body through the genitourinary tract
D)Has been eradicated and is no longer used in immunization programs
E)Can induce cancer in animals

Question 25

Many viruses are able to be reactivated many years after initial entrance into a host.An example of this is the varicella-zoster virus and shingles.This is an example of a(n)

A)Acute infection
B)Persistent infection
C)Latent infection
D)Slow infection

Question 26

Why is vaccination the most promising approach to the control of viral epidemics? Describe the three classes of viral vaccine administered to humans and provide examples of each.

Question 27

The duration of a rhinovirus infection and an influenza infection is usually only limited to 4-5 days.What type of viral infection does this represent?

A)Acute infection
B)Persistent infection
C)Latent infection
D)Slow infection

Question 28

What is virulence and what factors have an effect on the virulence of viral infections? Explain why host susceptibility is such an important consideration in viral virulence.