Virology Lecture: Viral Infection Pathogenesis and Therapy
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Questions and Answers

What is characteristic of an acute viral infection?

  • Gradual onset of disease
  • Chronic persistence of the virus
  • Resolution within days (correct)
  • Long duration of symptoms
  • Which type of infection is confirmed but does not produce obvious symptoms or signs?

  • Persistent infection
  • Chronic infection
  • Subclinical infection (correct)
  • Latent infection
  • What characterizes a persistent infection?

  • Virus is not cleared and remains in specific cells (correct)
  • Virus remains in specific cells but symptoms are seen
  • Infection is terminated within days
  • Virus is cleared by the immune response
  • Which group of viruses cause latent infections?

    <p>Herpesviruses</p> Signup and view all the answers

    What characterizes virus-induced tumors?

    <p>Cause little or no disease after infection</p> Signup and view all the answers

    What is common to all viruses that cause tumors?

    <p>They have DNA in their virions</p> Signup and view all the answers

    What type of infection is associated with herpes viruses?

    <p>Latent infections</p> Signup and view all the answers

    Which type of viral infection results in the formation of tumors?

    <p>Transforming infections</p> Signup and view all the answers

    What may lead to the replication of the viral DNA in latent infections?

    <p>Ultraviolet light exposure</p> Signup and view all the answers

    What characterizes an abortive infection?

    <p>Synthesis of viral components but no infective virus produced</p> Signup and view all the answers

    In null viral infections, what happens when cells lack the appropriate receptors for a particular virus?

    <p>They produce progeny viruses</p> Signup and view all the answers

    What is the characteristic of viruses known as oncogenic or tumor viruses?

    <p>They integrate their genome into the host cell genome</p> Signup and view all the answers

    What is the main target of antiviral drugs during the attachment phase of virus replication?

    <p>Cellular receptor</p> Signup and view all the answers

    Which characteristic is used to measure the effectiveness of an antiviral drug compared to its toxicity to host cells?

    <p>Chemotherapeutic index</p> Signup and view all the answers

    Why is uncoating considered a poor target for antiviral intervention?

    <p>It is mediated by cellular enzymes</p> Signup and view all the answers

    Which drugs act by blocking cellular membrane ion channels, preventing endosomal pH decrease and membrane fusion?

    <p>Amantadine and Rimantadine</p> Signup and view all the answers

    Which type of antiviral drugs are specifically mentioned as active against influenza A viruses?

    <p>Neuraminidase inhibitors</p> Signup and view all the answers

    Why are cycles of virus replication involving gene expression inhibition less amenable to chemical intervention?

    <p>Viruses have their own specific enzymes</p> Signup and view all the answers

    Which category of vaccines is known to provide long-term immunity with replicating virus but reduced virulence?

    <p>Live attenuated virus vaccines</p> Signup and view all the answers

    What is a key advantage of subunit vaccines over conventional vaccines?

    <p>Long duration of immunity</p> Signup and view all the answers

    What is the main difference between live attenuated and inactivated virus vaccines in terms of residual virulence?

    <p>Inactivated vaccines have higher residual virulence than live attenuated vaccines.</p> Signup and view all the answers

    How do subunit vaccines present antigens to the immune system?

    <p>By presenting only certain proteins of the virus</p> Signup and view all the answers

    What is the unique feature of apoptosis compared to other forms of cell death?

    <p>The dying cell remains intact and its contents stay within the plasma membrane</p> Signup and view all the answers

    What is the main reason for cell death in acutely cytopathogenic infections?

    <p>Disruption of cellular membranes leading to cell lysis</p> Signup and view all the answers

    Which family of viruses may induce the synthesis of lytic phospholipids leading to cell lysis?

    <p>Phycodnaviridae</p> Signup and view all the answers

    How do most naked viruses and some enveloped viruses release new virions from the infected cell?

    <p>Requiring cell lysis</p> Signup and view all the answers

    Which mechanism is NOT involved in actively inducing cell lysis by viruses?

    <p>Synthesis of viral proteins</p> Signup and view all the answers

    What is a key feature of persistent viral infections?

    <p>Continuous production of virus by the survival of infected cells</p> Signup and view all the answers

    Which type of viral infections typically results in cell death?

    <p>Acutely cytopathogenic infections</p> Signup and view all the answers

    How do some viruses trigger apoptosis in infected cells while inhibiting it during replication?

    <p>By encoding proteins that trigger apoptosis and then inhibit it</p> Signup and view all the answers

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