Virology Lecture: Viral Infection Pathogenesis and Therapy

What is characteristic of an acute viral infection?

Resolution within days

Which type of infection is confirmed but does not produce obvious symptoms or signs?

Subclinical infection

What characterizes a persistent infection?

Virus is not cleared and remains in specific cells

Which group of viruses cause latent infections?

Herpesviruses Signup and view all the answers

What characterizes virus-induced tumors?

Cause little or no disease after infection Signup and view all the answers

What is common to all viruses that cause tumors?

They have DNA in their virions Signup and view all the answers

What type of infection is associated with herpes viruses?

Latent infections Signup and view all the answers

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

Transforming infections Signup and view all the answers

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

Ultraviolet light exposure Signup and view all the answers

What characterizes an abortive infection?

Synthesis of viral components but no infective virus produced Signup and view all the answers

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

They produce progeny viruses Signup and view all the answers

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

They integrate their genome into the host cell genome Signup and view all the answers

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

Cellular receptor 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?

Chemotherapeutic index Signup and view all the answers

Why is uncoating considered a poor target for antiviral intervention?

It is mediated by cellular enzymes Signup and view all the answers

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

Amantadine and Rimantadine Signup and view all the answers

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

Neuraminidase inhibitors Signup and view all the answers

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

Viruses have their own specific enzymes Signup and view all the answers

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

Live attenuated virus vaccines Signup and view all the answers

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

Long duration of immunity Signup and view all the answers

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

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

How do subunit vaccines present antigens to the immune system?

By presenting only certain proteins of the virus Signup and view all the answers

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

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

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

Disruption of cellular membranes leading to cell lysis Signup and view all the answers

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

Phycodnaviridae Signup and view all the answers

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

Requiring cell lysis Signup and view all the answers

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

Synthesis of viral proteins Signup and view all the answers

What is a key feature of persistent viral infections?

Continuous production of virus by the survival of infected cells Signup and view all the answers

Which type of viral infections typically results in cell death?

Acutely cytopathogenic infections Signup and view all the answers

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

By encoding proteins that trigger apoptosis and then inhibit it Signup and view all the answers