Antiviral Drugs and Viral Infections Overview

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Questions and Answers

What is the role of neuraminidase inhibitors like oseltamivir and zanamivir?

To inhibit a viral enzyme essential for virus release (correct)

To enhance the immune response against viruses

To facilitate the entry of viruses into host cells

To boost viral replication

Which protein is responsible for binding the HIV virus to its target cell?

Gp41

Integrase

Gp120 (correct)

Protease

What distinguishes nucleoside reverse transcriptase inhibitors (NRTIs) from non-nucleoside reverse transcriptase inhibitors (NNRTIs)?

NNRTIs require activation by phosphorylation

NRTIs require cellular enzymes for activation (correct)

NNRTIs are more effective than NRTIs

NRTIs do not require any cellular activation

Which enzyme is essential for the assembly of new viruses?

Protease Signup and view all the answers

What is the primary function of integrase in viral replication?

To convert viral RNA into DNA Signup and view all the answers

Zidovudine was notable as the first antiviral drug introduced for the treatment of which virus?

HIV Signup and view all the answers

What triggers the activation of nucleoside reverse transcriptase inhibitors?

Phosphorylation by cellular enzymes Signup and view all the answers

What is the targeted cell type for HIV infection?

CD4 T cells Signup and view all the answers

What is the primary mechanism of action for M2 channel inhibitors like Amantadine and Rimantadine?

They prevent viral uncoating after infection. Signup and view all the answers

What is the primary role of pegylated interferons in the immune system?

To enhance the immune system's ability to combat viruses Signup and view all the answers

Which group of patients is at greater risk for severe symptoms of influenza?

Elderly individuals and those with chronic diseases Signup and view all the answers

Which types of cells are activated by interferons?

Natural killer cells, macrophages, and B cells Signup and view all the answers

What types of influenza primarily affect children and the elderly?

Type B affects children while Type A affects the elderly. Signup and view all the answers

What is the main target organ for hepatitis viruses?

Liver Signup and view all the answers

Which of the following diseases can be caused by influenza?

Pneumonia Signup and view all the answers

What is a significant consequence of chronic hepatitis infection?

Development of cirrhosis Signup and view all the answers

How do interferons help combat viral infections?

They prevent viral penetration and inhibit replication. Signup and view all the answers

Which type of interferon is most commonly used in treatment?

Interferon-alpha 2b Signup and view all the answers

Which type of interferon is specifically mentioned as being used for chronic hepatitis B and C?

Interferon-alpha 2b Signup and view all the answers

How do interferons exert their antiviral effects?

Through inhibition of viral penetration and mRNA translation Signup and view all the answers

Which of the following statements about influenza transmission is accurate?

It spreads easily through droplets during coughing and sneezing. Signup and view all the answers

What is the role of interferons in the immune response?

They act as immunomodulators to control viral replication. Signup and view all the answers

What property do some types of interferons possess that aids in managing chronic conditions?

Anti-inflammatory properties Signup and view all the answers

How are interferons typically produced for therapeutic use?

From mammalian tissues or recombinant DNA technology Signup and view all the answers

What is the main reason for utilizing selective action in antiviral therapy?

To prevent toxicity to the patient's own cells Signup and view all the answers

Which of the following enzymes is NOT implicated in viral replication and is, therefore, not a target for antiviral agents?

Ribonuclease Signup and view all the answers

Which process allows a virus to enter and infect a host cell?

Attachment and penetration Signup and view all the answers

What determines the viral tropism of a virus like HIV?

The presence of specific receptors on host cells Signup and view all the answers

What occurs during the uncoating of a virus?

Release of viral RNA or DNA Signup and view all the answers

Which enzyme is responsible for the integration of viral genetic material into the host cell's DNA?

Integrase Signup and view all the answers

Which of the following is NOT a phase in the life cycle of a virus?

Metabolism Signup and view all the answers

What is the primary characteristic of viral tropism?

The preference of a virus for specific cell types Signup and view all the answers

What is required for the activation of Acyclovir in infected cells?

Thymidine kinase Signup and view all the answers

In which type of cells does the conversion of Acyclovir occur?

Infected cells Signup and view all the answers

Which of the following drugs is classified as a neuraminidase inhibitor?

Zanamivir Signup and view all the answers

What role does neuraminidase play in the influenza virus life cycle?

Helps release new viruses into circulation Signup and view all the answers

Amantadine and Rimantadine are used to treat which type of influenza?

Influenza A only Signup and view all the answers

What is the common symptom of influenza not typically mentioned?

Skin rash Signup and view all the answers

Which protein is essential for the attachment of the influenza virus to host cells?

Hemagglutinin Signup and view all the answers

What is the main therapeutic action of neuraminidase inhibitors?

Prevent viral replication and transmission Signup and view all the answers

What is the role of enfuvirtide in HIV treatment?

It prevents the virus from binding to host cells. Signup and view all the answers

Which step does amantadine affect in the viral replication process?

It blocks the uncoating process of the virus. Signup and view all the answers

How do nucleoside reverse transcriptase inhibitors (NRTIs) function?

They target an enzyme essential for viral replication. Signup and view all the answers

What is the primary function of interferon in treating viral infections?

To prevent the penetration of the virus into host cells. Signup and view all the answers

Which component is primarily synthesized during the viral replication process?

Viral nucleic acid. Signup and view all the answers

What role do protease inhibitors (PIs) play in HIV treatment?

They inhibit an enzyme called CYP3A. Signup and view all the answers

What happens to viral nucleic acid after the uncoating process?

It integrates with the host nucleic acid. Signup and view all the answers

Which antiviral strategy is commonly used in treating both HIV and hepatitis C?

Interferon treatments. Signup and view all the answers

Study Notes

Antiviral Drugs

Antiviral drugs target viral enzymes and structures vital for replication.
They target specific viral proteins in the replication process.
Antiviral drugs are available for viruses causing significant morbidity and mortality.
Morbidity refers to the suffering from diseases.
Mortality is the deaths caused by diseases.

Overview of Viral Infections

Viruses infect various organs, including the liver, brain, and immune system.
The targeted organ varies depending on the virus.
Examples listed include encephalitis, meningitis, common cold, herpes simplex, respiratory infections, hepatitis, skin infections, cardiovascular, eye infections, and sexually transmitted diseases.

Learning Objectives

Reasons for the difficulty of antiviral drug development.
Targets for antiviral drugs.
Mechanism of antiviral therapy against herpes viruses.
HAART treatment for HIV infections.
Combination therapy benefits for HIV infections.
Neuraminidase inhibitors used in influenza infections.
Interferons' role in hepatitis C therapy.

Targets for Antiviral Agents

DNA dependent DNA polymerase
RNA dependent RNA polymerase
RNA dependent DNA polymerase
Integrase
Protease
Neuraminidase

Attachment and Penetration of Virus

Viruses attach to specific host cells.
Entry into the host cell through receptor binding.
Viral fusion with the host membrane.

Synthesis of New Viral Components

Virus directs host cell machinery for protein synthesis.
Viral RNA or DNA directs protein synthesis.
Production and assembly of new viral components.

Assembly of Components into New Virus

Assembly of the viral components into new viruses.

Release of the Virus from Host Cell

Release of newly formed viruses from the host cell.

Problems in Developing Antiviral Agents

High diversity among viruses.
Rapid replication and mutation, leading to antigen changes.
Intracellular reproduction of viruses.
Selectivity requirement, avoiding harm to host cells.
Toxicity -Viral obligate intracellular reproduction depends on host cell functions.

Antiretroviral Drugs (ART)

Nucleoside reverse transcriptase inhibitors (NRTIs)
Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
Protease inhibitors (PIs)
Integrase inhibitors
Chemokine receptor antagonists
HIV fusion inhibitors

Highly Active Antiretroviral Therapy (HAART)

Combination of at least 3 antiretroviral drugs.
Suppresses HIV replication and viral load.
Reduces resistance development to ARV.
Restores the immune function (CD4 count).
Reduces mortality and morbidity.
Improves quality of life.
Prevents HIV transmission.

Herpes Simplex Viruses (HSV)

Two major types: HSV-1 (oral herpes) and HSV-2 (genital herpes).
Similar structures, different sites of infection.
Transmission via close contact, saliva, or sexual contact.

Antiviral Therapy for Herpes Viruses

Acyclovir or its analogues are used.
Competitiveness for guanosine triphosphate (GTP) for incorporation into viral DNA.
Inhibition of DNA polymerase.
Effective for herpes simplex and varicella-zoster viruses.

Anti-Influenza Drugs

Neuraminidase inhibitors (prevent viral release)
Amantadine and rimantadine (inhibit viral uncoating)
Targeting influenza A&B virus.

Interferons

Cytokines that act on viral replication.
Type of interferons (alpha, beta, gamma) are important in antiviral action.
Used to treat chronic B and C hepatitis.
Pegylated forms are used for better efficacy and longer duration.

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Description

This quiz focuses on antiviral drugs, their mechanisms, and the types of viral infections they target. It covers the challenges in developing antiviral medications and explores specific therapies for diseases like HIV and herpes. Test your knowledge on the impact of viral infections on various organs.