Antivirals (Exam V) Flashcards
Are viruses alive or dead?
What are they?
- Neither (can be active or inactive)
- Obligate intracellular parasites
What two components do all viruses have?
- Capsid (external coating)
- Core of nucleic acids
What does the statement “most viruses are self-limiting” mean?
- They are dealt with by the body’s innate immune defense mechanisms and require no antiviral medication.
What are the two overarching categories of viruses?
- DNA Viruses
- RNA Viruses
What sub-category of RNA viruses is unique? How are they different from other viruses?
- Retroviruses
- Reverse Transcriptase mechanism (RNA → DNA vs DNA → RNA → proteins)
What type of anti-viral therapy is non-targeted?
Interferon
What is a viral capsid?
How would a nucleocapsid differ from this?
- Shell surrounding nucleic acids
- Nucleocapsids are capsid & nucleic acid together.
What is a viral envelope usually composed of?
- Modified piece of a host cell membrane
Naked viruses consist only of a ____________.
nucleocapsid
What component of a virus allows “docking” on host cells?
spikes
How does a virion differ from a virus?
- Virion = Fully formed virus able to establish infection in a host cell.
- Virus = No metabolic activity yet (needs to infect something)
Virus families are denoted with the suffix _______.
-viridae (herpesviridae)
Virus genera are denoted with the suffix ______
-virus (simplexvirus)
What is the viral family of the influenza viruses?
- Orthomyoxviridae
What is the viral family of HIV?
What about the genus?
- Retroviridae
- Lentivirus
What genuses are in the Herpesviridae family?
- Simplexvirus (Herpes Simplex 1 & 2)
- Varicellovirus (Varicella Zoster = chickenpox)
What is the viral family of the Hepatitis viruses?
What about the genus?
- Hepadnaviridae
- Hepadnavirus
What are the five phases of viral replication?
- Adsorption
- Penetration
- Synthesis
- Maturation
- Release
What is the process of viral adsorption?
- Attachment of virus to host cell via spike protein
What is the process of viral penetration?
What is it called if the entire virus enters the cell?
- Entry of virions (or genome) into host cell
- Uncoating
What is the process of viral synthesis?
- Creation of new nucleic acids, capsid proteins, & other viral components.
What is the process of viral maturation?
- Assembly of newly created viral components into complete virions.
What is the process of viral release?
- Release of new virions from host cells.
What two types of viral release exist? Differentiate the two.
- Lytic → rupture of host cells, fast & self-limiting (think GI virus)
- Lysogenic → Slow release, makes host cell become viral factory. Can become lytic eventually.
What is the prototypical, first antiviral drug?
What is its mechanism of action?
- Acyclovir
- Inhibition of viral DNA synthesis
What is the indication for Acyclovir?
HSV & VZV
What is acyclovir’s mechanism of action?
- Impersonates the deoxyribose sugar of a DNA chain. Missing a hydroxyl group so the chain ends up terminating.
When is acyclovir indicated?
Does this change for pregnancy?
- HSV 1 & 2, and VZV infections.
- Beneficial in pregnant women, ↓ viral shedding and ↓ c-section rate.
What viral component allows HIV to bind to CD4⁺ T-lymphocytes?
- gp120 spike protein
Which antiviral is a inhibitor of reverse transcriptase?
What is the therapy called when this drug is combined with others to treat HIV?
- Azidothymidine (AZT) Zidovudine
- Highly Active Antiretroviral Therapy (HAART)
Which drugs have activity against both HBV and HIV?
- Lamivudine
- Telbivudine
- Tenofivir
When would one use Tenofivir?
- HIV & HBV
- Lamivudine-resistant HBV
How do Lamivudine & Telbivudine work?
- Inhibition of HBV DNA polymerase
- Inhibition of HIV reverse transcriptase
Interferon can be used for ____________ but it’s better at treating _______ ________.
viruses ; autoimmune diseases
What antivirals are available to treat influenza?
- Oseltamivir (Tamiflu)
- Zanamivir (Relenza)
- Baloxivir Marboxil (Xofluza)
When must tamiflu be give to be successful?
How much efficacy do antiviral influenza drugs have?
- 48hrs
- Usually shorten course of illness by 1 day.
Who should not be given Relenza (Zanamivir) for their influenza infection?
Why?
- Patients with asthma & COPD
- Relenza is an inhaled medication
Which influenza antiviral is a one-time dose pill?
Who cannot receive this medication?
- Xofluza (Baloxivir Marboxil)
- Pregnant and/or breastfeeding mothers, & hospitalized or very ill patients
What human cell surface antigens are used to categorize influenza subtypes?
- Hemaglutinin (H1, H2, H3)
- Neuramindase (N1, N2)
What role does human hemaglutinin have influenza infection?
- Viral attachment to human cells
What role do human neuraminidases have in influenza infection?
- Cell Penetration
Between Flu A & Flu B, which is generally more severe?
- Influenza A.
Which Influenza subtype has less antigenic shift and is generally more mild?
Who is generally more affected?
Does this flu infect anything other than humans?
- Influenza B
- Children
- Seals
What is the progression of a COVID infection?
Attachment to ACE receptors → inflammatory mediators → WBCs → Cytokine Storm.
What severe outcomes can occur with cytokine storm?
- ARDS
- Multi-Organ Failure
- Hyperinflammation syndrome
- Death
What gene may be responsible for an increased susceptibility to COVID infection/severity?
- Alu Polymorphism in ACE receptors
What PO drug has been approved for COVID infection?
- Paxlovid
What parenteral drugs have been approved for COVID? Give their MOAs.
- Remdesevir - chain termination inhibiting new viral synthesis.
- MABs - block COVID entry into cells
