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what is the basic viral replication cycle?
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what are the forms of viral transmission?
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what are the targets for antiviral drugs?
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virus adsorbtion
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vector transmission
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proteins that can be inhibited, particularly proteins that are conserved across species (and are dissimilar to human proteins)
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virus penetration
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airborne or droplet transmission
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uncoating
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fecal-oral transmission
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expression of virus genome translation/transcription
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direct contact
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genome replication
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indirect contact
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protein synthesis
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assembly
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vertical transmission
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release of virions
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what are the 3 types of viruses?
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how do they replicate?
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what is an example of each?
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DNA viruses
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using DNA polymerase
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poxviruses (e.g. smallpox), herpesviruses (e.g. shingles), papillomaviruses (e.g. HPV)
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RNA viruses
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various methods
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rhinoviruses (e.g. common cold), coronaviruses (e.g. Sars- CoV-2), influenza, rabies, measles
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retroviruses
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genome is comprised of RNA, but the virus converts this back into DNA and inserts a DNA copy of its genome into the host genome
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human immunodeficiency virus (HIV) 1 and 2, human T-lymphotropic viruses (HTLV)
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what are the main types of antiviral drugs?
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what are their mechanisms of action?
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attachment inhibitors
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the drug will bind where the virus attaches, blocking the virus from binding
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entry inhibitors
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blocks the virus from fusing to the cell membrane
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uncoating inhibitors
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blocks the virus from uncoating within the cell
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protease inhibitors
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uses protease to stop the virus from being release from the cell
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polymerase inhibitors
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inhibit replication or reverse transcription
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neuraminidase inhibitors
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blocks the virion particles from being release from the cell
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reverse transcriptase inhibitors
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blocks retroviruses from being able to perform reverse transcription
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integrase inhibitors
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blocks the virus from integrating with the host DNA
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what is influenza?
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what drug type is most commonly used to treat influenza?
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how does it treat influenza?
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an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae
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neuraminidase inhibitors
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their active metabolites competitively inhibit influenza virus neuraminidase enzymes, which stops influenza virions from being released from the cell
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how do human immunodeficiency viruses (HIV) replicate?
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what is the frontline treatment option for HIV?
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how do we use it to treat HIV?
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they are retroviruses, so they reverse transcribe their RNA genome into DNA, and insert it into the host cell genome
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highly active antiretroviral therapy (HAART)
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administer a combination of 3 antiviral drugs (typically 1 non-nucleoside reverse transcriptase inhibitor and 2 nucleoside reverse transcriptase inhibitors, plus an integrase inhibitor)
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what are the drugs used in this treatment?
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what are their mechanisms of action?
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dolutegravir
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it is an antiretroviral integrase inhibitor, and works by blocking the integrase enzyme needed to allow the viral DNA to integrate into the host genome, meaning the retrovirus cannot replicate
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lamivudine
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it is a nucleoside reverse transcriptase inhibitor whose active metabolite blocks the reverse transcription of HIV RNA into DNA
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tenofovir disoproxil
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is a nucleotide reverse transcriptase inhibitor whose active metabolite blocks the reverse transcription of HIV RNA into DNA
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