Antivirals Classes and Issues Flashcards
Describe two methods of preventing viral infection
Vaccines are the mainstay of preventing viral disease in animals
Biosecurity important in production animals
Give 6 targets of antiviral drugs
Entry Uncoating Replication Assembly Release Immune Responce
Name three types of antiviral therapies
Drugs which target viral proteins e.g. inhibition of virus replicative enzymes Drugs which target host proteins e.g. blocking receptors Drugs which enhance host defenses e.g. interferons
Describe the process of inhibition of viral uncoating and give an example of a drug that does this
Influenza A H+ causes HA to fuse with membrane H+ ions enter virion via M2 Leads to release of nuceoprotein from virus core Amantadine blocks M2
Describe Nucleot(s)ide analogues and their action
Nucleot(s)ide analogues
Typically need to be activated by cellular or viral enzymes
Specificity is higher if:
Virus enzyme activates drug more readily
Drug is more potent against viral polymerase than host polymerase
Give examples of nucleotide analogues
e.g. acyclovir (herpesviridae), zidovudine (HIV)
incorporated into viral genome and stops elongation
Desribe antivirals that inhibit genome replication
Antiretroviral drug
Non-nucleotide reverse transcriptase inhibitors e.g. nevirapine
Bind near catalytic site of RT
Do not bind to or inhibit host enzymes so highly specific
BUT resistance develops very rapidly and needs only a single amino acid substitution
How do integrase inhibitors work against HIV
Binds to viral integrase to prevent viral cDNA from being inserted into host genome
Describe the function if protease inhibitors
Where viral proteins are produced as polyproteins and require cleavage by a protease this is a good drug target
Used for HIV, hepatitis C in man
Describe the action of neuraminidase inhibitors
Prevent release of influenza virus from cells
Which drugs boost the innate immune response to viruses
Interferons Toll like receptor stimulation e.g. Imiquimod – TLR7, 8. equine sarcoids “Snakeoils” e.g. staphylococcal protein A very little evidence from clinical trials
Describe the action of Lymphocyte T Cell Immunomodulators
Increase CD-4 lymphocyte function Increase CD-4 lymphocyte numbers Increase IL-2 production Increase red cell counts in severely anemic cats Induce platelet recovery
What has LTCI treatment proven useful for?
Feline Herpes Virus
- three weekly injections of LTCI significantly increased lymphocyte counts and increased the quality of life as determined by clinical scores
Describe factors that lead to non adherence in patients with HIV and give its relevance for veterinary surgeons
- Increased time of treatment
- Increased pill number
- Increased side effects
All reduce the patients adherence
This is important as it is a point of consideration for the kind of treatment prescribed (adherence really important for the efficacy of the HIV treatment - good to adapt treatment to increase adherence)
Define adherance
The degree to which the patients behaviour corresponds with the agreed reccomendations from the health provider
