Core Microbiology - Antivirals (3) Flashcards
Acute viral infection
RNA - doesn’t survive long
Examples of acute viral infections
Influenza, measles, mumps, hep A
Chronic viral infection
DNA based, latent or persistent
Chronic latent virus examples
Herpes simplex, CMV
Chronic persistent virus examples
HIV, Hep B, Hep C
Virus structure
Nucleic acid core (DNA/RNA), protein (coat, enzymes), lipid envelope
Virus replication
- Attaches to cell (receptor)
- Cell entry
- Virus uncoating
- Early proteins produced (enzymes)
- Replication
- Late transcription/translation
- Viral assembly
- Virus release
Polymerases
- DNA > DNA (eukaryotes, DNA virus)
- DNA > RNA (eukaryotes, DNA virus)
- RNA > RNA (RNA virus)
- RNA > DNA (retrovirus, HBV)
Nucleotide
Base, ribose sugar, triphosphate
Azidothymidine (AZT)
Inhibits HIV replication (Nucleoside Reverse Transcriptase Inhibitor)
NRTIs - pyrimidine analogues
- Thymidine analogues - Zidovudine
2. Cytosine analogues - Lamivudine
NRTIs - Purine analogues
(Adenine and Guanidine) Abacavir, Tenofovir
HBV
Contains reverse transcriptase enzymes - Lamividine and Tenofovir
NNRTIs
Anti-retrovrius, Efavirenz, Nevirapine
Protease inhibitors
Atazanavir, Darunavir, Fospamprenavir, Lopinavir, Nelfinavir, Ritonavir, Saquinavir
Viruses use of proteases
Have their own to make them into enzymes and function normally
HIV protease
Aspartate
New HIV drugs
- Fusion inhibitor
- Integrase inhibitors
- Chemokine receptor anatgonists
Fusion inhibitors
Mimic proteins that allow viruses to fuse with membrane (Enfuviritide)
Integrase inhibitors
Raltegravir
Chemokine receptor antagonists
Maraviroc (CCR-5) blocking helps prevent entry
Highly Active Antiretroviral Therapy (HAART)
2 NRTIs+NNRTI/2 NRTIs + boosted PI
Started when CD4 falls, switch off virus replication, taken life long, suppression >10 years achieved
Problems with HAART
Liver toxicity and triglyceride problems (heart disease)
HIV cure
Suppressed on antivirals, CD4 lymphocytes destroyed by conditioning, stem cells, antiviral therapy stopped
Hep C virus
Interferons and Ribavirin, not have interferon free regimens >90% cure
Interferon problems
Depression, flu-like symptoms, not directly acting non-specific
Aciclovir
Nucleoside anaylogue, phosphorylated by HS thymidine kinase
HSV and VZV
Ganciclovir
CMV
Oseltamivir and Zanamavir
Neuraminidase inhibitor (Influenza)
Ribavirin
Hep C virus and RSV
Interferons
Hep C virus and Hep B virus