Treatment of Viral Infections Flashcards
Describe the viral replication cycle
1) Viruses fuses to host cell membrane
2) Enters via endocytosis
3) Uncoats –> expelling contents into host cell
4) Viral RNA converted into ds DNA by reverse transcriptase
5) Newly formed DNA crosses nuclear membrane and integrates into host genome via integrase
6) Translation of viral proteins the DNA transcript
7) Viral proteins migrate to cell surface
8) Exit cell via ‘budding’
9) Immature vision migrates away and protease cleaves the immature viral proteins and allows assembly and maturation to form new infective virus
List the phases of the HIV replication cycle that can be inhibited by drug treatment
Entry/fusion, reverse transcriptase, integrase and protease inhibitors.
List the drugs that can inhibit each stage of the viral life cycle
Reverse transcriptase inhibitors (NRTIs, nucleoside analogue RT-inhibitors) – didanosin, stavudin, zalcitabin, zidovudine
Protease inhibitors – rinoavir, saquinavir, indinavir
List the stages of the influenza life cycle that can be inhibited by drugs and the drugs concerned
> M2 protein inhibitors (amantadine and rimantidine) – prevents uncoating and re-coating of virions
Inhibition of RNA polymerase (ribavirin) – prevents formation of proteins used in the formation of new, immature virions.
Neuramidase inhibitors (zanamavir, Tamiflu) - prevents the aggregation of virions and reduces the inactivation of viruses by respiratory tract mucus.
Describe the structure of the influenza A virus
orthomyxovirus (a single stranded RNA virus) and presents with surface spikes of haemagglutinin (HA) and neuraminidase (NA) protein
How can changes in the influenza A virus lead to epidemics and pandemics?
If there are antigenic shifts of the HA surface protein, this results in pandemics (whole population). If there are antigenic shifts of the HA and NA proteins, this results in epidemics.
