medicines and drugs

1. medicines and drugs antivirals

2. Diseases caused by viruses • influenza • SARS • measles • smallpox • AIDS • avain flu • Polio • meningitis (can be both bacterial and viral) • pneumonia (also caused by both bacteria and viruses)

3. virus

4. antivirals • treat viral infections • usually virus specific – not broad • not that many antivirals available • do not destroy but inhibit development of target virus • Does not destroy host cell • pills, liquids, inhalers, intravenous

5. bacteria vs virus

6. Ways in which antiviral drugs work • Changes the cell membrane which prevents virus from entering cell. • preventing viruses from using the host cell to multiply by 1.altering the genetic material or 2.preventing enzyme activity of the host cell . • preventing the viruses from leaving the cell after reproducing inside the host cell.

7. Viral infections are harder to treat because… • viruses mutate much more quickly so: • they can adapt to drugs (new flu vaccine every year) or • they can evade human immune system response (antibodies) • bacteria are more complex and thus can be targeted in more ways - viruses lack subunits/functions which are normally targeted by antibacterials e.g. cell walls. • bacteria can be killed or their actions reduced by simple chemical agents but viruses cannot be killed (only stopped reproducing) and must be targeted on genetic level • different types of bacteria employ similar metabolic processes and thus can be targeted by common antibacterials whilst each kind of virus usually requires a specific drug.

8. AIDS (is a retrovirus – genetic material is in the form of RNA – not DNA) AIDS is syndrome caused by HIV which invades T4 cells which are a type of white blood cell (part of immune system). • Virus binds to receptor proteins and penetrates the cell • HIV releases RNA into the cell and uses the cell to make viral DNA • Viral DNA integrates into the cell’s own DNA and replicates when the cell divides • Virus is produced within the cell wall, and released when the host cell dies.

9. AIDS Treatment of AIDS is problematic because • HIV viruses can mutate rapidly – so many strains • HIV viruses have similar metabolism to the metabolism of the host cell so any drug could also damage host cell • antiretroviral drug targets are white blood cells which meant to protect us against other pathogens • HIV lies dormant for a while so immune system is not responding • socioeconomic: high price of antiretroviral drugs, access to drugs • socioculturalissues: discrimination, stigma, religion

10. Examples of Viruses