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 virus bacteria vs virus
bacteria are self-reproducing, without a host i.e. by cell division
viruses are not self-reproducing as they need a host cell (such as bacterial cell) to multiply; as a result the host cell dies
bacteria are able to grow, feed and excrete
viruses lack any metabolic functions so they do not grow, feed or excrete
bacteria contain organelles such as cytoplasm, cell wall and nucleus which all perform specific functions
viruses consist only of genetic material and protective coating; no cell wall so antibacterials have no effect on virus
bacteria are (many times) larger than viruses
viruses are smaller than bacteria (100X)
bacteria have more complex DNA
viruses have simpler DNA
bacteria mutate/multiply slower than viruses
viruses mutate/multiply (much) faster than bacteria – resistance!
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 HIV viruses can mutate rapidly – so many strains
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
sociocultural issues: discrimination, stigma, religion

10. Examples of Viruses