Facts about Influenza Viruses There are three types of influenza viruses: A, B, C A is most serious and it can genetically change rapidly and is the one that caused the pandemics (worldwide spread) The virus’s genetic material is single stranded RNA The viral envelope has proteins (antigens) on it which can be used to identify each virus and put them into groups: hemagglutinin and neuraminidase Influenza viruses are named like this: Type, place of initial isolation, strain designation and year of isolation. Example: A/HongKong/H1N3/68. H and N stand for the surface proteins There are medicines to treat flu: Tamiflu and Relenza A new vaccine must be made for each new flu, to make a new vaccine for millions of people takes 3-6 months

DISEASEVIRUSES AIDSHIV Wart Herpes Simplex Virus FluInfluenza MeaslesMorbillivirus. CancerHepatitis B Introduction – Structure – Replication – Virology – Medicine - Review Examples of some viral diseases:

Human flu, bird flu, pig flu-what’s up?? Humans, birds and pigs all get their own versions of the flu These flu viruses are usually mild and we have built up IMMUNITY or resistance to our own kind of flu Usually the people types (strains) don’t make pigs or birds very sick and visa versa VERY RARELY mutations in a virus occurs and these genetic changes allow a virus to ‘jump’ species from say pigs to people or birds to people VIOLA SWINE AND AVIAN FLU outbreaks in people The jumping pig or bird virus will cause more serious flu in people because people have not had a chance to become resistant to it SO WE GET THE NEWSPAPER HEADLINES The most serious flu is AVIAN FLU but it does not transfer readily to people

Replication Phases V - Release -Assembly of virus DNA and protein coat into whole new viruses -Leaving the cell Phase I Phase II Phase IV Phase VPhase III Introduction – Structure – Replication – Virology – Medicine - Review I, II, III - Viruses enter cell -Attachment to cell membrane -Penetration inside cell -Losing virus protein coat IV - Replication -Tricks cell into making more viral DNA -Tricks cell into making viral protein coat