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

•

DISEASE VIRUSES

AIDS HIV

WartHerpes Simplex Virus

Flu Influenza

Measles Morbillivirus .

Cancer Hepatitis 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

http://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/adlyt.html

Phase I

Phase II

Phase IV Phase V

Phase 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