July 26 Flu

not sure how much I'll get with just one hand but I'll give it a go:

x ray of my hand, you can see the dislocation of the ulna upward from the normal position

Review:
group work: 5 top ways (activities) to get HIV

Why HIV/AIDS is unusual:

Why no vaccine: 
            -HIV evolves rapidly (many strains and types) 
            -Ethical testing of vaccine?

Transmission depends upon many factors:
          - viral load of the body fluids varies
         - body fluid has cells? 
        - case of entry of virus into bloodstream 
                * trauma (rape, or anal) 
                * presence of other sexually transmitted diseases

Transmission of HIV
********(Ranked in order of likelihood of infection) group work question********

1. blood or blood products introduced IV
      * blood transfusion with contaminated blood (untested)
      * contaminated clotting factor
      * IV drug users: needle sharing
 1b miscellaneous blood or body fluid exchange
2. perinatal (placental or during birth)
3. rape/ anal intercourse as receiving partner
4. vaginal intercourse as receiving partner
5. sexual intercourse as donating partner or oral sex

Topic 8b: Influenza

*old flu, bird flu, swine flu
pic: kid kiss pig

Influenza viruses

Type A: world wide pandemics, infect all mammals and birds

Type B:small epidemics in vulnerable populations, infect mammals only

Type C:infect mammals only, rarely causes disease in humans

Structure of Type A  (Box. p. 736)

Genome: RNA virus : 8 strands/ inside capsids

Enveloped

with matrix protiens: ion channel M2

Two important peplomer types:

Hemagglutinin

Function:host cell binding

Blocked by drugs: amantidine/ rimantidine (blocks uncoating)

Neuraminidase

Function: helps release progeny

Blocked by drugs: Tamiflu & Relenza (only these 2 drugs work on swine flu and bird flu)

Why do you need a new shot every year?

The viruses change!

*body recognizes virus by anatomical parts (antigen)

HA –hemagglutinin antigen

NA –neuraminidase antigen

We identify flu viral types by:

* numbering antigens
*location/date first isolated in humans

sleeve from flu shot: split virion inactive ultra violet, centrifug.....

Flu “shot” is: soluble subunit

Flu-mist vaccine is: live attenuated virus

list if year by year flu shot

3 Viral types seen in annual seasonal vaccines are:   
             *Two type A (H1N1 and H3N2) and one type B

*high rate of genetic (thus antigenic) change within & between flu seasons
*vaccine is a cocktail of international influenza committee's best guess for this year's strains
           

Two means of genetic change in flu viruses:  Fig. 25.38

Antigenic Drift

* tiny mutations introduce small antigenic changes (RNA virus more mutations)
* gradual changes in viruses over time

fig 25.38

Antigenic Shift

(reassortment)
*2 flu viruses infect same host cell
*New viral hemagglutinin (or less commonly, neuraminidase) in existing viruses

*****break*****

Connections between human / pig / bird flu viruses:

* humans and pigs can share viruses
* pigs and birds can share viruses
* humans normally can't get it directly from birds

*pigs are mixing pot where human, pig, and bird virus can co-infect same cell

*****draw this?***draw human cell and human flu and able to match receptor proteins and infect cell....pigs and humans both have human and pig flu receptors..wild card birds....share with pigs not human*****

* non human flu viruses are very different from human viruses(all 8 RNA strands and all

Why is the new H5N1 bird flu virus of concern?

highly lethal/ virulent: rare human cases of bird flu are often lethal
* (but so far. poorly passed from person to person): mutation needed to be pandemic

Why is the new H1N1 swine flu virus of concern?

* is moderately virulent in US

       * return highly virulent like 1918-1919 "Spanish flu"
* Easily passed from person to person

Where do flu viruses live between epidemics?

* probably reservior animals
* migratory or domestic birds

*****group activity*****
*does this image antigenic drift or shift? define both . why