ORTHOMYXOVIRIDAE

• Matrix protein (M)

• Nucleoprotein (NP)

2 major structural proteins of orthomyxoviridae

Influenza A, B, C

3 genera of viruses

• Influenza A

• 2 major proteins surface glycoproteins 

  • hemagglutinin (H) 

  • Neuraminidase (N) - mushroom shape spikes that release mature virions 

Hemaglutinin and neuraminidase

2 major proteins surface glycoproteins of influenza A

Neuraminidase (N)

• mushroom shape spikes that release mature virions 

true

is protein surfzce glycoproteins attached to sialic receptor?

true or false?

Influenza C

• Causes mild respiratory infection 

• Consist of 7 ssRNA

• Lack of neuraminidase vs Influenza A and B

Influenza c

influenza that has lack neuraminidase?

true

• Influenza season is may to october on southern and november to april at northern 

• Influenza virus is enveloped 

• Types A and B have 8 segments of ssRNA 

true or false?

true

• Helical capsid

• RNA-RNA dependent polymerase

true or false?

H antigen

• Membrane protein that is bind to host cell

N antigen

membrane protein that cleaves budding viruses = release virus

true

• H antigen bind to host cell

  • There are 16 H antigens 

  • H1-H3 most infection on human 

true or false?

true

• N antigen cleaves budding viruses = release virus

  • N1-N9 but N1-N2 are usually occuring

true or false?

Antigenic drift

• occur which is a minor change in antigenic structure as mutation happens that happens on Influenza A-C (every year)

  • RNA replication error

Antigenic shift

• change in surface proteins resulting in new H or N protein

  • 2 mechanism of antigenic shift

genetic assortment and adaptive mutation

• 2 mechanism of antigenic shift 

Genetic reassortment

• of 8 ssRNA strandsof 2 separate influenza viruses which swine influenza that can co infect to all 3 types of virus

• Genome of influenza goes to other virion resulting new strain 

Adaptive mutation

• novel virus slowly adjust and becomes transmissible from a mammalian 

Influenza A

Antigenic shift is only associated with?

Spanish flu

Influenza a (H1N1)?

• Causes 1st pandemic in 40 years 

  • Contains RNA from bird, humana and swine strains of virus 

H2N2

H1N1 Then switch to ____ which is asian flu 

hongkong flu

H3N2

H1N1 and H3N2

most dominant strain

H3N2v

non human influenza

H5N1

• the avian flu and appeared in flocks in asia causing low poultry production and isolated on birds in turkey 

true

• H1N1 causes pandemic

true or false?

true

• When virus normally circulate on animals but then transferred to human it is called variant viruses 

true or false

H7N9

• China influenza A

• 1-4 days

• Influenza incubation

true

• Fever can be 41 C

true or false?

Flocked swabs

collect more epithelial cells than rayons swabs

true

• Kits detect both A and B but not determined specifically 

• Culture that has influenza absorb RBC

true or false?

•  amniotic fluid cavity of embryonated chicken eggs and PMK and MDCK cells 

Influenza grows on?

amantadine and rimantadine

Antiviral drugs used are ______ and only effective for influenza A

Oseltamivir (tamiflu)

• but more expensive than amantadine but can cover you from A and B 

• amantadine 

 H3N2 is resistant to