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Microbiology Block 1 > RNA viruses (Influenza) > Flashcards

Flashcards in RNA viruses (Influenza) Deck (40):
1

what is the biology of Influenza A/B/C virus?

enveloped single stranded RNA segmented

2

what is the worst influenza virus?

type A

3

what influenza virus type is the mildest?

B and C

4

influenza A/B/C belongs to what virus family?

orthomyxo family of viruses

5

what enzyme do single stranded -RNA carry around for replication?

RNA Dependent RNA Polymerase (RDRP)

6

what is the mechanism used for replication in single stranded -RNA?

-RNA genome transcribed to mRNA and then a full +RNA using RDRP

7

how many segments does influenza A/B/C have?

8

8

what is characteristic about the influenza envelope?

it has spikes made of Haemagglutinin and Neuraminidase

9

what is the clue to determine what influenza strand is which (A/B/C)?

looking at the envelope for Neuraminidase protein

or

at the matrix for M1 or M2 protein

10

what determines the sub-types of influenza A/B/C?

Hemagglutinin

Neuraminidase

11

what is important about the M2 protein found in influenza?

1) they form proton channels in the membrane

2) promote uncoating and viral genome release

12

what inhibits the function of the M2 protein in influenza?

amantadine

remantandine

13

what does influenza use to bind to RBC's?

haemagglutinin

14

the VAP of influenza will bind to epithelial cells using what receptor?

 

sialic acid receptors

15

what mechanism is used to protect the cell from the influenza VAP?

 neutralization by using antibodies

16

what is the purpose of the neuraminidase enzyme in influenza?

it releases the mature virus from the cells

17

what drugs are used to target neuraminadase in influenza?

Zanamivir

Oseltamivir

18

how is influenza transmitted?

aerosol

19

during what months is it mostly common?

during winter

20

Influenza type A is found in what animal?

birds, human, pigs

21

influenza type A will spread using what mechanims?

antigenic shift (causes pandemics) and antigenic drift (causes localized epidemics)

22

in what species is influenza B and C found?

only in humans

23

influenza type B and C undergoes what type of epidemiology?

antigenic drift only (causes localized epidemics)

24

what is an antigenic drift?

accumulation of point mutations causing changes in Neuroaminidase and Haemagglutinin

25

what is antigenic shift?

acquiring completely new haemagglutinin and neuroaminidase proteins from gene re-assortment

26

what facilitates antigenic shift in influenza type A?

ability to infect human and animal species causing their RNA segmenst to mix 

27

where will influenza generally establish the infection?

in the upper and lower respiratory tract

28

when are systemic symptoms in influenza seen?

when interferon and lymphokine respond to the virus

29

what is needed to resolve infection by influenza?

cell mediated immunity and interferon

30

death by influenza is most common by what?

opportunistic infections, 

specifically Staph. aureus

31

when there is a antigenic drift, what immunity will we have?

we will have only partial protection

32

if there is a antigenic shift, what immunity will we have?

the population is completely susceptible

33

what are the clinical signs seen in influenza?

high fever

chills

myalgia

fatigue

sore throat

34

what will influenza cause in kids under 3 y/o?

Upper and lower Tract infection

croup

vomiting

35

what are the complications that can occur in influenza infection?

1) viral pneumonia (Acute Resp. Distress Syndrome)

2) 2ry bacterial pneumonia (S.Aureus)

3) Myositis (kids)

4) Reyes Syndrome (aspirin administration to children)

5) Guillain-Barre Syndrome

36

what is the most common cause of death in the elderly with Influenza?

2ry bacterial pneumonia

37

what is used to treat influenza?

how are these administered and when?

rimantadine and amantadine

zanamivir and oseltamivir

 

they must both be administered early after exposure

38

how is influenza prevented?

inactivated vaccine (flu-shot)

and live attenuated strain (flu-mist)

39

what strains does the inactivated influenza vaccine have?

type A and B

40

what causes the need for a new shot every year?

antigenic drift