RNA viruses (Influenza)

Question 1

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

Answer 1

enveloped single stranded RNA segmented

Question 2

what is the worst influenza virus?

Answer 2

type A

Question 3

what influenza virus type is the mildest?

Answer 3

B and C

Question 4

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

Answer 4

orthomyxo family of viruses

Question 5

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

Answer 5

RNA Dependent RNA Polymerase (RDRP)

Question 6

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

Answer 6

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

Question 7

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

Answer 7

8

Question 8

what is characteristic about the influenza envelope?

Answer 8

it has spikes made of Haemagglutinin and Neuraminidase

Question 9

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

Answer 9

looking at the envelope for Neuraminidase protein

or

at the matrix for M1 or M2 protein

Question 10

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

Answer 10

Hemagglutinin

Neuraminidase

Question 11

what is important about the M2 protein found in influenza?

Answer 11

1) they form proton channels in the membrane
2) promote uncoating and viral genome release

Question 12

what inhibits the function of the M2 protein in influenza?

Answer 12

amantadine

remantandine

Question 13

what does influenza use to bind to RBC’s?

Answer 13

haemagglutinin

Question 14

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

Answer 14

sialic acid receptors

Question 15

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

Answer 15

neutralization by using antibodies

Question 16

what is the purpose of the neuraminidase enzyme in influenza?

Answer 16

it releases the mature virus from the cells

Question 17

what drugs are used to target neuraminadase in influenza?

Answer 17

Zanamivir

Oseltamivir

Question 18

how is influenza transmitted?

Answer 18

aerosol

Question 19

during what months is it mostly common?

Answer 19

during winter

Question 20

Influenza type A is found in what animal?

Answer 20

birds, human, pigs

Question 21

influenza type A will spread using what mechanims?

Answer 21

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

Question 22

in what species is influenza B and C found?

Answer 22

only in humans

Question 23

influenza type B and C undergoes what type of epidemiology?

Answer 23

antigenic drift only (causes localized epidemics)

Question 24

what is an antigenic drift?

Answer 24

accumulation of point mutations causing changes in Neuroaminidase and Haemagglutinin

Question 25

what is antigenic shift?

Answer 25

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

Question 26

what facilitates antigenic shift in influenza type A?

Answer 26

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

Question 27

where will influenza generally establish the infection?

Answer 27

in the upper and lower respiratory tract

Question 28

when are systemic symptoms in influenza seen?

Answer 28

when interferon and lymphokine respond to the virus

Question 29

what is needed to resolve infection by influenza?

Answer 29

cell mediated immunity and interferon

Question 30

death by influenza is most common by what?

Answer 30

opportunistic infections, specifically Staph. aureus

Question 31

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

Answer 31

we will have only partial protection

Question 32

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

Answer 32

the population is completely susceptible

Question 33

what are the clinical signs seen in influenza?

Answer 33

high fever chills myalgia fatigue sore throat

Question 34

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

Answer 34

Upper and lower Tract infection croup vomiting

Question 35

what are the complications that can occur in influenza infection?

Answer 35

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

Question 36

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

Answer 36

2ry bacterial pneumonia

Question 37

what is used to treat influenza? how are these administered and when?

Answer 37

rimantadine and amantadine zanamivir and oseltamivir they must both be administered early after exposure

Question 38

how is influenza prevented?

Answer 38

inactivated vaccine (flu-shot) and live attenuated strain (flu-mist)

Question 39

what strains does the inactivated influenza vaccine have?

Answer 39

type A and B

Question 40

what causes the need for a new shot every year?

Answer 40

antigenic drift