Virology Chapter 7

Question 1

What is the genome of influenza

Answer 1

segmented (-) ssRNA genome

Question 2

what type of influenza causes the most of the seasonal epidemics of disease

Answer 2

influenza A and B

Question 3

what influenza causes mild illness in humans

Answer 3

influenza C

Question 4

what influenza infects cattle rather than humans

Answer 4

influenza D

Question 5

is influenza acute, persistent, latent or oncogenics, and why?

Answer 5

it’s acute because it’s highly contagious and fast

Question 6

influenza viruses are typically transmitted from one person to the other by what route

Answer 6

respiratory

Question 7

What is the structure of the influenza virus

Answer 7

many shapes (pleomorphic)
spherical / ovoid
80-120 nm

Question 8

Is the influenza virus naked or enveloped

Answer 8

enveloped == lipid bilayer with spike proteins (glycoproteins)

Question 9

What are the 2 types of glycoproteins

Answer 9

Hemaglutinin (H) and Neuraminidase (N)

Question 10

What are the 2 important envelope proteins

Answer 10

M1 and M2

Question 11

What is the function of H/HA

Answer 11

Trimer, bind to Sialic Acid (virus receptor)

Question 12

What is the function of N

Answer 12

Tetramer; used for when viruses want to detach after replication cycle is completed

Question 13

What is M2

Answer 13

ion channels that cause protons (H+) to enter the interior part of the virus (for acidification)

Question 14

What is M1

Answer 14

lines the inside of the envelope so the nucleocapsid, envelop and glycoproteins assemble correctly
- when acidification happens, genome is released from M1 protein

Question 15

How many genes does the influenza A genome have

Answer 15

10

Question 16

and how many molecules are these genes distributed to

Answer 16

8 segments of (-) sense RNA molecule

Question 17

each segment is replicated and transcribed…

Answer 17

independently

Question 18

each segment is coated with…

Answer 18

Nucleoprotein (NP) and RNA Polymerase Complex

Question 19

These segments are called RNPs (Ribonucleoproteins). What are RNPS composed of?

Answer 19

(-) RNA, NP, and RDRP (PA, PB1, PB2)

Question 20

why are there multiple copies of NP?

Answer 20

because NP binds to 20 nucleotides in the RNA strand

Question 21

How many subtypes of H and N are there in influenza A

Answer 21

18 and 11

Question 22

Influenza A’s natural host is the

Answer 22

dabbling ducks, however some adapted to infect humans better

Question 23

In humans, influenza A results in respiratory disease (upper), what cells does it infect

Answer 23

epithelial cells of the airway

Question 24

What 5 categories are in an influenza strain

Answer 24

antigenic type (A/B/C/D)
host of origin = animals only
strain number
year isolated
virus subtype (H…N..)

Question 25

Strains are chosen to make vaccines, how are they chosen?

Answer 25

by surveillence data and forecasts, so which viruses are circulating, and which are mostly to circulate

Question 26

Influenza viruses typically infect the ..... tract of domestic and wild birds

Answer 26

gastrointestinal

Question 27

What are the symptoms of influenza

Answer 27

headache fever runny nose sore throat coughing muscle ache vomiting

Question 28

How can influenza result in serious complications

Answer 28

when there is a bacterial infection caused when your immune system is down

Question 29

virus enters through

Answer 29

inhalation and transfer to mucosal surfaces

Question 30

N-acetylneuraminic acid is another word for

Answer 30

sialic acid

Question 31

where is sialic acid found

Answer 31

mucoproteins, = cells in the respiratory tract

Question 32

Why are pigs called mixing vessels

Answer 32

because they can infect humans (strain a) and birds (strain b)

Question 33

What are the most common influenza A strains

Answer 33

A(H1N1) and A(H3N2)