Final; Respiratory Viruses Flashcards Preview

SP14 Microbiology > Final; Respiratory Viruses > Flashcards

Flashcards in Final; Respiratory Viruses Deck (50):
1

What are the three types of influenza

A, B , and C (the most rare)
type A is the most common and associated with the greatest concern

2

What is the genome of influenza

-ssRNA in 8 segments

3

What type of virion is influenza

enveloped

4

What are the special surface antigens of influenza

16 HA (hemagglutinin) serotypes
9 NA (neuraminidase) serotypes

5

What is a major determinant for human to human transmission of influenza

HA

6

Which type of influenza has an animal reservoir

type A; mostly waterfowl
the pig is a key between bird and human transmission

7

True or False
HAs role is cell attachment and entry is poorly understood

False; it is well understood

8

What triggers the conformation change after virus and host cell membrane attachment

pH change of the endosome

9

The conformation change of the membranes triggered by the pH change causes what

membrane fusion; this is a model for all enveloped viruses

10

Where does transcription of influenza take place

in the nucleus; exception to the rule (it has -ssRNA)

11

The protected genome (RNP core) escapes the nucleus and buds from the cell via the use of this protein

NA

12

How is influenza transmitted

aerosol, large and small droplets

13

When is the infectivity the greatest for influenza particles

When they are the smallest, they can penetrate the deep lung

14

What is the incubation period of influenza

1-4 days
contagious days before symptom onset to 5 days letters; children infectious for longer

15

What are the symptoms of the seasonal flu

fever, malaise, nonproductive cough, sore throat
lasts 3 to 7 days after symptoms develop

16

What are the current circulating strains of influenza and its contagiousness

H3N2, H1N1
reproductive numer = 1:2

17

What are some complications of influenza

viral pneumonia
bacterial pneumonia
reye synrome (type B + aspirin)
otitis media

18

What type of vaccine is the influenza vaccine

attenuated live; donor virus with wild type HA/NA epitopes

19

Why is a new influenza vaccine required each year

antigenic shift, the vaccine usually contains H3N2, H1N1, and type B

20

What is used to prevent/control influenza

antiviral treatment
tamiflu
supportive care

21

What are the 4 major pandemics of influenza

1918 Spanish Flu (H1N1)
1957 Asian Flu (H2N2)
1968 Hong Kong Flu (H3N2)
2009-2010 H1N1

22

Highly pathogenic avian influenza (HPAI) contains what strains (and low pathogenic)

H5 or H7; has multi-basic residues at HA cleavage sites allowing replication throughout the body (of birds)

23

What are the symptoms of HPAI

skin lesions, necrotic and swollen combs, systemic infection (of birds)

24

True or False
H5 and H7 strains can mutate to HPAI strains

True

25

What is so controversial about the Dutch study involving H5N1

They used ferrets to model how H5N1 could infect humans which has a high mortality rate

26

What is used to characterize the adenovirus

serotype; different serotypes are associated with different diseases

27

What are the two most studied adenovirus serotypes

2 and 5

28

What is the genome of adenovirus

dsDNA

29

What is the virion of adenovirus

non-enveloped

30

How does adenovirus enter the cell

entry is triggered by coxsackie-adenovirus receptor (CAR)
pH triggers capsid disassembly

31

What is the method of gene expression of adenovirus

intermediate - early
early
late

32

What takes place during the intermediate-early phase of gene expression in adenovirus

E1A portion of genome
2 transcriptional regulators (cell and virus)

33

What takes place during the early phase of gene expression in adenovirus

5 genome sections
DNA replication and post transcriptional events

34

What takes place during late phase of gene expression in adenovirus

take over of cellular mRNA synthesis

35

What takes place during genome replication of adenovirus

it can be initiated at either end of the genome
5'-3'
displaced strand circularizes allowing template to be made
primed by the protein pTP

36

What is involved with cell cycle regulation of adenovirus

DNA replication occurs during S phase
not all cells are actively replicating

37

What does the E1A portion of adenovirus do to gene expression

it inactivates pRb leading to S phase

38

What does the E1B portion of adenovirus do to gene expression

it inactivates p53 leading to S phase and preventing apoptosis

39

The E3 gene of adenovirus produces what

proteins important to host immune evasion; blocks MHC-1 expression

40

E3 gene blocks what cytokines

TNF induced apoptosis
IFN-α and IFN-β keeping protein translation alive

41

With adenovirus, what disease is common

respiratory infections; 5-10% of all viral infections

42

What are the symptoms of adenovirus infections

common cold symptoms
nasal congestion, inflammation, cough

43

adenovirus also causes this disease which causes severe pneumonia in military troops (vaccine available for them)

actue respiratory disease

44

What makes adenovirus important involving research

it is frequently used as a vector

45

This is a frequent cause of mild upper respiratory infections

rhinovirus

46

Why is it impractical to develop a vaccine against rhinovirus

it has a large antigenic diversity; humans are the only reservoir

47

What does rhinovirus use to attach to host cells

attached to intercellular adhesion molecule 1 or the very low density lipoprotein receptor and extrudes its genome into the cell

48

What is the incubation/duration of rhinovirus

incubation is 1-4 days
duration 2-3 days with virus shedding sometimes up to 3 weeks

49

What are the symptoms of rhinovirus diseases

red nose, nasal discharge, epithelial damage due to immune response

50

What are the prevention strategies against rhinovirus

no vaccine
no antivirals; resistant mutants