Respiratory Viruses Flashcards Preview

Micro and Immuno - Exam 2 > Respiratory Viruses > Flashcards

Flashcards in Respiratory Viruses Deck (41)
Loading flashcards...
1
Q

Influenza Genome

A

segmented (-)ssRNA

2
Q

Influenza Virion

A

Enveloped

3
Q

Influenza Incubation

A

1-4 days

4
Q

Influenza Strains

A

Three types: A, B, C
A is the most common
H3N2 and H1N1 are in circulation right now

5
Q

Influenza Replication

A

In the nucleus, but the protected genome (RNP core) escapes the nucleus and buds from the cell surface

6
Q

What are the major surface antigens of Influenza

A

HA and NA

7
Q

What is the role of HA for influenza, and how many serotypes are there?

A

Cell attachment

16

8
Q

What is the role of NA for Influenza, and how many serotypes are there?

A

Viral budding and release

9

9
Q

What is the difference between Avian and Human strains of Influenza?

A

The linkage of HA is the major determinant
Avial = a2,3 linkage
Human - a2,6 linkage

10
Q

Influenza Symptoms

A

Fever, malaise, nonproductive cough, sore throat
Symptoms have a 1-5 day onset (can be longer in children)
Symptoms last 3-7 days after they develop

11
Q

Influenza Transmission

A

Aerosol, large and small droplets

Contagious a day before symptoms even occur

12
Q

Influenza Prevention

A

Vaccine - live attenuated

  • Antigens shift every year, that’s why we need one every year
  • vaccine contains H3N2, H1N1, and Type B strains; Type A is generated through reassortment via coinfection
13
Q

Influenza Treatment

A
Antiviral treatments
-Amantidine, rimantidine
-these block viral entry
-resistance development is common
Tamiflu
-blocks release of budding virions
14
Q

Avian Influenza

A
H5N1
H5 or H7 strain
lethal in >75% of 6-8 week old chicks
HPAI strains have multi-basic residues at HA cleavage sit allowing replication through the body
H5 and H7 can mutate to HPAI strains
15
Q

Low Pathogenic Avian Influenz

A

Asymptomatic to slight respiratory infection, no lesions

16
Q

What was the controversy surrounding the Dutch research regarding Avian Influenza?

A

Tried to find out if H5N1 strain can adapt to humans (high mortality rate)
Passaged virus in ferrets (as human model)
After 10 generations, the virus was capable of airborne transmission between animals

17
Q

Adenovirus Genome

A

dsDNA

18
Q

Adenovirus virion

A

Non-enveloped

19
Q

Adenovirus Strains

A

Characterized by their serotype
Different serotypes are associated with different diseases
Ad 2 & 5 are the most frequently studied

20
Q

Adenovirus replication

A

In the nucleus
Initiated on either end from 5’ to 3’ end; one strand gets displaced
The displaced strand circularizes to allow template copy to be made
Primed by the protein pTP - unusual priming strategy

21
Q

What are the 3 gene expression phases of Adenovirus?

A

Immediate-Early
Early
Late

22
Q

Immediate-Early phase of Adenovirus gene expressoin

A

E1A portion of gene
2 transcriptional regulators - cell and virus
Necessary to reach the early stage

23
Q

Early phase of Adenovirus gene expression

A

5 genome sections:
E1B, E2, E3, E4, L1
DNA replication and post-transcriptional evnts

24
Q

Late phase of Adenovirus gene expression

A

Take over mRNA synthesis

25
Q

What does the E1A protein of Adenovirus effect?

A

Inactivated pRb, leading to S phase gene expression

26
Q

What does the E1B protein of Adenovirus effect?

A

Inactivates p53 - leading to S phase and preventing apoptosis

27
Q

What does the E3 gene protein of Adenovirus effect?

A

Produces proteins important to host immune invasion

28
Q

How does Adenovirus effect the host cell immune system?

A

Blocks MHC class I expression - reducing CTL cell killing
Blocks TNF induced apoptosis
Blocks INF-a and INF-B action - keeping protein translation alive

29
Q

Adenovirus symptoms

A

Respiratory infections are very common
Similar to common cold
Acute respiratory disease (ARD) - severe pneumonia, seen in military recruits, crowded conditions

30
Q

Adenovirus Prevention

A

Vaccine is available for milirary personnel 17-50 years old

31
Q

What virus can be used for gene therapy?

A

Adenovirus

32
Q

Rhinovirus Genome

A

(+)ssRNa

33
Q

Rhinovirus Virion

A

Non-enveloped

34
Q

Rhinovirus Incubation

A

1-4 days

35
Q

Rhinovirus Strains

A

over 100 different serotypes

Very large antigenic diversity

36
Q

Rhinovirus replication

A

Cytoplasm

Attaches to intercellular adhesion molecule 1 (ICAM-1) or the very low density lipoprotein (VLDL) receptor

37
Q

Rhinovirus Symptoms

A

Frequent cause of upper respiratory infection
Red nose (hyperemic)
Nasal discharge becomes mucorepelent (neutrophils)
Lasts 2-3 days with viable shedding - shedding can last up to 3 weeks

38
Q

Rhinovirus Transmission

A

Humans are the only known reservoir

39
Q

Rhinovirus Complications

A

Epithelial damage - likely due to the immune system

40
Q

Rhinovirus Treatment

A

No antivirals

41
Q

Rhinovirus Prevention

A

Because there are so many serotypes, vaccine development is impractical