Influenza - Zeng Flashcards Preview

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Flashcards in Influenza - Zeng Deck (31)
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1
Q

Influenza contains lipid envelope containing what 2 viral membrane proteins

A

Hemagglutintin ( HA)

Neuroaminidase ( NA)

2
Q

What does the nucleocore contain

A

8-RNA segment
Nuclear matrix protein (M1)
nucleoprotein (NP)

3
Q

What are the 3 types of influenza

A

A B C

4
Q

What is influenza classification based on

A
  • serologic cross-reactivity

- sequence similarity of M1 and NP

5
Q

Which influenza type is considered harmful to humans

A

A and B

- C can cause disease in human but not serious human health concern

6
Q

What are the subtypes in influenza type A

A

based on HA and NA

7
Q

What are influenza type A have caused extensive outbreaks in humans

A

HA 1, 2, 3
NA 1, 2

H1N1
H3N2

8
Q

What is antigenic drift? what types does it occur in? what does it cause?

A
  • point mutations in HA and NA
  • A and B
  • epidemic infuenza
  • occurs gradually
9
Q

What is antigenic shift? what types does it occur in? what does it cause?

A
  • reassortment of genomic RNA segments
  • A only
  • pandemic influenza
  • sudden changes in HA andNA
10
Q

When does flu most commonly occur? and why at this time?

A

winter and early spring
December to March
- low temp and low humidity

11
Q

What are 2 routes of transmission for flue

A

airborne droplets

contaminated surfaces

12
Q

how does flu interact with human cell

A

HA and sialic acids

13
Q

what is human receptor preference

A

alpha 2,6 linked sailic acids

alpha 2,3 linked sailic acid

14
Q

Where is alpha, 2,6 found in humans

A
tracheobronchial epithelium ( upper and lower tracts)
type I pneumocytes
15
Q

Where is alpha, 2,3 found in humans

A

distal bronchiole epithelium

type II pneumocytes

16
Q

What is a reservoir for all A subtypes

A

Avian

- rarely infect humans directly

17
Q

who does swine impact? what happens

A

humans and birds

- ‘mixing vessels’ for reassortment between avian and human viruses

18
Q

How does HA influence viral infectivity

A
  • cleavage of HA
  • single basic amino acid cleavage
    • extracellular cleavage only
    • systemic viral replication
  • multiple basic amino acid cleavage
    • intracellular proteases
    • viral replication
19
Q

How does NA influence viral infectivity

A
  • cleavage of sialic acids from glycoprotein
  • release virions from infected cells
  • prevent viral aggregation in extracellular space to enhance viral disemination
20
Q

what are systemic clinical features of flu

A
fever
malaise
headache
myalgia 
no viremia
21
Q

what are respiratory clinical features of flu

A

dry cough
sore throat
nasal congestion/clear discharge

22
Q

what is a complication of flu in children

A

otitis media

23
Q

what are other complication of flu in children

A

sinusitis

primary viral pneumonia

24
Q

what are secondary bacterial pneumonia

A

step pneumo
S . aureus
H. flu

25
Q

what is Reye’s syndrome

A

aspirin to fever children

26
Q

what is reye’s syndrome

A

acute encephalopathy
fatty liver degeneration
rashes and vomiting
potentially lethal

27
Q

What is used to treat flu A? MOA?

A

Amantadine and Rimantadine

-M2 inhibitors ( inhibits viral uncoating, replication)

28
Q

What is used to treat flu A and B? MOA?

A

Oseltamivir and Zanamivir

  • NA inhibitor
  • reduces risk for pneumonia
29
Q

complications/ SA of vaccination

A
  • allergy to egg antigens

- Guillain-Barre syndrome

30
Q

what is guillian-barre syndrome

A

polyneuritis

- muscle weakness and paralysis

31
Q

what are 3 types of vaccines

A
  1. formalin
  2. Detergent
  3. Purified viral glycoprotein