Chapter 36- Influenza Flashcards Preview

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Flashcards in Chapter 36- Influenza Deck (14):
1

The 4 characteristics of the virus

Segmented, negative sense enveloped single stranded RNA

2

The two envelope spikes

Hemagglutinin (HA) & Neuraminidase (NA)

3

Hemagglutinin (HA)

Binds to silica acid on epithelial cells. fusion of the envelope.

4

Neuraminidase (NA)

Cleaves sialic acid

5

Influenza A is named by:

place of isolation, date of isolation, antigen (HA & NA), and epidemics and pandemics

6

Influenza B named by

type, geography, date, sometimes epidemics

7

Influenza C named by

mild respiratory illness, no epidemics

8

Antigenic drift

minor mutations that lead to small changes that make the previous immune response less effective.

9

Antigenic shift

More dramatic changes. occur less often

10

Influenza A diversity

Antigenic shift can occur because the virus can infect many animal species.

11

Local and systemic effects of Influenza A

Local: due to cell changed (mucus secretions; epithelial damage)
Systemic: due to immune response (interferon)

12

Diagnosis

Rapid Ag testing- nasopharyngeal specimen usually the best.

13

How do neuraminidase inhibitors work?

block the function of viral neuraminidases of influenza by preventing it from budding from the cell.

14

The three types of vaccines

1) Inactivated- 3 to 4 inactivated influenza vaccine. grown in egg, purified and inactivated with formalin
2) Live, attenuated intranasal- cold adapted
3) Recombinant- recombinant and egg free