Session 10- Influenza and Virology Flashcards

1
Q

What is flu

A

An acute viral infection of the respiratory tract

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2
Q

Structure of the influenza virus

A

Orthomyxovirus are spherical, enveloped virus containing a segmented, negative strand RNA genome

2 surface antigens

  • haemagglutinin (H) - 18 types binds to cell of infected person
  • Neuraminidase (N) - 11 types - releases the virus from the host cell surface
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3
Q

Influenza A

A

Affects many animals undergoes antigenic drift and is responsible for pandemics

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4
Q

Influenza B

A

Only affects humans and undergoes antigenic drift- mainly affects older adults

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5
Q

Influenza c

A

Affects humans and pigs and undergoes antigenic drift and produces mild disease

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6
Q

How are influenza viruses transmitted

A

Person to person via the respiratory route- coughing, sneezing, inhaling

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7
Q

What are the first lines of defence in the innate immun system

A

1) respiratory epithelial cells are covered by a thick glycocalyx and tracheobronchial mucus that can trap viruses
2) ciliated respiratory epithelial cells continually sweep mucus up from the lower respiratory tract into the upper respiratory tract where it is swallowed
3) immunologic defences include secretatory IgA, natural killer cells and macrophages

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8
Q

How do viruses enter cells

A

They attach to sialic acid residues on host cell glycoproteins or glycolipids then entry via receptor-mediated endocytosis

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9
Q

What is attachment and fusion function associated with

A

Haemagglutinin protein

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10
Q

What is the viral release facilitated by

A

Neuraminidase protein which cleaves the sialic acid residue of the glycoprotein on the cell surface allowing release

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11
Q

Symptoms of i influenza

A
Fever 
Headache \
Sore throat 
Cough
Aches
Pains
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12
Q

Incubation time for influenza

A

5 days

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13
Q

Treatment of influenza

A

Antivirals
Neuraminidase inhibitors
Vaccination of vulnerable groups

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14
Q

What is genetic drift

A

Genome of the virus is constantly changing in small ways- point mutations- and this leads to genetic variation in both the surface antigens H and N

not as bad

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15
Q

What is antigenic shift

A

Major changes in the genes of flu viruses that occur suddenly when two or more different strains combine which results in a new subtype and is the
cause of widespread epidemics/pandemics

This refers to major changes in H and N proteins

VERY BAD

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