Week 139 - Communicable diseases III Flashcards Preview

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Flashcards in Week 139 - Communicable diseases III Deck (11):
1

Describe symptoms of flu

Incubation periof of ussually 2-3 days

Sudden onset

Usually resolves in 3-4 days

2

What are the complications of contracting flu?

Respiratory
- primary influenza pneumonia
- secondary bacterial pneumonia

Worsening of chronic conditions
- COPD
- Asthma
- Heart failure

Myocarditis

Pericarditis

Encepalopathy

GB-Syndrome

3

How can flu be transmitted?

Large respiratory droplets
- direct airborne
- indirect surface contamination (survive <= 24hours)

Virus sheddings
- detectable 24 hours before symptom onset
- most contagious first days of symptoms
- falls to low levels by day 5

4

What is flu?

Inflenza virus

- RNA virus

- contains 8 different genes that encode for neuraminidase (N) and haemaglutanin (H)

- strain defined by the type of H and N genes

5

What is antigenic drift?

RNA-dependent RNA polymerases have no proof reading mechanism

=> mistakes (mutations) are made during RNA synthesis

=> mutations are non-lethal and encode altered antigenic proteins

6

What is antigenic shift?

Infection of the same cell by two different flu types, often from species (i.e. bird and human)

Fragments from different flu types can be packed into a new virus with genes from both "parents"

7

What is an influenza pandemic and when does it occur?

An epidemic of influenza that spreads on a world wide scale

Occurs when a new influenza virus emerges as a result of antigenic shift, due to human population having no pre-existing immunity

8

When should anti-virals be used?

If all of the following occur:

- patient in an at risk group
- within 48 hours of flu-like symptoms occuring
- if influenza virus is circulating

9

Which people are considered at risk?

> 65 years old

Chronic conditions

Immunosuppressed

Pregnancy

10

Which patients should vaccinations be offered to?

At risk groups who are older than 6 months

11

When should antivirals be used as prophylaxis?

If all of the following apply:
- someone has "flu-like" symptoms likely caused by flu
- an at risk patient
- been in contact with patient with flu <48 hours