Session 8 - Infection prevention Flashcards Preview

Semester 3 - Infection > Session 8 - Infection prevention > Flashcards

Flashcards in Session 8 - Infection prevention Deck (32)
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1
Q

Give three different mechanisms of infection

A
  • Common source
    • Person-to-person direct
    • Person-to-person indirect
2
Q

Give three examples of common sources and the infections associated

A
  • Food/water - Food poisoning organisms
    • Environmental - Legionella Pneumophilia
    • Animals - Rabies
3
Q

Give three examples of person to person direct infection

A
  • Influenza
    • Norovirus
    • Neisseria Gonnorhoeae
4
Q

Give three examples of person to person indirect transmission (involved a vector)

A
  • Mosquitos - Malaria, dengue
    • Cats - Toxoplasmosis
    • Ticks - Lyme disease, spotted fever
5
Q

What is an endemic disease?

A

• The usual background rate

6
Q

What is an outbreak?

A

• Two or more cases linked in time and place

7
Q

What is an epidemic?

A

A rate of infection greater than the usual background rate

8
Q

What is a pandemic?

A

Very high rate of infection spreading across many regions, countries and continents

9
Q

What is a basic reproduction number?

A

The average number of cases one case generates over the course of its infectious period, in an otheriwse uninfected, non-immune population

10
Q

What if Ro>1?

A

Increase in cases

11
Q

If Ro=1?

A

• Stable number of cases

12
Q

What if Ro <1?

A

• Decrease in cases

13
Q

Give three reasons for outbreaks

A
  • New pathogen
    • New hosts (compromised immunity, healthcare effects)

New practice

14
Q

What is an infectious dose?

A

Number of micro-organims required to cause infection

15
Q

Give an organism with a high infectious dose

A

• Salmonella - Requires >10^5 organisms

16
Q

Give an organism with a low infectious dose

A

• Escherichia coli - Very low <10 organisms

17
Q

Give three factors which vary the necessary infectious dose

A
  • Micro-organism
    • Presentation of micro-organism
    • Immunity of potential host
18
Q

What are the four P’s of infection?

A
  • Pathogen
    • Patient
    • Practice
    • Place
19
Q

How do you reduce outbreaks due to pathogens?

A
• Reduce/eradicate pathogen
		○ Antibacterials including disinfectants
		○ Decontamination
		○ Sterilisation
	• Reduce/eradicate vector 
		○ Eliminate vector breeding sites
20
Q

How do you reduce outbreaks due to patients?

A
• Improved health immunity
		○ Passive 
		○ Active
	• Improved health
		○ Nutrition
		○ Medical treatment
21
Q

What is passive immunity?

A

Passage of maternal antibodies across placenta

22
Q

Why does the incidence of meningitis increase dramatically at three months after birth

A

• Newborns have immunity from mothers antibodies up to that point

23
Q

How do you reduce outbreaks due to practice?

A

• Behavioural change

24
Q

How do you reduce infections due to place?

A
  • Environmental

* Engineering

25
Q

What is herd immunity?

A

• If 90-95% population vaccinated, gives protection to those who are not as pathogen has no vector

26
Q

Give two categories of changes in practice which will protect infection?

A
  • Avoidance of pathogen or its vector

* Behavioural

27
Q

Give two main methods of avoiding pathogens or vector as a change in practice to prevent infection

A
  • Geographic (Don’t go there!)

* Protective clothing, equipment

28
Q

Give three big behavioural changes which prevent infection

A
  • Safe sex
    • Safe disposal of sharps
    • Food and drink preparation
29
Q

Give an example of how place can be modified to prevent infection

A
  • Safe water
    • Safe air
    • Good quality housing
    • Well designed healthcare facilities
30
Q

What are the good consequences of increased control of bacteria?

A

• Decreased incidence or elimnation of disease/organism

31
Q

What are the negative consequences of increased contorol of bacteria?

A

• Decreased exposure to pathogen -> Decreased immune stimulus -> Decreased antibody -> Increased susceptibility -> Outbreak (polio, decreased exposure when young means bad when old)

Later average ages of exposure -> Increased severity

32
Q

What is congenital rubella virus?

A

If infected in first 12-14 weeks of pregnancy will suffer from abnormal development