Lecture 14 - Infection Prevention

Question 1

How can infections be spread?

Answer 1

From a non human source to humans
From person to person (directly or indirectly)

Question 2

What is an example of an environmental source of infection?

Answer 2

Legionella pneumophila

Question 3

What is an example of an infection from a food or water source?

Answer 3

Escherichia coli
Salmonella
Listeria (meningitidis)

Question 4

What is an example of an animal source of infection?

Answer 4

Rabies

Question 5

What are some examples of direct person to person infections?

Answer 5

Influenza
Norovirus
Neisseria gonorrhoea

Question 6

What are some examples of in-direct person to person infections?

Answer 6

Mosquitos infecting humans with Malaria

Question 7

What is endemic disease?

Answer 7

The usual background rate of disease that generally occurs in that area

Question 8

What is an outbreak?

Answer 8

When 2 or more cases are linked in time and place

Question 9

What is an epidemic?

Answer 9

When the rate of an infection is greater than the usual background rate

Question 10

What is a Pandemic?

Answer 10

When theres a very high rate of infection spreading across many regions, countries, continents

Question 11

What is the Basic Reproductive number (R0)?R number

Answer 11

The average number of cases that one case generates over the course of its infectious period in an otherwise uninflected non immune population

Question 12

What happens if the reproductive number (R0) = 1?
R0 = 1?

Answer 12

Stable number of cases

Question 13

What happens if R0 > 1?

Answer 13

Increase in the number of cases

Question 14

What happens if R0 < 1?

Answer 14

Decrease in the number of cases

Question 15

What is Legionella pneumophilla?

Answer 15

Gram negative bacteria
Lives in water

Question 16

How is Legionella pneumophila spread?

Answer 16

Inhaled via droplets from the environment
Not spread from person to person, from contaminated water source

Question 17

What is faecal oral transmission?

Answer 17

Ingestion of faecal matter

Question 18

How is norovirus transmitted?

Answer 18

Faecal oral transmission
Possibly airborne too

Question 19

What are the 4Ps?

Answer 19

4 reasons for outbreaks:
Patient
Pathogen
Practice
Place

Question 20

How may Pathogen factors cause outbreaks, epidemics or pandemics?

Answer 20

Antigens
Virulence factors
Antibacterial resistance

Question 21

How may Patient factors cause outbreaks, epidemics or pandemics?

Answer 21

New hosts due to people not being immune

Question 22

How may Practice factors cause outbreaks, epidemics or pandemics?

Answer 22

New things people may do

Question 23

What determines transmissibility of an infection?

Answer 23

Infectious dose (num of microbes needed to cause infection)

Question 24

What determines infectious dose?

Answer 24

Microorganism
Immunity of the potential host

Question 25

Describe the usual shape of an epidemic curve and why its like this?

Answer 25

Bell shaped curve Initially everybody is susceptible so number of people getting infected will keep increasing until a certain point From here less people are susceptible so less and less people get infected until the population has near enough fully recovered

Question 26

What is meant be stochastic nature?

Answer 26

Random Not a predictable

Question 27

What is the term used to describe the way that small scale outbreaks may occur?

Answer 27

Stochastic nature

Question 28

What can be done to prevent infection at the pathogen level?

Answer 28

Prevent the pathogen from entering a population ££

Question 29

What can be done at the patient level to prevent infection?

Answer 29

Improve general health of population Immunity (vaccinate)

Question 30

What can be done at the practice level to prevent infection?

Answer 30

Behaviour changes PPE

Question 31

What can be done at the place level to prevent infection?

Answer 31

Environmental engineering Separating sewage areas from drinking water areas

Question 32

How can pathogens and vectors be reduced/eradicated?

Answer 32

Antibacterial Decontamination Sterilisation Eliminate vector breeding sites

Question 33

How can we improve patients health?

Answer 33

Better nutrition Better medical treatment

Question 34

What is herd immunity?

Answer 34

Protection produced by most of the population being immune to a disease making person to person transmission very difficult This protects the non immune

Question 35

What practice interventions can be done to prevent infection?

Answer 35

Avoid a place/vector so dont go there Protective clothing PPE Safe sex Good food and drink prep

Question 36

What place interventions (environmental engineering) things can be done to prevent infection?

Answer 36

Safe water Safe air Good quality housing Well designed health care facilities

Question 37

What is good about controlling /preventing infections?

Answer 37

Decreased incidence or elimation of a disease/organism

Question 38

What is BAD about controlling /preventing infections?

Answer 38

Decreased exposure to pathogen Decreased immune stimulus Decreased frequency of antibody More susceptible individuals Can lead to outbreaks