Infection Prevention

Question 1

What is the communicable nature of infections ?

Answer 1

1. From a non human source to humans

2. From person to person ( direct or indirect)

Question 2

What are the 4 consequences of transmission ?(

Answer 2

1. Endemic disease
2. Outbreak
3. Epidemic
4. Pandemic

Question 3

What is an endemic disease ?

Answer 3

The usual background rate of infection - an .innfection that is going on all the time

Question 4

What is an outbreak

Answer 4

Two or more cases linked in time and place

Question 5

What is an epidemic

Answer 5

The rate of infection greater than the usual background rate

Question 6

What is a pandemic

Answer 6

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

VERY ABNORMAL eg swine flu.

Question 7

What is R0 ( reproductive. Number) is

Answer 7

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

For example if one person was infected and infected 11 other people the R0 would be 11.

Question 8

If R0 is greater than 1 , what does this suggest ?

Answer 8

There is an increase in cases

Question 9

If R0 = 1 , what does this suggest?

Answer 9

Stable number of cases

Question 10

If R0 is lower than 1 , what does this suggest ?

Answer 10

Decrease in cases so the disease is likely to die out

Question 11

Reasons for outbreaks , epidemics, pandemic

Answer 11

1. New pathogen ( different antigen , virulence factors , antibacterial resistance) which infects the patient.
2. New hosts ( changes in people - for example children not being vaccinated when born , last few weeks of gestation antibiotics given to mother to be transmitted to child but as they grow up they lose immunity)
3. New practices ( social ‘

Question 12

How to intervene with pathogens and vectors ?

Answer 12

• eradicate or reduce pathogen

Using antibacterials incl disinfectants.

• reduce / eradicate vectors by eliminating vector breeding sites.

Question 13

How to intervene with patients ?

Answer 13

1. Improved health through nutrition, medical treatment

2. Immunity : passive ( maternal antibody) active :( vaccination )

Question 14

What is herd. Immunity

Answer 14

Not everyone in a community needs to be vaccinated in order to prevent the spread of a disease. If a high enough proportion of individuals in a population are immune , the majority will protect the few susceptible because the pathogen is less likely to find a susceptible person.

Question 15

What level of vaccinations do you need to provide herd immunity ?

Answer 15

• depends on the disease
• depends on the reproductive number

For example for measles , we need 95% of population to be vaccinated in order to achieve herd immunity.

Question 16

How to intervene in practice to prevent infection ?

Answer 16

1. Avoidance of pathogen or vector eg geographic. Or if you do go , wear protective clothing / equipment eg mosquito netting.
2. Safe sex , safe disposal of sharps , food and drink preparation.

Question 17

Interventions - place

Answer 17

Safe water

Safe air

Good quality housing

Well designed healthcare facilities

Question 18

What are the good consequences of control ?

Answer 18

Decreased incidence or elimination of disease. For example small pox is completely eradicated.

Question 19

What are the bad consequences of control ?

Answer 19

Decreased exposure to pathogen means there is decreased immune stimulus which means there is decreased antibodies. Which means that there is an increased susceptibles which leads to a potential outbreak.