S5 L2 - Infections Prevention, C.diff

Question 1

Endemic disease
Outbreak
Epidermic
Pandermic

Answer 1

Endemic disease: The usual background rate

Outbreak: Two or more cases linked in time and place

Epidermic: A rate of infection greater than the usual background rate

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

Question 2

Basic reproduction number

Answer 2

Basic reproduction:
• Ro - the average number of cases one case generates over the course of its infectious period, in an otherwise uninfected, nonimmune population
• If Ro >1 increase in cases
• If Ro =1 stable number of cases
• If Ro <1 decrease in cases

Question 3

• *Reason for outbreak, epidermics, pandemics**
• Pathogen (from the 4P’s)
• Patient (from the 4P’s)
• Practice (from the 4P’s)

Answer 3

Pathogen -
New pathogens or changes in antigens

Patient - 
New hosts (babies not been vaccinated yet)

Practice -
e.g. gay bars increase this rates of HIV

Question 4

• *Interventions**
• 4 P’s and briefly how interventions could be put in place for these

Answer 4

4 P’s and briefly how interventions could be put in place for these:

Question 5

• *Interventions:**
• Pathogens and vector
• Patient

Answer 5

Pathogens and vectors:
• Reduce/eradicate pathogen:
- Antibacterials including disinfectants
- Decontamination
- Sterilisation
• Reduce/eradicate vector -
Eliminate vector breeding sites

Patients:
• Improved health
- nutrition
- medical treatment
• Immunity
- Passive e.g. maternal antibody, intravenous immunoglobulin
- Active i.e. vaccination

Question 6

• *Interventions:**
• Practice
• Place

Answer 6

Practice:
Avoidance of pathogen or its vector:
- Geographic, “Don’t go there”
- Protective clothing, equipment PPE:
- long sleeves, trousers against mosquito bites
- Personal protective equipment in hospitals –> gowns, gloves, masks
- Behavioural:
•Safe sex •Safe disposal of sharps •Food and drink preparation

Place:
•Environmental engineering:
- Safe water
- Safe air
- Good quality housing
- Well designed healthcare facilities

Question 7

Herd Immunity

Answer 7

Question 8

• *Consequences of control**
• Good consequences
• Bad consequences

Answer 8

GOOD
• Decreased incidence or elimination of disease/organism
e.g. Smallpox

BAD
• Decreased exposure to pathogen -> decreased immune stimulus -> decreased antibody -> increased susceptibles -> outbreak
• Later average age of exposure -> increased severity
e.g. Chicken pox

Question 9

• *Clostridioides difficile**
• Pathogen
• Patient
• Mechanism of infection
• Symptoms
• Virulence factors
• Diagnosis
• Treatment
• Outcome

Answer 9