Infection Prevention Flashcards
Name the methods by which infections can spread
Contiguous (direct) Inoculation Haematogenous Ingestion Inhalation Vector Vertical
Define endemic disease
The usual background rate
Define outbreak
2 or more cases linked in time and place
Define epidemic
Rate of infect greater than usual background rate
Define pandemic
Very high rate of infect, spreading across many regions
What is the basic reproduction number?
R0 = average case number one case generates over the course of its infectious period – in an otherwise uninfected, non-immune pop (R0 = 1 = stable caseload)
What is antigenic drift?
Mechanism for variation in viruses that involves the accum of mutations within the genes that code an Ab-binding sites
What is antigenic shift?
This is when we see pandemics – process by which >2 diff strains of a virus combine to form a new subtype, mixing surface antigens
What is the ‘infectious dose’?
Number of MO required to cause infection
Why do we get outbreaks, endemics, pandemics?
New pathogen, virulence factors, Ab resistance, non-immune pop, healthcare effects, new social practices
What is herd immunity?
Form of immunity that occurs when a significant portion of a pop provides a measure of protection for individuals who have not developed immunity
Outline the principles of infection prevention
Pathogen: reduction, eradication (antibact, decontamination, sterilisation, eliminate vector breeding sites).
Pt: improved heath (nutrition, med treatment), immunity (passive, active).
Practice: behavioural (safety), change (don’t go there), protective, equipment.
Place: environmental engineering (safe water, air, housing)
Discuss good consequences of disease control
Decreased incidence, elimination
Discuss bad consequences of disease control
Decreased exposure = decreased immune stim = decreased Ab = increased susceptibles = outbreak. Later average age of exposure – increased severity
