S5L2 - Infection Prevention Flashcards
(26 cards)
How are infections spread
From non-human source to humans
From person to person ( directly and indirectly)
What. Is a common source?
A source that passes on infection to many people, initiating a chain reaction.
Give 3 source examples
Environmental - Leginella pneumonphila ( causes legionnaires disease)
Food/water - food poisoning organisms, onward transmission possible
Animals - rabies, onwards transmission possible
What infections are transmitted by person to person direct contact?
Influenza
Nororvirus
Neisseria gonorrhoea
What infections are transmitted by person to person indirect transmission?
Malaria by mosquitos
What are the 4 consequences of transmission?
Endemic disease
Outbreak
Epidemic
Pandemic
What is an endemic disease?
The usual background rate of transmission
What is an outbreak of disease
Two or more cases linked in time and place
What is an epidemic
A rate of infection greater than the usual background rate
What is a pandemic?
Very high rate of infection spreading across many regions, countries and continents.
Reflects a strand that nobody is immune to
What does R0 mean?
The R0 is the average number of cases one case generates over the course of its infectious period in an otherwise uninfected , non-immune population.
The infectibility of a disease.
How does the R0 change?
If the number of cases increases, then the R0 >1
If the number of cases is stable then R0= 1 (endemic disease)
If there is a decrease in number then R0<1
What reasons are there for possible outbreaks/epidemics and pandemics?
New pathogen
New hosts
New practice (bringing pathogens and patients together)
What factors determine transmissibility?
The infectious dose. This is the number of microorganisms required to cause infection.
Varies by micro-organism, presentation of micro-organism and immunity of potential host)
What are epidemic curves?
A graph plotting number of people infected at each time interval (y) against time (X)
What shape is an epidemic curve?
Bell shaped.
As initially uninfected but susceptible, then infected, then recovered and immune.
What nature is displayed by small scale outbreaks on epidemic curves?
A stochastic nature (random)
What interventions can be used against the pathogen/vector ?
Reduction or eradication of pathogen - antibacterial including disinfectants - decontamination - sterilisation Reduce/eradicate of vector Eliminate vector breeding sites
What interventions can be used to stop patient transmission
Improve health - nutrition - medical treatment immunity - passive (maternal antibody, intravenous immunoglobin) - active (vaccination)
What interventions can be used against practice?
Behavioural change
- safe sex
- safe disposal of sharps
- food and drink preparation standards
Avoid pathogen or its vector
- Geographic
- Protective clothing/ equipment (long sleeves against mosquito bites)
- PPE in hospitals (gloves, gowns, masks)
What interventions can be used against place?
Environmental engineering
- safe water
- safe air
- Good quality housing
- well designed healthcare facilities
Describe herd immunity
When a small portion of the population is vaccinated, it can decrease the overall infection spread/R0 of the disease as less people will catch the disease and therefore wont be able to spread it forward.
What is a consequence of good intervention?
Decreased incidence or elimination of disease/organism (smallpox/polio/dracunculiasis)
What is a consequence of good intervention?
Decreased exposure to pathogen Decreased immune stimulus Decreased antibody Increased susceptibles Outbreak
