12 - Infection Prevention Flashcards
Explain the three different ways in which infections can be transmitted
Define the following terms:
- Endemic Disease
- Outbreak
- Epidemic
- Pandemic
- Endemic: usual background rate
- Outbreak: two or more cases linked in time and place ((plausible in terms of infection dynamics – incubation period,strains)
- Epidemic: Rate of infection greater than usual background rate
- Pandemic: very high rate of infection spreading across many regions, countries etc
What is basic reproduction number (R0) and what is its significance?
What are some reasons for outbreaks, epidemics and pandemics?
- New pathogens: antigens, virulence factors, antibacterial resistance
- New hosts: non-immunes, healthcare effects
- New practice: social, healthcare
What is an infectious dose?
Number of microorganisms required to cause infection, varies on micro-organism, presentation of micro-organism and immunity of potential host
What is the infectious dose of salmonella?
Quite high >105, therefore harder
What is an epidemic curve?
During outbreaks a graph representing the number of people infected at each time interval
Outline the four P’s of infection prevention for outbreaks.
What interventions are aimed at pathogens/vector to prevent infection?
- Reduce/eradicate pathogen: antibacterials/disinfectants, decontamination, sterilisation
- Reduce/eradicate vector: eliminate vector breeding sites
What interventions are aimed at patients to prevent infection?
- Improved health: nutrition, medical treatment
- Immunity: vaccinations, mother’s antibodies
What is herd immunity?
What is antigenic shift and antigenic drift?
Shift, everyone is susceptible
What interventions are aimed at practice to prevent infection?
- Avoiding pathogen or vector, e.g avoid visiting certain places
- Protective clothing/equipment, e.g PPE and long clothes for mosquitos
- Behavioural, e.g safe sex, sharps bins, food and drink prep
What interventions are aimed at place to prevent infection?
Environmental engineering
- Safe water
- Safe air
- Good quality housing and healthcare facilities
What are the positives and negatives of infection prevention measures?
Positive:
- decreased incidence or elimination of disease, e.g polio, small pox, dracunculiasis
Negative:
- decrease exposure to pathogen --> decreased immune stimulus –> decreased antibody –> increased susceptibilit and outbreak
- Later age of exposure so increased severity, e.g chicken pox, Hep A, Rubella
What would the epidemic curve look like for norovirus on a ward?
Hard to tell, random, can be cyclical in seasons
