Infection Prevention Flashcards
How could an infection be transmitted indirectly from person to person? Given an example
Via a vector e.g mosquito - malaria
Give an example of a food/water transmissible infection
Food poisoning - EColi
Give an example of an environmentally transmitted infection
Legionaries
Give an example of person-to-person transmission
Influenza, Norovirus
Give an example of animal transmission
Rabies
Define endemic disease, outbreak, epidemic, pandemic
Endemic - normal background rate of disease
Outbreak - two or more new cases linked in time and place
Epidemic - A rate of infection greater than the usual background rate
Pandemic - Very high rate of infection spreading across many regions/countries/continents
What is R0? High R0? Low R0? At what R0 would an infection outbreak self terminate?
R0 is the average number of cases one case generates over the course of it’s infectious period, in an otherwise uninfected, non-immune population. Higher R0 = increase in cases, Below R0 - 1 is a decrease in cases. Below 1 an outbreak will self-terminate
What are the 4 Ps of infection spread?
Pathogen
Patient
Place
Practice
How can a pathogen change cause an outbreak/epidemic/pandemic (3)?
- Change in virulence factors
- Change in antigens
- Antibacterial resistance (mutation)
How can patients (hosts) cause outbreaks?
Non-immunes - e.g. immunosuppressed, healthcare effects e.g. HAI outbreaks
How can practice cause outbreaks?
New practices
Define infectious dose. What can affect the infectious dose?
Number of organisms required to cause infection. Can change with person (immunity), presentation (how infected), and different microorganisms have different infection doses
Give an example of an organism that requires a high infectious dose, and a low one
High - Salmonella
Low - E Coli
What does a typical epidemic curve look like?
A bell curve
How can you use the 4Ps to intervene and control infection outbreaks?
Pathogen - reduce/eradicate pathogen/vector - e.g. antibacterial, sterilisation
Patient - improved health and immunity
Place - environmental engineering e.g. cleanliness/safe water/well designed healthcare facilities
Practice (behaviour)- protective equipment, change behaviour e.g. aseptic technique, don’t go to a country, wear long sleeves to prevent mosquitos
How does sterilisation reduce infection?
Removes pathogen
How can you improve someones immunity to an infection?
Vaccination
What is herd immunity? Is it the same for all infections or do some require increased immunity to prevent spread?
Herd immunity is where resistance to spread of a disease in a population (mostly through vaccination) results in a sufficiently high proportion of people that are immune to stop the spread of disease. The % vaccinated to achieve this is different depending on the disease e.g. measles highly contagious need high her immunity, flu less so.
What are some positive and negative consequences of infection control?
Positive - reduced outbreaks/elimination e.g. small pox
Negative - reduced immunity as reduced exposure –> decreased antibodies –> leads to outbreak
What is legionnaires disease?
Atypical type of pneumonia caused by legionella pneumoniae
