Preventing Infections Flashcards
what is person to person indirect transmission
where a vector is required to transfer a disease between patients
what is an endemic disease
the rate of a disease that you would normally expect to see in a population for a specific organism
what is an outbreak
where there are 2 or more linked cases in a time and place
what is an epidemic
where the rate of infection is greater than the usual background rate
what is a pandemic
a world wide epidemic - a very high rate of infection across many countries
what is antigenic drift
when the influenza virus combines 2 or more different strains giving a mixture of antigens on its surface. Therefore more people are susceptible
what is antigenic shift
where mutation causes a new strain of a virus to be produced as a new antigen is produced meaning theres a loss of immunity as everyone is susceptible
what is the basic reproduction number
the average number of cases on case generates over the course of its infectious period in an otherwise uninfected population
what does it mean if R0>1
there is an increase in cases
what does it mean if R0=1
there is a stable number of cases
what does it mean if R0<1
there is a decrease in cases
what changes in a pathogen result in outbreaks of infection
new antigens (antigenic shift/drift), changes in virulence factors or antibacterial resistance
what changes in hosts result in outbreaks of infection
if the host is immunocompromised e.g. undergoing cancer treatment or HIV
what factor determines transmissibility
the infectious dose of a pathogen - different infections require different numbers of microbes in order to cause the infection
what is the shape of an endemic curve
bell shaped
what is the nature of a small scale outbreak
stochastic/ random
what interventions can be made on the 4 P’s to prevent infection
Pathogen - reduce vector/pathogen
Patient - improve health and immunity
Practice - protective equipment and behavioural changes
Place - environmental changes
how can you reduce/eradicate a pathogen
- antibacterial
- sterilisation
- decontamination
how can you reduce/eradicate vectors
eliminate the breeding sites
how can you improve a patients health and immunity
Health - nutrition and medical treatment
Immunity - passive though maternal antibodies and IV immunoglobin and active though vaccinations
what is herd immunity
vaccinating the majority of a population giving indirect protection to those who aren’t vaccinated as well as direct protection
what does the vaccination number for herd immunity depend on
the reproduction number for that infection
what environmental changes can be done to prevent infection
- safe water and air
- good quality housing
- healthcare facilities
what are the advantages of preventing infection
- decreased incidence
- elimination of disease/organism
