General Principles of Infectious Disease Epidemiology and Control Flashcards
Define Epidemiology
The study of the distribution and determinants of health related conditions in populations and how it is applied to the control of health problems
How do we calculate the prevalence of an infectious disease
number of infected/100,00
How do we calculate the incidence of an infectious disease
(# of infected/100,00)/ per annum
Prevalence/per annum
How do we calculate the standard mortality rate due to an infectious disease
(# of deaths/100,00)/per annum
Define R0
This is also known as the reproductive index which signifies the contagiousness or transmissibility of an infective agent.
When R0 < 1 its low
When R0 > 1 it is high
What is viral shedding?
This is the release of a viral illness from an infected person’s body into the environment by sneezing, coughing or speaking
What are the four steps in infection control?
- Data collection and quality
- Description of Infection
- Analysis of Infection
- Predictions and Planning
What are 5 sources of data collection in epidemiology
- Lab reports
- Clinical reports
- Death reports
- Surveillance
- Investigation
Why is the quality of data important and why would data from these sources be inaccurate?
The numbers may not always be accurate. From death certificates for example the death may not be caused by the infection being analyzed, additionally not all deaths come with a postmortem and the cause of death may not be known
Additionally with investigation, not everyone would be comfortable with health officials coming into their homes and conducting a thorough investigation
What are the three categories of description epidemiologists give to infections
- Definite
- Probable
- Possible/Suspected
Suspected infections come about from
no samples, they tend to be secondary infection after being in contact with a confirmed case
Probable infections are determined from
an indeterminate sources, the infection tends to be contracted in the hospital
Definite infections are determined from
A positive sample/source/case
Infections abide by the ‘equation’ below
Index case —–transmission——> Susceptible
The infection can be interrupted at any point.
What three ways can the index case be interrupted?
Prioritizing
- Case definition
- Effective treatment
- Isolation
Infections abide by the ‘equation’ below
Index case —–transmission——> Susceptible
The infection can be interrupted at any point.
What three ways can the transmission be interrupted?
Prioritize
- Understanding transmission routes
- Understanding how to control these transmission routes
