Epidemiology of infectious disease Flashcards
What is infectious disease epidemiology?
The study of spread, occurrence and control of disease within a defined population group
What is meant by the period of communicability?
When you are infectious to other people
What is infection?
Pathogen establishes itself in host
What is the latent period?
After the pathogen establishes itself but before it causes infection
What is incubation?
Period between infection and the onset of symptoms
What is disease?
When you develop symptoms
What is the difference between horizontal and vertical transmission?
Horizontal is spread in a non-parent - child relationship - it is direct.
Vertical is spread from the mother to the child e.g. via placenta, baby milk, during birth
What is direct transmission of disease?
Person to person spread or propagated
What is indirect transmission of disease?
Transmission via inanimate or animate means e.g. vectors, fomites and vehicles
Vectors like to feed on ______. They carry the infectious agent from one person to another
blood
What are fomites?
Inanimate objects e.g. bedding, surgical equipment
When they are contaminated, they can transfer the pathogen to the host
What are vehicles?
Non-living source of pathogens that infect large numbers of individuals e.g. food/water
Which type of transmission is a common sources of epidemics?
Indirect transmission
What are reservoirs?
Sites in which viable infectious agents normally reside, multiply in and rely upon for their survival. i.e. the natural habitat of the infectious disease - such as humans, animals
What is zoonosis?
When animals transmit infectious agents to humans
What is meant by human carriers?
An infected individual with no signs of disease
What is prevalence?
The proportion of diseased individuals in a population at any one time
What is incidence?
The number of cases or diseased individuals within a population
What is mortality?
Incidence of death within a population
What is morbidity?
Incidence of illness in a population (fatal or non-fatal)
What is meant by endemic?
persistent occurrence with a low to moderate level e.g. chickenpox
What is meant by epidemic?
Occurrence clearly in excess of the expected level for a given time period
What is meant by pandemic?
A worldwide spread of disease
What is sporadic level of incidence?
Occasional cases occurring at irregular intervals
What do epidemic curves tell us?
Mode of transmission
Timing of exposure
Course of exposure
What are the two main types of epidemic?
Common source
Propagated
What is a common source epidemic?
Object to person spread
What is the difference between common point source and common continuous source?
In common point source - exposure occurs in less than incubation period
In common continuous source - exposure occurs over multiple incubation periods
Common source epidemic curve shows a rapid increase in number of cases whereas propagated is more of a gradual increase. True or false?
True
Is propagated epidemic less than or greater than the incubation period?
Greater than
What is an example of continuous common source epidemic?
Cholera spread via contaminated water
What is an example of propagated epidemic?
Ebola
Influenza A
What are the public health interventions?
Vaccination
Infection control
Antivirals
