Intro To Epidemiology Flashcards
What is Microbiology definition
Study of microorganisms
What is the definition of microorganisms/ microbes
Microscopic organisms
Definition of a pathogen
Microorganisms that CAN cause disease
Are pathogens only found in humans
No, not necessarily
Definition of infectious disease
Caused by pathogenic microorganisms which can be spread, directly or indirectly from one person to another
Definition of medical Microbiology
The study of microorganisms that are of medical importance and susceptible of causing disease in human beings
What is an infectious disease
Caused by an infectious agent
Give an example of an infectious disease
Tetanus
What is the definition of a communicable disease
Transmission - directly or indirectly from an infected person eg. Food poisoning
Give an example of a communicable disease
Measles
Definition of a transmissable disease
Transmission- through an unnatural route - from an infected person
Eg. Prior disease through needles
Example of a transmissable disease
vCJD
What are the possible ways of DIRECT routes of transmission
Skin to skin
Mucous to mucous
Across placenta
Through breast milk
Sneeze - cough
Give a disease that’s transmitted through skin to skin
Herpes type 1
Give a disease transmitted by mucous to mucous
STIs
Give a disease that’s transmitted across the placenta (mother and born baby)
Toxoplasmosis
Give a disease transmitted through breast milk
HIV
Give a disease transmitted through sneeze/ cough
Influenza
List all the INDIRECT modes of transmission
Food borne
Water borne
Vector borne
Air borne
Name a food borne disease
Salmonella
Name a water borne disease
Hepatitis A
Name a vector borne disease
Malaria
Name an airborne disease
Chicken pox
Can DNA AND RNA viruses cross the placenta
Yes
Name action modes of direct contact disease transmission
Hand shaking
Kissing
Sex
Bites
Name action modes of indirect contact disease transmission
Drinking glasses
Toothbrushes
Toys
Punctures
Droplets from sneezing and coughing (within one meter)
Name airborne methods vehicle disease transmission
Dust particles
Name waterborne methods vehicle disease transmission
Streams
Swimming pools
Name foodborne methods vehicle disease transmission
Poultry
Seafood
Mec
Modes of transmission - how many types of vector transmission and what are they
- Mechanical - on insect bodies, flies and roaches
- Biological - lice, mites, mosquitos and ticks
How many types of vehicle transmission and what are they
1.airborne
2.waterborne
3.foodborne
How many types of contact transmission and what are they
- Direct transmisson
- Indirect transmission
Toxoplasmosis can be contracted from which animal and their what
Cats and their poo
What food can listeria be contracted from
Hummus
What are the 4 outcomes of exposure to an infectious agent
No infection
Clinical
Sub clinical
Carrier
What are the 4 outcomes of being clinical after exposure to infectious agents
Death
Carrier
Immunity
No immunity
What are the 3 outcomes of being sub clinical after exposure to infectious agents
Carrier
Immunity
No immunity
In the time line of infection what are the 3 stages after infection
Incubation period
Symptomatic period
Non diseased
With regards to transmission, what does index mean
The first case identified
With regards to transmission what does primary case mean
The case that brings the infection into a population
What is patient zero known as
Index
How do you calculate attack rate
Attack rate = ill ÷ exposed
What does an attack rate of 80% mean
Means that 80% of the people exposed show disease
What 3 things does the epidemiologic triad involve and what does it mean
Shows disease is the result of forces within a dynamic system consisting of:
Agent
environment
Host
And disease in the middle of triangle going to disease
These are factors that impact disease transmission
In the epidemiologic triad, what are the factors influencing disease transmission as part of AGENT
Infectivity
Pathogenicity
Virulence
Immunogenicity
Antigen stability
Survival
In the epidemiologic triad, what are the factors influencing disease transmission as part of HOST
Age
Sex
Phenotype
Behaviour - how healthy/ well fed?
Nutritional status
Health status
In the epidemiologic triad, what are the factors influencing disease transmission as part of ENVIRONMENT
Weather - hospital setting, damp environment, poor housing…
Housing
Geography
Occupational setting
Air quality
Food
Equation for infectivity- ability to infect
Number infected/ number susceptible x 100
Equation for pathogenicity- ability to cause didisease
Number with clinical diease/ number infected x 100
Equation for virulence- ability to cause death
Number of deaths/ number with disease x 100
What is virulence
Ability to cause deaths
What are infectivity, pathogenicity and virulence all dependent on
All are dependent on host factors
Summarise important concept of kochs postulates to identify the microbial cause of specific diseases
Microbe must be present in every case of the disease but not in healthy organisms
Microbe must be isolated from a disease host and grown in pure culture
Disease must be reproduced when a pure culture is introduced into a non disease susceptible host
Microbe must be recoverable from an experimentally infected host
Compare endemic epidemic and pandemic
Endemic- transmission occur, but the number of cases remains constant within a certain area
Epidemic: a rapid increase in the numbers of cases in a certain area
Pandemic: when epidemics spread and occur at several continents- a global epidemic
