Lecture 1 Notes Flashcards
Avian flu
A severe, often fatal flu virus of birds, especially poultry, that is transmissible from them to humans
-aka = bird flu
What happens as more vaccines are introduced?
The mortality rate decreases
When was the Spanish flu?
1918
Spanish flu
Influenza caused by an influenza virus of type A
Smallpox
An acute contagious viral disease, with fever and pustules usually leaving permanent scars
What are the 4 definitions of epidemiology
- Friedman, 1987 = Study of disease occurrence in human populations
- Schulte, 1993 = Study, prevention and control of health risks faced by human populations
- Madigan, 2003 = Study of the occurrence, distribution and control of diseases
- Tortora, 2013 = Science that studies when and where diseases occur and how they are transmitted in populations
What is epidemiology? (5)
- Systematic collection and analysis of vital statistics
- Delineation of the triad of agent, host and vector
- Refined exposure assessment
- Clearly delineated study designs
- Increase conceptional and statistical capabilities for modelling diseases and predicting epidemics or pandemics
What are the 3 types of epidemiology?
- Descriptive
- Analytical
- Experimental
Descriptive epidemiology
Collecting data and describing occurrence of human diseases
Analytical epidemiology
Analyzing a particular disease using case control method or cohort method
Experimental epidemiology
Tests effectiveness of a new vaccine against AIDs
What are the 8 causes of death and their %?
- Communicable diseases (32%)
- lower respiratory tract = 6.8%
- HIV/AIDs = 4.9%
- diarrheal diseases = 3.2%
- tuberculosis = 2.7%
- malaria = 2.2%
- measles = 1.1% - Non-communicable diseases (58%)
- cardiovascular diseases = 29.3%
- cancer = 12.5% - Injuries (9%)
What does the triad consist of? (3)
- Agent
- Host
- Vector
Agent
Is the cause of the disease
- typically a microbe = too small to see with the naked eye
What are 5 examples of an agent?
- Bacteria (gonorrhea)
- Protozoa (malaria)
- Virus (influenza)
- Prions
- Chemicals
Host
An animal or a plant in which a parasite or commensal organism lives
What are 4 examples of a host?
- Humans (culture, geography, history)
- Animals (vertebrate, invertebrate)
- Plants (gymnosperm)
- Bacteria
Vector
An organism which transmits infection by conveying the pathogen from one host to another without causing disease itself
What are 4 examples of vectors?
- Ticks (Lyme disease)
- Mosquitos (malaria)
- Needles
- Surgical devices
What are the 2 population models?
- Exponential
2. Logistic
What is the formula for the exponential model?
dN/dt = rN r = growth rate
What is an example of exponential growth rate?
E. coli
- reproduce every 20 mins
What is the formula for the logistic model?
dN/dt = rN(1-N/K)
What is an example of logistic model?
tick/mosquito
- reproduces > days
What are 5 ways to detect and agent?
- PCR
- Microarray
- Elisa
- Epi-fluorescence
- Microscopy
What are the 2 factors that affect distribution of vectors?
- Geography
2. Culture
Fomites
Objects or materials that are likely to carry infection
What are 5 examples of fomites?
- Needles
- Surgical devices
- Clothes
- Utensils
- Furniture
What is the goal of epidemiology?
To prevent and control health risks faced by the human population
What are 2 ways to control transmission of infectious diseases at the host level?
- Vaccines and toxoids
2. Antibiotics
What are 3 ways to control transmission of infectious diseases at the environmental level?
- Control the vector b insecticide
- Hygienic procedures
- Emerging field
What is an example of an environmental prevention?
DDT
- used to control infection from mosquitos
- had a massive impact on the environment
- need to look at the impact on the environment when coming up with a cure
What does epidemiology provide? (3)
- More accurate comparisons among groups
- agents, hosts and vectors - Further classification of mechanisms
- More specialized assessment of individual risks
Traditional epidemiology (1 step)
Exposure –> disease
Molecular epidemiology ( 5 steps)
Exposure –> internal dose –> effective dose –> altered structure/ function –> clinical disease –> prognostic/ significance
Biomarkers
a measurable substance in an organism whose presence is indicative of some phenomenon such as disease, infection, or environmental exposure
What do valid biomarkers provide? (7)
- The precise continuum of events
- Identification of exposure to lower doses
- Early identification of events in clinical disease
- Reduction of misclassification of dependent and independent variables
- Indication of mechanism relating exposure to disease
- Better accounting for variability (agent and host)
- Enhance individual and group assessment
What are dependent variables?
Something you cant control
What is an example of a dependent variable?
Tree growth
What is an independent variable?
Something you can control
What is an example of an independent variable?
Exposure of moisture for trees
What do molecular tools allow?
Early identification to resolve population issues
–> prevention
What are 2 levels of molecular epidemiology for population?
- Behaviour
2. Environment
What are 2 levels of molecular epidemiology for organisms?
- Specific exposure
2. Systemic communication
What are 3 levels of molecular epidemiology for cells?
- Cell-cell communication
- Substrate molecules
- Genetic instructions
Influenza virus
an acute and infectious disease of the respiratory system caused by a virus and characterized by fever, muscle pain, headache, and inflammation of the mucous membranes in the respiratory tract
How many strands does an RNA virus have?
single strand
Hemagglutinin
refers to a substance that causes red blood cells to clump together
Neuraminidase
an enzyme, present in many pathogenic or symbiotic microorganisms, that catalyzes the breakdown of glycosides containing neuraminic acid
What is a key factor in immune response?
Proteins
Pandemic
Prevalent of a disease over a whole country or the world
- larger scale (compared to an epidemic)
When was the last influenza outburst?
1968
