Definitions
Surveillance
Prevalence vs Incidence
Testing
Sensitivity vs Specificity
100
What is Health?
In people (a condition) mind, body and spirit, usually meaning to be free from illness, injury or pain
100
What is Disease Prevalence and what is its equation?
Total number of cases of the risk factor in a specific time, divided by the total number of individuals.
(indicates how widespread the disease is)
Prevalence = (diseased) / (diseased + healthy)
100
What are the two different types of tests?
- Clinical (visual) examination
- Diagnostic and screening tests
100
Can a test be 100% sensitive and specific at the same time?
NO
200
What is Disease?
A finite abnormality of structure or function with an identifiable pathological or clinical pathological basis, and with a recognizable syndrome of clinical signs
200
What is the importance of epidemiological surveillance? (3)
Helps with the application of,
- prevention
- control of disease/outbreaks
- management
200
What is disease incidence and what is its equation?
The number of new cases of a disease in a given population at a specific time
(risk of contracting the disease)
Incidence = new cases / total population
200
What is the most accurate type of screening?
Mass screening (test everyone)
200
What does the testing matrix look like?
300
What is Morbidity vs Mortality
Morbidity: a condition of being diseased
Mortality: 1) the quality of being mortal. 2) death as statistic
aka morbidity (diseased) is not mortality (death)
300
According to the CDC a good surveillance program should be?
- Simple
- Flexible
- Sensitive
- Specific
- Time sensitive
- Representative
- Acceptable
- Stable
300
Poultry unit consisting of 10000 layer hens. Initial tests indicated 4500 layer hens had osteoporosis (thin bones). The ration was changed and 3 weeks later 8000 birds were shown to have thin bones .
What is the prevalence osteoporosis on the first testing day?
Prevalence = (diseased) / (diseased + healthy)
Prevalence = 4500/10000 = 45%
300
what kind of screening reduces false positive or true negative errors?
Multiple (or multiphasic) screening
combines single screening tests on selected groups
300
What does a high sensitivity test do?
the higher the sensitivity of the test: the better the test rules out (disproves) a disease within a population.
(true positives)
(SNOUT : Sensitivity high: rules out)
400
What is the Problem with a test being too sensitive?
True positives: disease is present
400
Poultry unit consisting of 10000 layer hens. Initial tests indicated 4500 layer hens had osteoporosis (thin bones). The ration was changed and 3 weeks later 8000 birds were shown to have thin bones .
What is the incidence of osteoporosis?
Incidence = new cases / total population
Incidence = 3500/10000 = 35%
400
What does a high Specificity test do?
the higher the specificity of the test: the better the test rules in (demonstrates) a disease within a population
true negatives
(SPIN : specificity high: rules in)