Population Distributions Flashcards
What is the epidemiological triad?
Host
Agent
Environment
Where the 3 meet = disease
Within a group what will affect the # and types of contacts a pathogen will experience?
Sex
Age
Social status of individual
What does transmission of a parasite among a group depend on?
Group size
Compostion
Territoriality
Levels of inter-group movement and contact
Why would a disease be bias towards a certain gender?
Larger animals more susceptible to vectors
Sex related differences in home ranges
Sex related differences in physiology/behavior
Examples of gender bias diseases
West Nile - odler males
Bovine TB - Males
CWD - Males
Why would males possibly have higher risk of infection to some diseases?
Higher stress levels during breeding season
3 ways age distribution can affect disease spread
- If hosts can recover from infection and become immune, juveniles may have a higher prevalence than adults
- many adults may have already been exposed and recovered
- Infants may initially be protected by maternal immunity and become susceptible when passive immunity wanes
Within group factors
- Gender
- Age
- Dominance
- Superspreaders
What may be most effective disease control strategy?
Problem with this?
- Focus control efforts on superspreaders
2. Difficult to identify
3 Intergroup factors?
- Territoriality
- Group Size/Pop Density
- Economic organization or ag industry
How can economic organization of industry affect transmission?
Herd sizes
Animal movement
Inter-species mixing
Cross border movement of animals
What 2 things is diagnosis all about?
Probabilities
Distribution
Why is clinical diagnosis important?
An effort to recognize the class or group to which a patient’s illness belongs, so that based on prior experience we can guide our process of healing
3 elements of disease
- The disease or target disorder
- The illness
- The predicament
4 Clinical diagnostic strategies?
- Pattern recognition
- Arborization Method
- Exhaustive method
- Hypothetico-deductive strategy
Explain Pattern recognition
Instantaneous realization the patients presentation conforms to a previously learned picture
Reflexive not Reflective
Explain Arborization strategy
Flow chart of a large number of potential preset pathways of diagnostic inquiries
Excelent tool for uncommon conditions
May be poor at handling atypical case presentations
Explain exhaustive method
Painstaking, invariant search for all medical facts about the patient
Method of the novice, abandoned by the experience
Explain hypothetico-deductive strategy
Formulation of a short list of potential diagnoses or actions based on early clues
One flaw with hypothetico-deductive strategy?
Most clinician seek evidence that will support their hypothesis rather than “rule out” their hypotheses
