Why are population distributions important?
- Because you can see a general trend on what is happening
- population structure and social organization can affect parasite transmission and prevalence
What kind of trends are occurring in our profession?
- More people are going urban over the past 50 years and the people who are rural still don’t have a lot to do with farming
- there are a lot of older ranchers but no one is replacing them when they retire
- there are less cattle ranches but they are bigger– this means it takes less vets to service the ranches
What are three levels of social systems within animal populations?
- at an individual lever
- at a herd level or group level
- within a group
Describe some factors of a social system at an individual level
depends on:
age, sex, reproductive rate, relatedness, position in the dominance hierarchy, social interactions, and patterns of space use
Describe some factors of a social system at a group level
- group sizes vary between and within species
- some species are solitary unless they are breeding
- monogamous pairs
- socially complex groups
- urban environment may affect group size and population distributions
Describe some factors of a social system within a group
- age and social status of an individual
- season
Why do we care about the social systems?
- these will effect number and types of contacts a pathogen will experience
- it will affect the exposure and transmission rates
What does transmission of a parasite among groups depend on?
- group size
- composition
- territoriality
- levels of inter-group movement and contact
What does transmission of a parasite within a group depend on?
- gender
- age
- dominance
- superspreaders
Describe gender transmission within groups
- diseases show a bias towards certain genders (Ex/ TB has higher prevalence among males because they are larger, differences in home ranges and have different sexual behaviour)
- mating behaviour can have implications for disease exposure
- Polygamy is common
- variation in mating success (more successful = more exposure to more females)
Describe age distribution within groups with regards to transmission
- relationship between age and disease prevalence
- if pathogen doesn’t kill the host then prevalence increases with age
- if antibodies tigers persist, seroprevalence is likely to increase with age
- if host can recover from infection and become immune then juveniles may have a higher prevalence then adults
- many adults have already been exposed and recovered
- infants may initially be protected by passive maternal immunity but become susceptible when passive immunity wanes
Descrive social dominance within groups with regards to transmission
- can affect exposure rates and stress levels
- chronic stress can impair immune system
- different breeding behaviour, rank stability and coping mechanisms
Describe super spreaders within a group with regards to transmission
- not all hosts are equally susceptible and infectious– a few individuals often infect a large amount of other
- if focus on these individuals, one may have more luck in controlling the disease
- can become one if social because has more contact with individuals
What are three intergroup factors that effect transmission
- territoriality
- group size and population density
- economic organization of agriculture industry
Describe how territoriality can affect transmission
- aggressive encounters, including biting and scratching, increase exposure to disease
- defensive behaviours cost energy and may increase strew
- may also reduce transmission by reducing contact between individuals and groups because may want to stay in own group
Describe how group size and population density can affect transmission
- affects contact rate
- disease maintenance and transmission enhanced at higher density
- industry economics and structure
- urban habitats
- size of home ranges
- movements and distances travelled
- barriers to dispersal
- habitat requirements
Describe how economic organization of industry can affect transmission
it effects the contact rates and disease transmission because of:
- herd sizes
- herd densities and inter herd contact
- animal movement
- interspecies mixing and within species mixing
- cross boarder movement
How does probabilities and distributions relate to vet med?
we consider the probability of an animal to have a certain problem according to their environment and we classify them into a certain category according to their symptoms so that we can treat them like we have treated other animals in their class
What are three elements of disease?
- the disease or targeted disorder (that we read about in text books)
- the illness (the symptoms)
- the predicament (environment, client limitations)
Describe Clinical Strategy #1: Pattern recognition
instantly realize that what your patient has is what you have treated before
usually visual but can be auditory or by an door
-quick conclusion made
-used increasingly with experience
-cant teach it
-results in several possible diagnoses rather than a single certain one
Describe Clinical Strategy #2: Arborization strategy
Make a flow chart of a large number of potential pathways of diagnosis inquiries
- used when diagnosis is delegated to others
- used more when you have less experience
- used best for conditions with discrete and accretes data or uncommon conditions
- promotes a careful methodical workup but can be inefficient
Describe Clinical Strategy #3: Exhaustive method
Do a complete history and physical and involves searching for all medical facts about the patient.
useful in complex cases but it is very inefficient and rarely used because of this
Also, requires a ton of tests, which don’t tend to improve mortality
Describe Clinical Strategy #4: Hypothetico-deductive strategy
formulation of a short list of potential diagnoses or actions based on early clues and then narrow down the list using other diagnostic strategies like a history and physical exam or lab tests
It is a quick method but instead of finding out what would support their findings, we should be finding things that would rule out the hypothesis (better to rule out things then rule things in)
