Behaviour and Disease Flashcards
What is the detailed description, list or inventory of all the different kinds of behaviour or activity of a species called?
An Ethogram!
What are extensively used by veterinarians to aid in diagnosis?
Changes in behaviour, activity or posture
Why does behaviour have an important role in diagnosing disease?
- Many diseases initially present as behaviour changes or problems
Before diagnosing a primary behaviour problem and initiating behavioural therapy, what must be ruled out?
Medical differentials
Why might disease pathogens be adapted to cause behavioural changes in their host?
To increase chance of transmission
Ex. rabies spread great bc it causes biting behaviour
What type of ‘state’ is sickness?
A motivational state
Motivation states are states that cause animals to behave in a certain way
What other motivational states does sickness compete with?
- hunger, exploration, reproduction, learning
- sickness often overwhelms or co-opts other motivational states
What is the “Acute-Phase Response” to cytokines?
- fever
- inappetance
- increased sleep
- postural changes
- reduced motion, grooming
- isolation from others
What are the short term advantages and long term disadvantages of adaptive cytokine responses?
Short term advantages:
- energy saving
- promotion of body defense mechanisms
Long term disadvantages:
- burning through a lot of energy maintaining the “acute-phase response”
How does the immune system influence behaviour?
Just as the brain uses humoral and neural paths to affect the immune system, the immune system uses humoral and neural paths to affect the brain and influence behaviour
Why might have acute phase responses evolved?
As strategies for addressing extreme threats to survival of a group, population, or species
Why is there a reduced likelihood of clinical signs being expressed in unfamiliar environments? Why do some animals look okay when the vet arrives?
Expression of sickness behaviour is context-dependent which reduces likelihood of clinical signs being expressed in unfamiliar environments.
- behavioural responses may be more readily expressed in familiar environments and amongst familiar conspecifics
How are welfare and disease linked?
- disease will often cause poor welfare
- poor welfare, resulting from a wide variety of different external causes, may make disease more likely, often by initiating immunosuppression
What is the definition of stress?
An environmental effect on an individual that overtaxes its control systems and results in adverse consequences and, eventually, reduced fitness
What are 4 responses to stress?
- brain activity (reduced or focused)
- adrenal and other physiological responses (humoral or neural)
- immunological suppression (down regulation of immunity)
- behavioural changes
What is the stress response?
- stressors affect the BRAIN
- hypothalamus responds and releases CRH
- CRH acts on the anterior pituitary to release ACTH
- ACTH acts on the adrenal cortex to release cortisol
- Cortisol acts as a negative feedback loop to the hypothalamus and anterior pituitary
What are responsible for causing sickness behaviour?
Proteins (i.e. cytokines) secreted by activated macrophages
Cytokines transmit messages from the immune system to the brain via humoral and neural pathways
How can sickness behaviour generally be described? What is its impact?
A well-organized adaptive response of the host animal that may enhance disease resistance and facilitate recover, or avoid transmission within the population
Think back to the case study, what types of questions were asked?
Generating a “History” and “Signalment” (aka signs animal is showing that may signal what systems are involved
What role does behaviour have in diagnosing disease?
Changes in behaviour, activity or posture brought about by disease are extensively used by veterinarians to aid in diagnosis.
- Many diseases initially present as behaviour changes or behaviour problems
- Medical differentials must be ruled out before diagnosing a primary behaviour problem and initiating behavioural therapy
What is ‘sickness behaviour’?
Sickness behaviour is a motivational state. Behavioural priorities are re-organized in sick animals.
Why does behaviour change when an infection or other illness occurs?
Disease pathogens may be adapted to cause (or avoid causing) behavioural changes in their hosts that will increase the chance of transmission.
Sickness is a motivational state that competes with other motivational states such as: hunger, exploration, reproduction, learning.
How does the brain know the rest of the body is sick?
The adaptive cytokine responses. The immune system uses humoral and neural paths to affect the brain and influence behaviour.
The animal is infected by the pathogen. Cytokines secreted by activated macrophages go to the brain to signal information. The brain translates this info and signals new behaviours with the goal that it won’t spread the infectious pathogen aka causes sickness behaviour.
What are behavioural changes due to cytokine response?
Increased sleep, postural changes, reduced motion (grooming), isolation from others
Acute phase responses may have evolved as strategies for addressing extreme threats to survival of a group, population, or species. But for individual animals behavioural and inflammatory acute-phase responses during illness can make the animals “sicker” and impair prognosis, particularly for neonatal animals.
What is evoked behaviour?
An animal’s response to standard stimuli
What are some examples of uses of behaviour for disease diagnosis?
- Daily routines (eating, elimination, grooming)
- illness may influence the pattern of behaviour shown by animals in a 24hr period
- the normal behaviour pattern needs to be established before alterations to the pattern by a parameter like pain can be confirmed - Evoked behaviour
- Response to analgesic treatment
