Sick:infection and behaviour

Question 1

How can behaviour shape infection?

Answer 1

behaviour can shape infection by altering the likelihood of hosts getting infected or transmitting a pathogen onward

Question 2

What are three behaviours associated with infection risk?

Answer 2

• behaviours associated with infection risk
  
  • boldness; bold deer mice are not only in contact with conspecifics more frequently but they are also three times as likely to be infected by hantavirus
  • social connectivity: in chimpanzees models demonstrate that a greater proportion of the population becomes infected when epidemics originate in individuals with large numbers of direct contacts
  • avoidance behaviour: caterpillars will actively avoid areas where the infection has been contacted by other caterpillars

Question 3

What are the collective behaviours in spiders which might lead to an outbreak?

Answer 3

collective behaviours in spiders - trade off between attacking the pray with many individuals and sharing the bacteria between them which might lead to an outbreak

Question 4

What is behavioural fever?

Answer 4

they developed a fungi to fight of the swarms of insects that were threatening food security of Africa
behavioural fever - the infected groups would find the hottest place they could stand and not kill themselves which then resulted in the death of the pathogen ( you basically cook it off)

Question 5

Give an example of altering collective behaviour after infection?

Answer 5

when you inject a vampire bat with an infection causing agent they deliver less grooming to other members of the colony
the infected bats dropped the number of connections to other members of the colony; they are basically self quaranting themselves

Question 6

What is illness induced anorexia?

Answer 6

• sick animals will reduce the amount of food they eat
• crickets eat less food when they are challenged with bacteria
• they do this whether the challenge is live or dead
• they changed what they were willing to eat - increased mortality when on high fat diet
• head is very low fat - yum yum, cricket like
• there is a particular enzyme important for digesting lipids and it is also important for mounting an immune response and when the cricket tries doing both of these at the same time it fails → avoiding high fats = better immune response

Question 7

What is parasitic manipulation?

Answer 7

• the ability of certain parasites to modify host behaviour, appearance or physiology to their own advantage
• zombie ants - proteins secreted by the fungus can cause a change in behaviour
• krickets jumping in water

Question 8

Give an example of manipulation in vectors

Answer 8

when you infect a flea with a certain variant of the plague a biofilm is produced that causes certain blockage - the flea unable to process blood so it is constantly hungry → goes to bite more hosts - affects the transmission of the disease
infection alters the mortality of the flea - trade off between how many times the flea bites and how quickly it dies as the effect of infection

infection alters the mortality of the flea - trade off between how many times the flea bites and how quickly it dies as the effect of infection

Question 9

How does the malaria parasite manipulate the mosquito’s behaviour?

Answer 9

when the parasite is developing in the mitgut the mosquitos are not that interested in interacting with a host but when they become infectious that changes dramatically
infected mosquitos in the pre-infectious period are not able to smell the hosts as well and because of this senescence when they can smell them n the infectious period they overshoot the sensitivity and therefore better detect hosts
surprisingly it doesn’t matter if the mosquito was succesfully infected to exhibit the change in behaviour, it only matters that they fed on an infected mouse

Question 10

Why does immune challenge alter to drive host-seeking responses

Answer 10

changes how the mosquito distributes the resources and that alters the host seeking behaviour

Question 11

Can we exploit differences in behaviour and physiology to improve control?

Answer 11

• we could potentially alter the host seeking behaviour of mosquitos to bite people less
• however a lot of barriers we have now (like bednets) rely on the host seeking behaviour so if we alter how that slice of the population interacts with our barriers it might be potentially problematic

Question 11

What were the results of the budget culling studies?

Answer 11

• Data indicate that culling influenced both the activity and spatial organization of badgers.
  In culling areas: Badger abundance was markedly reduced (suggesting lower probabilities of contact) but ranging behaviour increased (suggesting higher probabilities of contact).
• Not surprisingly, badger abundance appears to have been reduced to a lesser extent in reactive culling areas, but ranging behaviour was also somewhat elevated.
• Data suggests that culling could INCREASE transmission by increasing contact between badgers (home ranges) and between badgers and cattle (distance moved)

During and after cull there is a 61% increase in monthly home range
A 39% increase in the distance they move from their home sett
A 45% Increase in the number of fields visited
A 19.9-fold increase in odds of trespassing

…Culling increases badger movement and interactions between badgers and cattle