Special Topics

Question 1

rabies

Answer 1

• Caused by viral infection (lyssaviruses)
• Spread through bites, scratches, etc. From infected animal
• Early symptoms: fever, exposure site irritation
• Later symptoms: uncontrolled movements, confusion, paralyses, loss of consciousness, hydrophobia, aggression, etc.
• Almost always fatal
• Most common source: dogs and bats
• Vaccine introduced in 1885

Question 2

what causes rabies symptoms?

Answer 2

• Viral infection causes inflammation of the brain and meningeal coverings
• Neuroinflammation impacts behaviour

Question 3

how does neuroinflammation affect behaviour (rabies)?

Answer 3

• Can result in agitation, paralysis, paranoia/terror, hallucinations, delirium
• Hydrophobia:
• • Patient has difficulty swallowing
• • Panic when presented with liquids – spasms of throat muscles
• • Uncontrollable thirst

Question 4

why is hydrophobia a symptom of rabies?

Answer 4

Virus multiplies in the salivary glands (minimal liquid intake – increase viral load for ease of transmission)

Question 5

parasitic fungus and ants

Answer 5

• Parasite releases chemicals that impact brain function and behaviour
• Causes ants to leave their nests and attach mandibles to vegetation, allowing the virus to spread via spores that come from infected ant

Question 6

platypus

Answer 6

• Duck-billed platypus = monotreme (only mammals to lay eggs)
• First described as “amphibious mole-like creature”
• Live in Eastern Australia
• Uses electrolocation
• Males are venomous: spur on hind leg containing defensin-like proteins (DLP’s)

Question 7

platypus electrolocation

Answer 7

• ability to locate prey through detection of electric fields due to electroreceptors located within the bill
• evolved to improve hunting abilities in murky waters

Question 8

venomous male platypuses

Answer 8

• DLPs produced by immune system, cause bacterial lysis, used in defense to kill small animals
• Venom production increases during the breeding season – role in aggression
• Female spur buds don’t completely develop – no venom production

Question 9

autism in the animal kingdom

Answer 9

• Hallmark features of autism in humans: asocial behaviours, decreased understanding of social cues, impaired verbal abilities, repetitive behaviours, restricted interests
• Problem: Many of these hallmark behaviours are difficult to identify in wild animals, most of these behaviours also wouldn’t be selected for in the wild
• Autistic-like behaviours are being modelled in labs, but this is difficult to do because we don’t know what causes it
• Ultimately, unsure if it exists in animals