Overview
This lecture covers the definition and study of wildlife diseases, the evolution of disease
causation concepts, methods for establishing cause and effect, and key epidemiological
terminology and measurements.
Definition of Disease and Relevance
● Disease is anything that reduces the fitness (health or survival) of an organism.
● Disease management is often for human benefit (food sources, economic value,
public health).
● Wildlife diseases can impact food sources, public health, and have economic
consequences.
Historical Concepts of Disease Causation
● Early theories included "bad air" (miasma) and contagion-venom (living agents in
the air).
● The understanding of specific disease agents began in the 1800s.
● Disease causation is usually multi-factorial, not just one agent causing one
disease.
Methods of Identifying Causation
● Koch’s Postulates: One cause, one effect; agent must be present in every case,
isolated, and reproduce disease in a new host.
● Most wildlife diseases don’t fit this—multiple factors (environment, host, agent)
are often involved.
● The agent-host-environment triangle considers all contributing elements for
disease occurrence.
This lecture covers the definition and study of wildlife diseases, the evolution of disease
causation concepts, methods for establishing cause and effect, and key epidemiological
terminology and measurements.
Definition of Disease and Relevance
● Disease is anything that reduces the fitness (health or survival) of an organism.
● Disease management is often for human benefit (food sources, economic value,
public health).
● Wildlife diseases can impact food sources, public health, and have economic
consequences.
Historical Concepts of Disease Causation
● Early theories included "bad air" (miasma) and contagion-venom (living agents in
the air).
● The understanding of specific disease agents began in the 1800s.
● Disease causation is usually multi-factorial, not just one agent causing one
disease.
Methods of Identifying Causation
● Koch’s Postulates: One cause, one effect; agent must be present in every case,
isolated, and reproduce disease in a new host.
● Most wildlife diseases don’t fit this—multiple factors (environment, host, agent)
are often involved.
● The agent-host-environment triangle considers all contributing elements for
disease occurrence.
