What is the Role of Veterinary Epidemiology?
by reading this topic in the workbook (or online)
The third major function of epidemiology is to apply
our results, and then to evaluate the effectiveness of interventions
and strategies for improvement of animal health and welfare.
With observational epidemiology, we can assess the impact
of animal health services on the health and productivity of an animal
With interventional epidemiology, we can assess the effect
of a specific animal health intervention.
We can use individually-randomised controlled trials (where
each participating animal is randomised separately, as an individual)
to compare a new treatment with an established one.
Sometimes it may be better to randomise at the level of the herd
rather than the individual animal.
For example, when assessing the impact of wildlife vaccination
on tuberculosis in cattle one would randomise herds rather than
So in this case, a number of suitable herds would be selected,
and then each herd (with all its inhabitants) was randomised to
have the local wildlife population vaccinated or not.
We will discuss these in Chapter 17 --Intervention studies.
The challenge of epidemiology is that we must make these comparisons
not in a highly-controlled environment such as a laboratory, but
in a real-life situation where there is a lot of "background
noise". We work with real populations and have to compare exposures
and outcomes in situations where there may be many sources of confusion
and error. This is a particular problem of observational studies.
An important part of the process of learning about epidemiology
is to understand how such mistakes may arise and to know how to
minimise them. We will return to these issues later in the course.