Analytic epidemiological studies

Analytic epidemiological studies aim to investigate and identify factors associated with the presence of disease within populations. These factors can be classified as one of the components of the 'epidemiological triad' of Host, Agent and Environment

Host factors

These include unchanging characteristics of the host animal such as sex, breed or species, as well as more variable characteristics such as age, nutritional status and stage of pregnancy.

Agent factors

Features of the agent which affect the levels of disease within an infected population include

Environment factors

This category includes a wide variety of factors, encompassing managemental, climatic and ecological features.

Analytic studies

Analytic studies may investigate exposure to these factors in animals with disease, compared to those without, or may compare the occurrence of disease amongst 'exposed' animals to 'unexposed' animals. Although there are considerable difficulties in establishing causation of disease, the results of these studies can provide useful evidence regarding possible risk factors.