Translations:Advanced Field Epi:Manual 1 - Disease Investigation/313/en

Where the investigation involves a relatively small area (one farm or one village) it may be possible to assess all (or nearly all) animals at that location and assign them to either cases or non-cases. These two groups may then form the basis of a study. If you are able to collect data on all animals at the location and if you can confidently determine onset of disease then this will form a cohort study and not a case-control study and you will be able to estimate incidence or prevalence measures and use relative risk as the statistical measure of association between disease and risk factors.