Veterinary epidemiology studies health status and diseases in animal populations in order to identify determinants underlying the spread both to other animals and, in some cases, to humans. Surveillance is one of the most important tool to assess the epidemiological situation of a disease, it consists of the systematic and continuous collection of information that contributes to detect and measure the presence of a disease in a given area.
An introduction to veterinary epidemiological surveillance in this video produced by the Istitituto Zooprofilattico Sperimentale delle Venezie (IZSVe), an Italian health authority and research organization in the fields of animal health, food safety and zoonoses.