Table 1 Definitions of disease monitoring and surveillance found in three textbooks on veterinary epidemiology.

[1] (page 259)

Animal disease monitoring describes the ongoing efforts directed at assessing the health and disease status of a given population.

The term "disease surveillance" is used to describe a more active system and implies that some form of directed action will be taken if the data indicate a disease level above a certain threshold.

[4] (page 22)

Monitoring is the making of routine observations on health, productivity and environmental factors and the recording and transmission of these observations.

Surveillance is a more intensive form of data recording than monitoring.

(page 358 and 360)

The routine collection of information on disease, productivity, and other characteristics possibly related to them in a population.

An intensive form of monitoring (q.v.), designed so that action can be taken to improve the health status of a population, and therefore frequently used in disease control campaigns.

[2] (page 379)

Monitoring refers to a continuous, dynamic process of collecting data about health and disease and their determinants in a given animal population over a defined time period (descriptive epidemiology).

Surveillance refers to a specific extension of monitoring where obtained information is utilised and measures are taken if certain threshold values related to disease status have been passed. It, therefore, is part of disease control programmes.