Editorial: Developments in animal health surveillance, volume II.

The functions of animal health surveillance include substantiating the absence or distribution of specified disease while facilitating the early detection of exotic or emerging diseases. Ideally, surveillance should be timely, sensitive, easy to implement, inexpensive and resource efficient. Fulfilling these functions and attributes is challenging. Specific challenges include limited resources, the ever-lurking threat of disease incursion or spread, underreporting of cases, sustaining motivation for stakeholder participation and the quest to enhance existing surveillance systems. Overcoming these challenges requires continuous effort and novel approaches.