Moving-Average Trigger for Early Detection of Rapidly Increasing Mortality in Caged Table-Egg Layers

作者：Malladi Sasidhar^*; Weaver J Todd; Clouse Timothy L; Bjork Kathe E; Trampel Darrell W

来源：Avian Diseases, 2011, 55(4): 603-610.

DOI：10.1637/9636-122910-Reg.1

• detection trigger
• early-warning system
• surveillance
• highly pathogenic avian influenza
• egg-layers

Rapidly increasing and unexplained mortality in commercial poultry flocks may signal the presence of a highly transmissible and reportable disease. Activation of an infectious-disease surveillance system occurs when a key production parameter, i.e., mortality, changes. Various triggers have been proposed to alert producers when mortality exceeds normal limits for a given production system to enable early detection of such diseases. In this article we demonstrate that a simple moving-average trigger is useful for detecting any disease syndrome in caged table-egg layer flocks that manifests itself as sudden, rapidly increasing mortality. We superimposed HPAI disease mortality output data derived from a disease transmission model and from a naturally occurring HPAI outbreak onto normal mortality data from 12 healthy commercial egg-layer flocks, and compared the performance of 7-day moving-average triggers to previously proposed triggers. The moving-average trigger is more efficient, resulting in fewer false-positive alerts and an earlier time to disease detection. It can be easily calculated by using a computer spreadsheet providing only 7 days of mortality data and can be practically and inexpensively implemented by large commercial poultry integrators. A moving-average trigger can be an active component of a production-based surveillance system.

• 出版日期2011-12