Unusual morbidity or mortality event (cause undetermined)

The term “unusual morbidity/mortality” is inherently difficult to define, especially as it pertains to wildlife species; for the purposes of this technical card, a morbidity or mortality event in wildlife is defined as a noteworthy occurrence of one or more sick or dead animals clustered in space and time. An event may be considered unusual if the aetiology is unknown or if the circumstances surrounding an identified disease occurrence differ from what is anticipated (e.g., changes in temporality or seasonality, geographic or spatial
distribution and/or demographic composition; atypical clinical signs of disease; change in species affected; or morbidity/mortality beyond what is typically expected or observed).