Defining and measuring wildlife health based on twenty years of literature

Wildlife populations face a multitude of challenges including habitat loss and degradation, overexploitation, and disease. Understanding which wild animal populations are healthy, and thus able to withstand these challenges,... [ view full abstract ]

Wildlife populations face a multitude of challenges including habitat loss and degradation, overexploitation, and disease. Understanding which wild animal populations are healthy, and thus able to withstand these challenges, and which are vulnerable is essential for wildlife conservation. The concept of wildlife "health" is meant to incorporate measures of resilience and fitness rather than simply reflecting the presence or absence of disease. However, in the field of wildlife health, there continues to be a focus on studying and monitoring disease rather than considering how to define, monitor, and evaluate health. Our objectives were to examine how wildlife health is defined, valued, and measured in the literature and to compare these findings to parallel areas in other fields such as human health and conservation biology. A literature search of MEDLINE, Biological Sciences, Environmental Sciences and Pollution Management, and Agricola databases was conducted from 1994 to 2014 using the key phrases “wildlife health” and “wild animal health”. This search yielded a total of 833 papers, which were screened by two reviewers and inclusion/exclusion decisions were made by consensus. A total of 456 papers were included and classified by article type (i.e., review, opinion, research, case report), article topic (i.e., pathogen, toxin, other disease, multiple diseases, or non-disease topic), context of health (i.e., health as the absence of disease, health as a multi-factorial concept, or unclear context of health), and unit of measurement of health. Results show that there is no single, shared definition of health for wildlife, the vast majority (82%) of papers focus on disease, and wildlife health is measured in highly variable, and sometimes contradictory, ways. The wildlife health field, which includes a diverse group of professionals, would benefit from further discussions and development of a shared and clear definition of wildlife health.