Animals as Sentinels of Human Environmental Health Hazards: An Evidence-Based Analysis

Despite recognition that animals could be serving as sentinels for environmental risks to human health, there are no evidence-based guidelines for the use of animal sentinel data in human health decision making. We performed a systematic review of the animal sentinel literature to assess the evidence linking such events to human health. A search of MEDLINE identified peer-reviewed original studies of animals as sentinels for either chemical or biological environmental hazards. A limited search of the CAB and AGRICOLA databases was also performed. We classified a random sample of 100 studies from the MEDLINE search according to species, hazard, and health outcome examined; study methods; and linkages to human health. Animal sentinel studies were difficult to locate in MEDLINE because of a lack of adequate key words for this concept. We found significant limitations in the study methods used to investigate animal sentinel events. Clear linkages to human health were frequently absent. Studies of sentinel events in animal populations hold potential for the recognition and control of human environmental health hazards, yet a number of barriers exist to using such data for evidence-based human health decisions. There is a need for greater data sharing and cooperative research between human and animal health professionals regarding environmental hazards and health outcomes in animal and human populations.