One Health: The Role of Pathology as it Pertains to Diagnosis of Zoonoses and Discovery of Emerging Infections.

Pathologists are an integral part of One Health as they are a critical component of the multidisciplinary team that diagnoses zoonotic diseases and discovers emerging pathogens. Both human and veterinary pathologists are uniquely positioned to identify clusters or trends in patient populations that can be caused by an infectious agent and preface emerging outbreaks. The repository of tissue samples available to pathologists is an invaluable resource that can be used to investigate a variety of pathogens. One Health is an encompassing approach that focuses on optimizing the health of humans, animals (domesticated and sylvatic), and the ecosystem, including plants, water, and vectors. In this integrated and balanced approach, multiple disciplines and sectors from local and global communities work together to promote overall well-being of the 3 components and address threats such as emerging infectious diseases and zoonoses. Zoonoses are defined as infectious diseases that are spread between animals and humans through different mechanisms, including direct contact, food, water, vectors, or fomites. This review highlights examples in which human and veterinary pathologists were an integral part of the multisectoral team that identified uncommon etiologic agents or pathologies that had not been elucidated clinically. As the team discovers an emerging infectious disease, pathologists develop and validate tests for epidemiologic and clinical use and provide surveillance data on these diseases. They define the pathogenesis and pathology that these new diseases cause. This review also presents examples that demonstrate the crucial role pathologists play in diagnosing zoonoses that have an impact on the food supply and the economy.