One Health in two countries: The politics of transdisciplinary healthcare collaboration in Canada and the United States.

The One Health perspective highlights the potential synergies between the human, animal, and environmental health sciences, especially in an era of budget shortfalls, climate change, and emerging infectious diseases of zoonotic origin. Canadian physicians and veterinarians arguably lay the foundation of One Health in the late 19^th century, when they pioneered the study of "comparative medicine" in Montreal, but they fell into disciplinary silos before World War I to the lasting detriment of the Canadian population. This article explores both the advantages and impediments to cross-disciplinary healthcare collaboration in Canada, highlighting the country's vast size, sparse population, and political decentralization in particular, and offers a number of policy recommendations that would allow the country to reclaim its rightful role as a leader in the One Health movement.