Oliver Smithies Lecture: The Ecology of a Pandemic: Interpreting the Ongoing Epizootic of Highly Pathogenic Avian Influenza

The current epizootic of highly pathogenic avian influenza (HPAI) is unprecedented in scale, duration, and ecological reach. While often framed narrowly as a veterinary or virological concern, the spread of this virus among wild birds, domestic poultry, and a growing range of mammalian hosts—including sporadic spillover into humans—raises broader questions about how pandemics emerge and evolve. In this lecture, I explore the ecology of pandemic risk through the lens of the ongoing HPAI epizootic, focusing on how environmental context shapes the transmission, impact, and apparent severity of emerging pathogens. Drawing on recent data, I examine the striking variation in observed case fatality rates and argue that such measures reflect not only viral properties but also the ecological and social systems in which outbreaks unfold. The case of HPAI invites us to reconsider how we define, detect, and prepare for pandemics—and to recognize that risk is rarely evenly distributed or solely biological in origin.