West Nile Virus Revisited: Consequences for North American Ecology

It has been nine years since West Nile virus (WNV) emerged in New York, and its initial impacts on avian hosts and humans are evident across North America. The direct effects of WNV on avian hosts include documented population declines, but other, indirect ecological consequences of these changed bird communities, such its changes in seed dispersal, insect abundances, and scavenging services, are probable and demand attention. Furthermore, climate (seasonal precipitation and temperature) and land use are likely to influence the intensity and frequency of disease outbreaks, and research is needed to improve mechanistic understanding of these interacting forces. This article reviews the growing body of research describing the ecology of WNV and highlights critical knowledge gaps that must be addressed if we hope to manage disease risk, implement conservation strategies, and make forecasts in the presence of both climate change and WNV-or the next emergent pathogen.