Plague Exposure in Mammalian Wildlife Across the Western United States.

Plague is caused by a bacterial pathogen () that can infect a wide range of mammal species, but its presence in wildlife is often underappreciated. Using a large-scale data set ( = 44,857) that details the extent of exposure in wildlife, we document exposure in 18 wildlife species, including coyotes (), bobcats (), and black bears (). Evidence of plague activity is widespread, with seropositive animals detected in every western state in the contiguous United States. Pathogen monitoring systems in wildlife that are both large scale and long-term are rare, yet they open the door for analyses on potential shifts in distribution that have occurred over time because of climate or land use changes. The data generated by these long-term monitoring programs, combined with recent advances in our understanding of pathogen ecology, offer a clearer picture of zoonotic pathogens and the risks they pose.