Scientists worry that the losses may open the door to human, plant and animal diseases that would otherwise have been caught.
Author: Apoorva Mandavilli and Emily Anthes
Bird Flu Is Infecting More Mammals. What Does That Mean for Us?
H5N1, an avian flu virus, has killed tens of thousands of marine mammals, and infiltrated American livestock for the first time. Scientists are working quickly to assess how it is evolving and how much of a risk it poses to humans.