You can give your cat the flu. You can also pass pneumonia to a chimpanzee or tuberculosis to a bird. This kind of human-to-animal disease transmission, known as reverse zoonosis, has been seen on every continent except one: Antarctica. Now, human-linked pathogens in bird poop reveal, for the first time, that even animals on this isolated, ice-bound landmass can pick up a bug from tourists or visiting scientists. This newly identified infection route could have devastating consequences for Antarctic bird colonies, including population collapse and even extinction. “[We’re] obsessed about the potential for novel diseases to jump from wildlife to...