Why is bird flu highly lethal to some animals, but not to others?
Why has bird flu killed millions of wild and domestic birds, touched seals and sea lions, mink farms, cats, dogs and others but hardly touched people? That's "a little bit of a head-scratcher,” although there are some likely explanations, said Richard Webby, a flu researcher at St. Jude Children’s Research Hospital in the US state of Tennessee. It could have to do with how infection occurs or because species have differences in the microscopic docking points that flu viruses need to take root and multiply in cells, experts say. But what keeps scientists awake at night is whether that situation...