Amidst all the swine flu hype and hysteria, the hand-wringing and hand-washing, we have a lot of questions. How bad is this particular flu going to be – more like the usual seasonal viruses, or like the rapacious 1918 version that killed millions worldwide? Will a vaccine be available soon? What are the distinguishing symptoms? But one question seems to be going unasked: how does the flu virus feel about all this?

A virus does not have feelings, exactly. It infects without foresight, malice or mercy. But to understand a disease, it is important to look at things from the point of view of the organism – virus, bacteria or worm – that causes it. Take virulence, for example, the degree of damage a pathogen does to its host. The conventional wisdom used to be that a proper disease evolved to become relatively benign; why bite the hand that feeds you, not to mention the vital organs making that feeding possible?