Preparing for a pandemic

摘要

It is hard to imagine that the aches and pains that most people know as flu could mutate into a superflu that might kill tens of millions of people within two years. And yet, if superflu strikes-as it has done three times in the past century-that is what may well happen. In the global influenza pandemic of 1918, 25m-50m people died. Many scientists now believe that another influenza pandemic is inevitable some time soon. These concerns might be little more than another background worry if it were not for the fact that there is currently a strain of bird flu in widespread circulation to which humans have no natural immunity. This strain has killed more than 60 people so far, about half the number infected. Small pockets of human-to-human transmission have already been seen, and health officials are worried that the widespread geographical extent of bird flu means that it is not a question of if a strain emerges that can be transmitted easily between humans, but when.