 the more likely they are to acquire mutations that could make it more easy for them to grow in humans, transmit in humans. So the fact that it's in cattle, that it's spreading, that it's continuing to go on there, and that there's a lot of interaction between humans and cattle, that makes it a serious problem. What is it that you've done in this latest set of experiments to try and, I suppose, narrow down the kind of threat it might be to people?