I would echo to a large degree what Scott said. We talked earlier about lessons learned. One lesson everyone should learn when you're talking about infectious diseases is that you never say “never” and you never say “always”. That's the reality of the species interaction with various pathogens.
Again, I believe that what we're talking about from a biosecurity and animal disease perspective is what we refer to as a low-probability, high-consequence event. As I say, we had the experience in Canada of foot-and-mouth in Saskatchewan. Whether it was infected clothing or boots that introduced the foot-and-mouth virus in material adhering to the clothing or whether, as has also been reported, an infected sausage got dropped into a feed trough and was consumed by pigs, either way, the individual was on the farm for reasonable periods of time working with those animals.
I gave the example of influenza in 2009 and the 22 countries that had it in swine populations, and the five countries that ended up with it in turkey populations—