I'll tackle the first one, and look to my colleague if I make any mistakes.
We have worked very hard on this since the 1920s. Among other countries that have similar systems to ours in managing animal health—the U.S., the U.K., New Zealand, Australia—I think Australia and Canada are the two countries that don't have TB in domestic herds.
If we find a case of TB, we look at the economics. It's much better for us to eliminate it and clean it and then start again. The disease is so slow that you never know—it might flare up if you keep the animals there for any length of time.
The U.S. moved away from the program we have, and a number of states are infected. Now they cannot eliminate TB from their domestic herd. That's why we want to continue to do what we are doing. At the most we spend about $40 million every five years to do this. That was the cost the last time we did it in Alberta. It might be less this time, because it's a smaller problem. The U.S. will spend that much money almost every year. From the point of view of economics, it's better.
To your second question, about why we care if it is so low: back when TB was quite prevalent in bovine populations, about 6% or 8% of human cases were from bovine TB. Now we see virtually nothing. If we let it go and TB starts appearing in our cattle population, we might start seeing human cases again. Given that we have to give antibiotics for a year, and given the human health impacts and the impacts on the health and social systems, I think it's better to continue.