We had a program from 1923, where we were doing active surveillance, right up to 1980 or 1985. Active surveillance means that if you find a case, you go out on most of the farms—based on our statistics—and take samples. If you find cases, then you quarantine and kill animals and continue eradication. We found out that if we kept doing the active surveillance, it wasn't going down more than that. We went into a passive surveillance, which means that we don't go to the farms. When the animals go to the slaughterhouse, we have a program at post-mortem to look at each animal to detect if there's any signs of TB, which seems to be working.
According to research, finding one or two cases every two to three years is very normal. Like I said, each province is considered to be TB free, even if we find a case every two or three years.