Dr. Damien Barrett:

New Zealand has an eradication programme that really kicked off substantially in the late 1980s and early 1990s and, at the moment, it is down to somewhere between 20 and 25 positive herds. That programme involved a couple of elements that we are also looking at.

The predominant one was the idea of risk-based trading and that herds could only trade with a herd of an equivalent or superior TB status. We also carried out interferon-gamma testing to quite a substantial level. That is the blood testing. They have a wildlife reservoir - possums - but they have a wildlife programme as well.

What makes it difficult for us to eradicate TB, particularly compared to our northern European neighbours, is the presence of wildlife reservoirs and the issues of spillover and spill back. That makes it particularly challenging.