Dr. John Griffin:

There is still some debate about that. If a cow goes sniffing at a badger sett, it rumbles the ground and thereby creates an aerosol. This might be the mechanism. The infection in the animal is still in the respiratory system, so the organism ultimately gets into the lungs, but there is little doubt now, thanks to strong evidence, that indirect transmission is important. It is especially important in terms of badger setts, which are very contaminated environments, with badgers going in and out constantly, their latrines and so forth. This is a real risk. One bit of advice I would give farmers is to fence off their badger setts. They do not have to prevent the badgers from getting into the fields. They just have to fence off the setts so that their cattle do not have access to them indirectly. I hope I have answered the Senator’s question.