A very good vet, in the area with the highest incidence of Bovine TB, told me the real problem with TB and badgers is cross-contamination. Badger and Deer populations re-infect each other. Sick deer can't travel far to forage, they head for pasture for nice lush grass, if there close to deer. Infected deer cough when foraging leaving phlegm on pasture......
they build water troughs big enough so badgers can't climb into them......