Bovine TB: the disease, its epidemiology & history of its control in England

1. Bovine TB, caused by the bacterium Mycobacterium bovis (M. bovis), is a chronic, primarily respiratory, disease that can take a variable amount of time (from a few weeks to a lifetime) to develop from infection to clinical disease and to become infectious to other animals. The transmission rate between animals is low and the epidemic only progresses slowly: on average any infected animal is thought to transmit infection to just over one other animal. Animals infected with TB tend to shed M. bovis intermittently in relatively low numbers of organisms (compared to acutely infectious and contagious viral diseases such as Foot and Mouth Disease).