Bovine tuberculosis elimination: playing the long game.

Bovine TB (bTB) is a global disease (Fig 1) that has been around for centuries, with evidence of disease identified in prehistoric bovine remains.1 It is likely that close contact between cattle, people and other animals has facilitated transmission since the agricultural revolution.2 Mycobacterium bovis was first identified as the cause of bTB in the early 1900s, which led to the elucidation of zoonotic transmission between cattle and people in the British and Irish dairy industries.3 Since then, many industrialised countries have tried to eliminate M bovis from cattle populations to protect public health and trade, but only a few have achieved it. Australia took less than 30 years to coordinate elimination of bTB. An intensive national elimination programme was only successful after tackling herds or areas with persistent and recurrent breakdowns.4 Fig 1: Countries reporting cases of bovine TB (bTB) to the World Organisation for Animal Health (OIE) between July and December 2017.20 Note this map only records cases reported, rather than the official bTB status of each countryMap: World Organisation for Animal Health (OIE)This historical snapshot illustrates the ability of M bovis to persist in cattle populations and why it is vital to understand the drivers for persistence in long-term bTB elimination programmes. In a study summarised on p 622 of this week’s Vet Record , Houtsma and others investigate the trend in bTB recurrence in Irish herds between 1998 and 2015. Like many other countries aiming to eliminate bTB, Ireland’s control strategy focuses on passive abattoir surveillance and active herd testing for the identification and removal of infected cattle.5 Recurrence in herds decreased over the …