ycobacterium bovis belongs to the Mycobacterium tuberculo-sis complex of bacteria and is the main aetiologic agent of bovine
tuberculosis (BTB) as well as being responsible for a proportion of
cases of human tuberculosis (TB). Despite the application of the
test and slaughter policy, the incidence of BTB in GB has increased
steadily since the 1980s and this is thought to be due to the
existence of a wildlife reservoir [1]. Hence, vaccination is being
considered as an additional tool to contribute to the control of BTB
[2]. The live attenuated strain M. bovis bacillus Calmette-Guerin
(BCG) was derived from a case of bovine tuberculoid mastitis in the
early 1900s and has been used as a vaccine against TB in humans
since 1921 [3]. BCG has been used experimentally for vaccination
of cattle against BTB since 1912, including in the UK in the first
half of the 20th century [4,5]. As in humans, BCG confers partial
protection against BTB in cattle [6] and therefore, there is a nee