In these previous studies, contamination by rapidly growing soil inhabitants may have hampered the further recovery of viable M. bovis cells from infected soil samples (Young et al., 2005). Refined immune-trapping of M. bovis was crucial to avoiding contamination and helped to grow M. bovis mycobacteria within 4 weeks from the soil of 7/7 badger setts (Sweeney et al., 2007). It was recently shown that M. bovis survived as long as 88 days in soil under natural weather conditions (Fine et al., 2011).