Husbandry practices, badger sett density and habitat composition as risk factors for transient and persistent bovine tuberculosis on UK cattle farms

Farm characteristics and farmer perceptions associated with bovine tuberculosis incidents in areas of emerging endemic spread

“…In contrast to previous studies (Johnston, Gettinby et al 2005, Reilly and Courtenay 2007), maintenance of a closed herd i.e. a herd into which no movements were recorded in the two years prior to the case incident, was not a significantly protective risk factor in any model, after controlling for herd size, compared to farms that had purchased animals.…”

“…While herd-level risk factors have been relatively well studied for herds in the high incidence areas of England and Wales (Johnston, Gettinby et al 2005, Reilly and Courtenay 2007, CarriqueMas, Medley et al 2008, Ramírez-Villaescusa, Medley et al 2010, Karolemeas, McKinley et al 2011, Mill, Rushton et al 2012, Northern Ireland (Denny and Wilesmith 1999), Ireland (Griffin, Hahesy et al 1993, Griffin, Martin et al 1996, Europe (Marangon, Martini et al 1998, Garro, Abdala et al 2010, Humblet, Gilbert et al 2010) and further afield (Kaneene, Bruning-Fann et al 2002, Porphyre, Stevenson et al 2008, Javed, Irfan et al 2011, the factors that predispose or protect a herd against bTB are less well defined in areas of emerging endemicity. There are often inconsistencies in the risk factors that different studies identify, and most are based in long-standing endemic areas.…”

Risk factors for herd breakdown with bovine tuberculosis in 148 cattle herds in the south west of England

“…In both situations, M. bovis organisms are likely to have survived and been put onto 307 the pasture whist alive, suggesting a process by which M. bovis can be transmitted via pasture. This is 308 important because the public health recommendations for storage and spreading of slurry (the most common 309 form of faeces from dairy cattle farms) reduce exposure to sunlight and may enhance pathogen survival 310 (Menzies and Neill, 2000;Scanlon and Quinn, 2000).The storage of manure for 6 months or more was 311 reported as a risk for transient HBD as opposed to persistent HBD with farm restrictions for more than 6 312 months by Reilly and Courtenay (2007). 313…”

Control of bovine tuberculosis in British livestock: there is no ‘silver bullet’

“…However, an assessment of the potential additional risk from deer is reliant on knowledge of the spatial distribution and abundance of the principal wildlife host, the badger, which has generally been the limiting factor in landscape-scale analyses of bTB incidence [24][25][26]47]. Significant associations between bTB persistence and badger-sett density have now been found at the farm scale [48] and recently published, improved models of badger abundance [49] now enable the association between bTB in cattle and badger density to be explored with greater confidence.…”

“…However, an assessment of the potential additional risk from deer is reliant on knowledge of the spatial distribution and abundance of the principal wildlife host, the badger, which has generally been the limiting factor in landscape-scale analyses of bTB incidence [24][25][26]47]. Significant associations between bTB persistence and badger-sett density have now been found at the farm scale [48] and recently published, improved models of badger abundance [49] now enable the association between bTB in cattle and badger density to be explored with greater confidence.Risk maps based on the distribution of known or suspected hosts and vectors can be a valuable tool for disease management [50,51], in particular in relation to the identification of potential high-risk areas where introduced disease might establish in the host community. The increasing British deer population [52] means that the size and diversity of the potential bTB host community is also expanding in certain areas.…”