Environmental and farm management factors associated with tuberculosis on cattle farms in northeastern Michigan

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

“…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.…”

Tuberculosis

“…Consumption of infected feeds has also been implicated in interspecies disease transmission in which direct contact between species was not evident (eg, the transmission of M bovis between white-tailed deer and cattle in Michigan). 69 Other routes of infection for M bovis have been identified. Transmission through biting has been identified in black-footed ferrets in New Zealand 63,70 and in domestic cats.…”

“…Basic herd hygiene and biosecurity practices (eg, routine testing for tuberculosis and quarantine of imported animals, manure management, and maintenance of feed and water hygiene) have been found to reduce the risks of spread of M bovis on cattle farms. 69,[88][89][90] It has been necessary to establish population control measures for wild reservoir animals (ie, possums, badgers, and white-tailed deer) that may shed tubercle bacilli and contaminate feed and water. Although the main reservoir of M bovis is cattle, there are several instances in which wildlife reservoirs (including European badgers, 91,92 brushtail possums, 93 deer, 42,94,95 African Cape buffalo, 25,44,96 and wild boar 97 ) have been important sources of infection for cattle.…”

“…Reservoir animals infected with tubercle bacilli that interact with cattle may be the source of herd infections and significant production losses. 25,69 The BCG (Bacillus of Calmette and Guerin) vaccine has been used in humans in some countries in which tuberculosis is prevalent in the population. Unfortunately, the BCG vaccine does not completely prevent infection in cattle or other animals 28,98 ; moreover, vaccinated animals yield positive results on the tuberculin skin test, which precludes the use of the vaccine in the United States or other countries with eradication programs.…”

Explanation and Elaboration Document for the STROBE‐Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology—Veterinary Extension

“…Two to 4 control farms matched to each case farm on the basis of type of farm (dairy or beef) and location (inside or outside the TB core area) were included in the study.33 …”