Disease: Tuberculosis
This page provides general information about this condition. Text can be revealed by clicking on the green headers. Links to press releases, results from DWHC investigations as well as other useful documents and relevant literature available on the DWHC website can be found at the bottom of the page.
Pathogen
Tuberculosis is an ancient disease that can affect many species of animal, including man. It is typically caused by bacteria belonging to the Mycobacterium tuberculosis complex which, amongst others, includes M. tuberculosis (considered the main pathogen in human cases of tuberculosis), M. bovis (the usual cause of tuberculosis in ruminants, often referred to as bovine TB), and several other sorts. It is important to note that disease caused by these pathogens is not limited to these common hosts but can occur in other species: For example, cases of infection with M. tuberculosis have also been reported in dogs and horses [1,2] and M. bovis in people [3].
The oldest reported case of tuberculosis occurred in the now-extinct ‘long-horned’ bison (Bison cf.antiquus) from which genetic material was isolated from lesions on the legs [4].
The bacteria is typically spread via the air in small droplets of mucus or saliva formed when infected animals cough or sneeze. These infectious droplets are breathed in and tend to establish infection in the lungs. Another recognised route of transmission between infected cattle and man is the consumption of unpasteurized milk [3].
In the majority of European countries tuberculosis in domestic animals / livestock has been controlled thanks to the stringent testing of cattle.
However, in some countries certain wildlife species are infected and act as a reservoir of disease. For example, M. bovis is present in wild boar (Sus scrofa) and red deer (Cervus elaphus) in France and Spain and in badgers (Meles meles) in the UK and Ireland [6,7,8]. M. caprae, another member of the M. tuberculosis complex, occurs in red deer, cattle and people in Austria and South Germany [9,10].
The Netherlands has a TB-free status although individual cases of infected cattle being imported are reported almost every year [11]. In the Netherlands, during the period from December 2012 until April 2014, 104 badgers were tested for the presence of Mycobacterium tuberculosis complex bacteria as part of a joint project between the DWHC and the Central Veterinary institute in Lelystad; all samples were negative (for more details see the published study results: https://www.dwhc.nl/en/geen-tbc-dassen-nederland/).
References:
- Accidental infection of veterinary personnel with Mycobacterium tuberculosis at necropsy: a case study. Posthaus H, Bodmer T, Alves L, Oevermann A, Schiller I, Rhodes SG, Zimmerli S. Vet Microbiol. 2011 May 5;149(3-4):374-80.
- Pulmonary disease due to Mycobacterium tuberculosis in a horse: Zoonotic concerns and limitations of antemortem testing. Lyashchenko KP, Greenwald R, Esfandiari J, Lecu A, Waters WR, Posthaus H, Bodmer T, Janssens JP, Aloisio F, Graubner C, Grosclaude E, Piersigilli A, Schiller I. Vet Med Int. 2012;2012:642145.
- Human Mycobacterium bovis infection in the United Kingdom: Incidence, risks, control measures and review of the zoonotic aspects of bovine tuberculosis. de la Rua-Domenech R.,. Tuberculosis (Edinb). 2006 Mar;86(2):77-109
- Mycobacterium tuberculosis complex DNA from an extinct bison dated 17,000 years before the present. Rothschild BM, Martin LD, Lev G, Bercovier H, Bar-Gal GK, Greenblatt C, Donoghue H, Spigelman M, Brittain D. Clin Infect Dis. 2001 Aug 1;33(3):305-11.
- A review of infection of wildlife hosts with Mycobacterium bovis and the diagnostic difficulties of the ‘no visible lesion’ presentation. Gavier-Widén D, Cooke MM, Gallagher J, Chambers MA, Gortázar C. N Z Vet J. 2009 Jun;57(3):122-31.
- Mycobacterium bovis in wildlife in France. Zanella G, Durand B, Hars J, Moutou F, Garin-Bastuji B, Duvauchelle A, Fermé M, Karoui C, Boschiroli ML. Zoonoses Public Health. 2012 Sep;59 Suppl 2:170-8.
- Progress in the control of bovine tuberculosis in Spanish wildlife. Gortazar C, Vicente J, Boadella M, Ballesteros C, Galindo RC, Garrido J, Aranaz A, de la Fuente J. Vet Microbiol. 2011 Jul 5;151(1-2):170-8.
- Bovine tuberculosis infection in wild mammals in the South-West region of England: a survey of prevalence and a semi-quantitative assessment of the relative risks to cattle. Delahay RJ, Smith GC, Barlow AM, Walker N, Harris A, Clifton-Hadley RS, Cheeseman CL.Vet J. 2007 Mar;173(2):287-301.
- Infection of red deer, cattle, and humans with Mycobacterium bovis subsp. caprae in western Austria. Prodinger WM, Eigentler A, Allerberger F, Schönbauer M, Glawischnig W. J Clin Microbiol. 2002 Jun;40(6):2270-2.
- Tuberculosis in cattle – surprisingly re-emerging or continuously present?. Moser I, Köhler H, Menge C. Tierarztl Prax Ausg G Grosstiere Nutztiere. 2014;42(4):240-9; German
- Spierenburg, M.A.H, Valkenburg, S.M. & Zijderveld, F.G. van (2014). Import van met TBC besmette runderen uit officieel vrije lidstaten. Tijdschrift voor Diergeneeskunde 12: 28-31
Signs in animals
In chronic infections characteristic lesions may develop. These may take the form of lumps or swellings filled with a creamy-white chalky material. Infected animals are normally severely underweight, although this is not unique to tuberculosis and as small and early-stage lesions may easily be missed TB cannot be ruled out based on macroscopic investigation alone [5].
In order to confirm infection diagnostic testing is essential and may include microscopy and/or molecular techniques and bacterial culture to identify the bacteria.5. A review of infection of wildlife hosts with Mycobacterium bovis and the diagnostic difficulties of the ‘no visible lesion’ presentation. Gavier-Widén D, Cooke MM, Gallagher J, Chambers MA, Gortázar C. N Z Vet J. 2009 Jun;57(3):122-31.
Infection of animals
The bacteria is typically spread via the air in small droplets of mucus or saliva formed when infected animals cough or sneeze. These infectious droplets are breathed in and tend to establish infection in the lungs. Another recognised route of transmission between infected cattle and man is the consumption of unpasteurized milk [3].
Infection of people
The bacteria is typically spread via the air in small droplets of mucus or saliva formed when infected animals cough or sneeze. These infectious droplets are breathed in and tend to establish infection in the lungs. Another recognised route of transmission between infected cattle and man is the consumption of unpasteurized milk [3].
Geographical distribution
In the majority of European countries tuberculosis in domestic animals / livestock has been controlled thanks to the stringent testing of cattle.
However, in some countries certain wildlife species are infected and act as a reservoir of disease. For example, M. bovis is present in wild boar (Sus scrofa) and red deer (Cervus elaphus) in France and Spain and in badgers (Meles meles) in the UK and Ireland [6,7,8]. M. caprae, another member of the M. tuberculosis complex, occurs in red deer, cattle and people in Austria and South Germany [9,10].
The Netherlands has a TB-free status although individual cases of infected cattle being imported are reported almost every year [11]. In the Netherlands, during the period from December 2012 until April 2014, 104 badgers were tested for the presence of Mycobacterium tuberculosis complex bacteria as part of a joint project between the DWHC and the Central Veterinary institute in Lelystad; all samples were negative (for more details see the published study results: https://www.dwhc.nl/en/geen-tbc-dassen-nederland/).
External information
Research results
Projects
No projects found.
Overige berichten
No news found.
Publications
No publications found.
