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==Description==

==Description==

'''Tuberculosis''' in cattle is caused by ''[[Mycobacterium bovis]]''. It is a chronic disease characterised by granulomatous nodular lesions in any organ, although the respiratory system is most commonly affected. The nodules often become necrotic with a caseous centre. The primary lesions may disseminate to involve other body systems.  

'''Tuberculosis''' in cattle is caused by ''[[Mycobacterium bovis]]''. It is a chronic disease characterised by granulomatous nodular lesions in any organ, although the respiratory system is most commonly affected. The nodules often become necrotic with a caseous centre. The primary lesions may disseminate to involve other body systems.  

   

   

Most warm-blooded animals are susceptible to bovine TB and can act as a reservoir for infection. The disease in cattle has been associated with wildlife species in a number of countries; the European badger and red deer in the UK, opossums and ferrets in New Zealand, mule deer, white-tailed deer, elk, and bison in North America and water buffalo in Australia.  

Most warm-blooded animals are susceptible to bovine TB and can act as a reservoir for infection. The disease in cattle has been associated with wildlife species in a number of countries; the European badger and red deer in the UK, opossums and ferrets in New Zealand, mule deer, white-tailed deer, elk, and bison in North America and water buffalo in Australia.  

      

      

==Diagnosis==

==Diagnosis=

The intradermal comparative tuberculin test is widely used in the UK for diagnosis of the disease. Two injections are given subcutaneously in the neck of cattle, one is '''avian''' and the second '''bovine''' '''tuberculin purified protein derivative''' (PPD. The thickness of the skin is recorded at each injection site. The test is read after '''72 hours''', and the thickness of the skin is remeasured. Interpretation is based on finding a swelling or increase in skin thinkness at the site of the injection. A comparison must be made between the reaction to avian and the bovine tuberculin to account for cross reactivity with related diseases, such as atypical mycobacteriosis, or [[Johne's Disease|Johne's disease]].  

The intradermal comparative tuberculin test is widely used in the UK for diagnosis of the disease. Two injections are given subcutaneously in the neck of cattle, one is '''avian''' and the second '''bovine''' '''tuberculin purified protein derivative''' (PPD. The thickness of the skin is recorded at each injection site. The test is read after '''72 hours''', and the thickness of the skin is remeasured. Interpretation is based on finding a swelling or increase in skin thinkness at the site of the injection. A comparison must be made between the reaction to avian and the bovine tuberculin to account for cross reactivity with related diseases, such as atypical mycobacteriosis, or [[Johne's Disease|Johne's disease]]. =

A single intradermal test is used in many countries but has the disadvantage of giving reactors to avian tuberculosis and Johne's disease.

A single intradermal test is used in many countries but has the disadvantage of giving reactors to avian tuberculosis and Johne's disease.

* Dull areas on auscultation of the lungs in advanced cases

* Dull areas on auscultation of the lungs in advanced cases

====Alimentary form====

====Alimentary form===

* Few clinical signs

* Few clinical signs=

* Diarrhoea

* Diarrhoea

* Bloat

* Bloat

Microscopically there are '''epithelioid cells''', with large vesicular nuclei and pale cytoplasm and '''giant cells''', formed by the fusion of macrophages, are found at the centre of tubercles. Surrounding this there is a narrow layer of lymphocytes, mononuclear cells and plasma cells, more advanced cases show peripheral fibroplasia andcentral necrosis.

Microscopically there are '''epithelioid cells''', with large vesicular nuclei and pale cytoplasm and '''giant cells''', formed by the fusion of macrophages, are found at the centre of tubercles. Surrounding this there is a narrow layer of lymphocytes, mononuclear cells and plasma cells, more advanced cases show peripheral fibroplasia andcentral necrosis.

==Treatment==

==Treatment=

Treatment is not usually an option due to the chronic nature of the disease, zoonotic potential and test and slaughter policy.  

Treatment is not usually an option due to the chronic nature of the disease, zoonotic potential and test and slaughter policy.  

Research work continues into the use of vaccination, or a cull strategy for the associated wildlife populations.  

Research work continues into the use of vaccination, or a cull strategy for the associated wildlife populations.  

 

==Prognosis==

==Prognosis==

   

   

==References==

==References==

*Andrews, A.H, Blowey, R.W, Boyd, H and Eddy, R.G. (2004) '''Bovine Medicine''' (Second edition), ''Blackwell Publishing''

 

* Andrews, A.H, Blowey, R.W, Boyd, H and Eddy, R.G. (2004) '''Bovine Medicine''' (Second edition), ''Blackwell Publishing''