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→Diagnosis
== 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, an '''avian''' and a '''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 thickness 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 intradermally in the neck of cattle, an '''avian''' and a '''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 thickness 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.
If the mycobacteria disseminated from the primary complex then lymph nodes in other regions will also be affected and there will be multiple small foci of infection on other organs.
If the mycobacteria disseminated from the primary complex then lymph nodes in other regions will also be affected and there will be multiple small foci of infection on other organs.
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 and central 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 and central necrosis.
== Treatment and Control ==
== Treatment and Control ==