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===[[Pneumonic Pasteurellosis]]===
 
===[[Pneumonic Pasteurellosis]]===
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===Tuberculosis===
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===[[Tuberculosis - Cattle]]===
[[Image:Tuberculosis M bovis.jpg|right|thumb|100px|<small><center>Tuberculosis caused by ''M. bovis'' (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Caused by ''[[Mycobacterium bovis]]'' and ''M. tuberculosis''
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*Reside primarily within macrophages where they multiply and result in characteristic [[Lungs Inflammatory - Pathology#Granulomatous pneumonia|granulomatous inflammation]] (macrophages and giant cells, epithelioid cells)
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*Cattle can be infected by inhalation of the organism or through milk
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*'''The primary complex'''
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**Describes the initial focus of infection at the portal of entry (lungs) plus involvement of regional lymph nodes
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**90% of cases exhibit the pulmonary form
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**Grossly:
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***Small tubercles in dorsocaudal subpleural areas which progress to larger confluent areas of caseous necrosis
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***Usually start at bronchio-alveolar junction an progress to the alveoli
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***Caseous lesions, may calcify or be encapsulated
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***Multiple foci may coalesce
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***Ulcers in [[Trachea Inflammatory - Pathology|trachea]] and [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchi]] due to coughed up bacteria
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***Spreads into [[Pleural Cavity & Membranes Inflammatory - Pathology|pleura]]
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**Microscopically:
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***Typical granulomatous inflammation
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***Epitheliod and giant cells at centre of tubercles
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****Macrophages with ingested bacteria, forming epithelioid cells - large vesicular nuclei, abundant pale cytoplasm
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****Giant cells, formed by fusion of macrophages, with multiple nuclei
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***Narrow layer of lymphocytes, mononuclear cells and plasma cells at the periphery of the tubercle
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***With time, peripheral fibroplasia and central necrosis develop
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*If the infection is not contained in the primary complex described above, the mycobacteria can disseminate via lymphatics to other organs and lymph nodes
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*This can allow the development of '''miliary tuberculosis''', i.e. numerous small foci of infection in many organs/ tissues
      
===Contagious bovine pleuropneumonia (CBPP)===
 
===Contagious bovine pleuropneumonia (CBPP)===
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