Difference between revisions of "Tuberculosis - Cattle"

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(Created page with '[[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></…')
 
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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
 
*If the infection is not contained in the primary complex described above, the mycobacteria can disseminate via lymphatics to other organs and lymph nodes
 
*This can allow the development of '''miliary tuberculosis''', i.e. numerous small foci of infection in many organs/ tissues
 
*This can allow the development of '''miliary tuberculosis''', i.e. numerous small foci of infection in many organs/ tissues
 +
[[Category:Cattle]][[Category:To_Do_-_Clinical]]

Revision as of 14:05, 30 June 2010

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