Difference between revisions of "Atrophic Rhinitis"

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(Created page with '*''B. bronchiseptica'' causes Atrophic rhinitis of pigs in association with [[Pasteurella multocida|''Pasteurella mul…')
 
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*Malformation of snout in growing pigs as well as poor growth  
 
*Malformation of snout in growing pigs as well as poor growth  
 
*increases with high stocking density and poor ventilation
 
*increases with high stocking density and poor ventilation
*Vaccine available[[Category:Pig]]
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*Vaccine available
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 +
[[Image:Severe atrophic rhinitis.jpg|right|thumb|100px|<small><center>Severe atrophic rhinitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Atrophy of nasal turbinates and distortion and shortening of the snout 
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*Caused by co-infection of the nasal mucosa with
 +
**''[[Bordetella bronchiseptica]]''
 +
***Appears to facilitate colonisation of nasal epithelium by the toxigenic ''Pasteurella''
 +
**Toxin-producing strain of [[Pasteurella multocida|''Pasteurella multocida'']] capsular type D (or sometimes A)
 +
***Experimental evidence shows that the toxin acts directly on bone cells of the nasal turbinates to cause bone loss, each pathogen can cause atrophy itself but greater damage when together
 +
*Exacerbated by adverse dietary and managemental factors
 +
*In rapidly growing young pigs (4-12 weeks old)
 +
*Clinical signs
 +
**Progressive facial deformity with [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]], catarrhal nasal discharge
 +
**Sneezing, coughing, can progress to dyspnoea and anorexia
 +
 
 +
*Gross pathology
 +
**Overlying skin on shortened snout is thrown into folds
 +
**Deviation of the snout to most affected side
 +
**Various loss of turbinate bone, ventral usually more affected
 +
**Deviation of nasal septum away from affected chamber
 +
**Inflammatory, haemorrhagic and ulcerative lesions in the nasal mucosa
 +
*Micro pathology
 +
**Reduction in the amount of bone in the turbinates
 +
**No osteoid laid down between osteoblasts and existing bone
 +
**Increased fibrous tissue
 +
**Non-specific mucosal inflammation
 +
 
 +
*2 forms of the disease
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**''''Progressive' atrophic rhinitis'''
 +
***Due to infection of the nasal turbinates by P.multocida strains carrying the toxA gene that encodes for an osteolytic toxin. [[Pasteurella multocida|''P.multocida'']] adheres poorly to mucous membranes, and therefore requires a predisposing nasal insult to assist colonisation eg: co-infection with [[Bordetella bronchiseptica|''B.bronchiseptica'']] or [[Cytomegalovirus|Porcine cytomegalovirus (inclusion body rhinitis)]]
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***Turbinate bone atrophy is permanent and progressive
 +
**''''Non-progressive' atrophic rhinitis'''
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***Due to infection of the nasal turbinates by ''[[Bordetella bronchiseptica]]'' strains alone, that carry a gene that encodes for a dermonecrotic toxin.
 +
***Turbinate bone can regenerate by the time of slaughter
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*''[[Bordetella bronchiseptica]]'' also causes [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
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 +
 
 +
 
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[[Category:Pig]]

Revision as of 14:17, 30 June 2010

  • B. bronchiseptica causes Atrophic rhinitis of pigs in association with Pasteurella multocida
  • Colonises nasopharynx
  • Infection must occur during first few weeks of life
  • Produces dermonecrotic toxin which damages osteoblasts, preventing bone formation
  • Leads to turbinate atrophy without distortion of the snout in uncomplicated infections
  • Atrophic rhinitis results when Pasteurella multocida colonises and produces osteolytic toxin, leading to bone resorption
  • Malformation of snout in growing pigs as well as poor growth
  • increases with high stocking density and poor ventilation
  • Vaccine available
Severe atrophic rhinitis (Image sourced from Bristol Biomed Image Archive with permission)
  • Atrophy of nasal turbinates and distortion and shortening of the snout
  • Caused by co-infection of the nasal mucosa with
    • Bordetella bronchiseptica
      • Appears to facilitate colonisation of nasal epithelium by the toxigenic Pasteurella
    • Toxin-producing strain of Pasteurella multocida capsular type D (or sometimes A)
      • Experimental evidence shows that the toxin acts directly on bone cells of the nasal turbinates to cause bone loss, each pathogen can cause atrophy itself but greater damage when together
  • Exacerbated by adverse dietary and managemental factors
  • In rapidly growing young pigs (4-12 weeks old)
  • Clinical signs
    • Progressive facial deformity with rhinitis, catarrhal nasal discharge
    • Sneezing, coughing, can progress to dyspnoea and anorexia
  • Gross pathology
    • Overlying skin on shortened snout is thrown into folds
    • Deviation of the snout to most affected side
    • Various loss of turbinate bone, ventral usually more affected
    • Deviation of nasal septum away from affected chamber
    • Inflammatory, haemorrhagic and ulcerative lesions in the nasal mucosa
  • Micro pathology
    • Reduction in the amount of bone in the turbinates
    • No osteoid laid down between osteoblasts and existing bone
    • Increased fibrous tissue
    • Non-specific mucosal inflammation
  • 2 forms of the disease
    • 'Progressive' atrophic rhinitis
      • Due to infection of the nasal turbinates by P.multocida strains carrying the toxA gene that encodes for an osteolytic toxin. P.multocida adheres poorly to mucous membranes, and therefore requires a predisposing nasal insult to assist colonisation eg: co-infection with B.bronchiseptica or Porcine cytomegalovirus (inclusion body rhinitis)
      • Turbinate bone atrophy is permanent and progressive
    • 'Non-progressive' atrophic rhinitis
      • Due to infection of the nasal turbinates by Bordetella bronchiseptica strains alone, that carry a gene that encodes for a dermonecrotic toxin.
      • Turbinate bone can regenerate by the time of slaughter