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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]]
*Vaccine available
[[Image:Severe atrophic rhinitis.jpg|right|thumb|100px|<small><center>Severe atrophic rhinitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*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|''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
**''''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)]]
***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
*''[[Bordetella bronchiseptica]]'' also causes [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
[[Category:Pig]]