Difference between revisions of "Respiratory Bacterial Infections - Pathology"

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#REDIRECT[[:Category:Respiratory Bacterial Infections]]
 
 
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|backcolour = D1EEEE
 
|linkpage =Cardiorespiratory System - Pathology
 
|linktext =Cardiorespiratory System
 
|maplink = Cardiorespiratory System (Content Map) - Pathology
 
|pagetype =Pathology
 
|sublink1=Respiratory System Inflammation - Pathology
 
|subtext1=RESPIRATORY SYSTEM INFLAMMATION
 
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<br>
 
==In general==
 
 
 
*Main clinical expression is as secondary invaders of previously damaged lung tissue due to viral or parasitic involvement or environmental stress
 
*Some are initial pathogens in their own right while others can damage the tract allowing invasion by more pathogenic types
 
 
 
==In Dogs==
 
[[Infectious Canine Tracheitis]]
 
 
 
===[[Tuberculosis - Dogs]]===
 
 
 
 
 
===[[Nocardiosis]]===
 
 
 
==In Cats==
 
 
 
===[[Chlamydiosis, Feline]] ===
 
 
 
 
 
===''[[Mycoplasma felis]]''===
 
 
 
==In Horses==
 
 
 
===[[Strangles]]===
 
 
 
===''[[Streptococcus equi subsp. zooepidemicus]]''===
 
 
 
===[[Glanders]]===
 
 
 
 
 
===''[[Rhodococcus equi]]''===
 
 
 
==In Cattle==
 
 
 
===[[Necrotic Laryngitis]]===
 
 
 
[[Cillia-associated Respiratory Bacillus]]
 
 
 
===[[Pneumonic Pasteurellosis]]===
 
 
 
===[[Tuberculosis - Cattle]]===
 
 
 
 
 
===[[Contagious Bovine Pleuropneumonia]] ===
 
 
 
 
 
 
 
 
 
===[[Enzootic Pneumonia - Calves]]===
 
 
 
 
 
===[[Acute Exudative Pneumonia]]===
 
 
 
==In Sheep==
 
 
 
===[[Laryngeal Chondritis]]===
 
 
 
===''CAR bacillus''===
 
 
 
*As [[Respiratory Bacterial Infections - Pathology#CAR bacillus|in cattle]]
 
 
 
===[[Enzootic Pneumonia - Lambs]]===
 
 
 
 
 
===[[Melioidosis]] ===
 
 
 
==In Pigs==
 
 
 
===Atrophic Rhinitis===
 
[[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]]
 
 
 
===Necrotic laryngitis in pigs===
 
*As [[Respiratory Bacterial Infections - Pathology#In Cattle|in cattle]]
 
*Caused by infection with [[Fusobacterium|''Fusobacterium necrophorum'']]
 
 
 
===Enzootic pneumonia of pigs===
 
[[Image:Enzootic pneumonia of pigs.jpg|right|thumb|100px|<small><center>Enzootic pneumonia of pigs(Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 
 
 
*Caused by ''[[Mycoplasma hyopneumoniae]]'' and ''[[Mycoplasma hyorhinis]]''
 
*Also called '''mycoplasmal pneumonia'''
 
*Major cause of unthriftiness in young pigs
 
*[[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|Pneumonia]] in weaned pigs
 
*Cough, reduced growth rate
 
*Attached to cilia - no [[Respiratory System General Introduction - Pathology#Mucociliary escalator|mucociliary clearance]]
 
*Usually non-fatal unless there is secondary infection (e.g. [[Pasteurella multocida|''Pasteurella multocida'']])
 
*Gross pathology:
 
**Confluent consolidation of the cranioventral lung lobes
 
**In other areas there may be small red to grey focal lesions evident which indicate the bronchiolar orientation of the inflammatory process
 
*Histologically
 
**Changes result from a catarrhal [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
 
**In chronic cases, prominent accumulations of lymphoid cells can be seen around airways and blood vessels
 
 
 
===''Actinobacillus pleuropneumoniae''===
 
 
 
*Causative agent: ''[[Actinobacillus pleuropneumoniae]]''
 
*Expolsive outbreaks of [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
 
*Spread by direct contact and aerosol
 
*Lesions
 
**Largely from toxin produced
 
**In diphragmatic lobes of the lungs
 
*Haemorrhage with [[Pleural Cavity & Membranes Inflammatory - Pathology|fibrinous pleuritis]]
 
*Usually localised, sometimes generalised
 
 
 
===Pasteurellosis in pigs===
 
 
 
*[[Pasteurella multocida|''Pasteurella multocida'']] can cause a severe acute fibrinous [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] in pigs
 
*The most significant disease here is that caused by ''P. multocida'' secondary to underlying [[:Category:Mycoplasmas|''mycoplasma'' pneumonia]], see above [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of pigs|enzootic pneumonia of pigs]]
 
**This results in chronic suppurative [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchopneumonia]]  with abscessation and [[Pleural Cavity & Membranes Inflammatory - Pathology|pleuritis]]
 
*If there is considerable pleural involvement, it may be indistinguishable from lesions caused by ''[[Haemophilus pleuropneumonia]]'' (below)
 
*Also isolated from cases of meningitis and septicaemia in piglets
 
 
 
===Contagious porcine pleuropneumonia===
 
 
 
*Caused by [[Haemophilus pleuropneumonia|''Haemophilus (Actinobacillus) pleuropneumonia'']]
 
*Seen mainly between 6wks-6mths of age but will affect any age
 
*Highly pathogenic strains are capable of initiating disease on their own with high mortality in young pigs
 
*A fibrinonecrotic [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] with [[Pleural Cavity & Membranes Inflammatory - Pathology|pleurisy]]
 
*Foci of haemorrhagic consolidation or necrosis, mainly around major bronchi, tend to sequestrate
 
*Tending to spread throughout all lung lobes: therefore a cranioventral distribution may not be particularly evident
 
 
 
===Glasser's disease===
 
 
 
*Caused by ''[[Haemophilus parasuis]]''
 
*May cause suppurative [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] and [[Pleural Cavity & Membranes Inflammatory - Pathology|pleuritis]] (as part of polyserositis)
 
*Stress of mixing, weaning and adverse environmental conditions are predisposing to the disease
 
 
 
===Streptococcal pneumonia===
 
 
 
*Caused by ''[[Streptococcus suis]]'' type II
 
 
 
===Tuberculosis in pigs===
 
 
 
*Pigs are susceptible to the [[:Category:Mycobacterium species|''Mycobacterium'' spp.]] causing tuberculosis [[Respiratory Bacterial Infections - Pathology#Tuberculosis|in cattle]]
 
*Rarely extends to lungs after haematogenous spread from ingested bacteria causing tubercles with various degrees of calcification, encapsulation and caseation
 
 
 
==In Rabbits==
 
 
 
===Snuffles===
 
 
 
*Caused by [[Pasteurella multocida|''Pasteurella multocida'']], less commonly and/or ''[[Bordetella bronchiseptica]]''
 
*Clinical signs (nasal discharge, sneezing) result from an acute to chronic [[Nasal Cavity Inflammatory - Pathology|rhinitis]]
 
 
 
===''CAR bacillus''===
 
 
 
*As [[Respiratory Bacterial Infections - Pathology#CAR bacillus|in cattle]]
 

Latest revision as of 10:56, 20 July 2010