Difference between revisions of "Respiratory Bacterial Infections - Pathology"

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#REDIRECT[[:Category:Respiratory Bacterial Infections]]
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{{toplink
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|backcolour = D1EEEE
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|linkpage =Cardiorespiratory System - Pathology
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|linktext =Cardiorespiratory System
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|maplink = Cardiorespiratory System (Content Map) - Pathology
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|pagetype =Pathology
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|sublink1=Respiratory System Inflammation - Pathology
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|subtext1=RESPIRATORY SYSTEM INFLAMMATION
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}}
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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===
 +
 
 +
*See [[Respiratory Viral Infections - Pathology#In Dogs|Infectious canine tracheitis]]
 +
*Synonym: '''Kennel cough'''
 +
*Multiple agents implicated
 +
 
 +
===Tuberculosis in dogs===
 +
 
 +
*Dogs are rarely susceptible to [[Mycobacteria spp.|''Mycobacterium'' spp.]] causing tuberculosis [[Respiratory Bacterial Infections - Pathology#Tuberculosis|in cattle]], usually either from human or farm animal source
 +
*Gross pathology:
 +
**Multifocal nodules, firm, calcified with necrotic centres
 +
**Usually caudal lung lobes
 +
**Also [[Pleural Cavity & Membranes Inflammatory - Pathology|granulomatous pleuritis]] and [[Pleural Cavity & Membranes Degenerative - Pathology#Haemothorax|haemothorax]]
 +
 
 +
===Nocardiosis===
 +
 
 +
*Caused by [[Actinomycetes|''Nocardia'']]
 +
*Grossly:
 +
**Haemorrhagic purulent exudate in [[Pleural Cavity & Membranes Inflammatory - Pathology|pleural cavity]]
 +
**Yellow granules on pleural surface
 +
*Possibly caused by penetrating awns of grass
 +
*Mainly in sporting breeds
 +
 
 +
==In Cats==
 +
 
 +
===Feline Chlamydiosis===
 +
 
 +
*Persistent respiratory infection caused by [[Chlamydia and Chlamydophila species|''Chlamydia psittaci (felis)'']]
 +
*Mild conjunctivitis, serous purulent [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]] and conjunctivitis, in severe cases mild [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]] - feline pneumonitis
 +
 
 +
===[[Mycoplasmas|''Mycoplasma felis'']]===
 +
 
 +
*Can also cause mild respiratory infection
 +
 
 +
==In Horses==
 +
 
 +
*[http://www.ivis.org/special_books/Lekeux/chanter/chapter_frm.asp?LA=1 Overview of equine respiratory disease] by N Chanter of the Animal Health Trust, taken from Equine respiratory diseases edited by P Lekeux. Chapters of this book are published by the International Veterinary Information Service (IVIS)
 +
 
 +
===Strangles===
 +
 
 +
*Caused by very pathogenic [[Streptococci|''Streptococcus equi subsp. equi'']]
 +
*Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
 +
*''Streptococcus zooepidemicus'' and ''S. equisimilis'' are usually non-pathogenic
 +
*Typically [[Nasal cavity - inflammatory#Infectious causes of rhinitis|suppurative rhinitis]], [[Nasopharynx - inflammatory#Infectious causes of pharyngitis|pharyngitis]] and '''lymphadenitis''' of the lymph nodes of the head and neck that drain the upper respiratory tract, these lymph nodes often rupture and discharge pus 2-3 weeks after the onset of infection
 +
*Infection with ''Streptococcus equi'' occurs after contact with contaminated feed, water bowls or an infected carrier [[Hindgut Fermenters - Horse - Anatomy & Physiology|horse]]
 +
*Organism remains viable in environment for months
 +
*Possibility of other sources of infection - in pharynx of in-contact dogs?, guttural pouches of persistently infected horses
 +
*Attaches to nasopharyngeal epithelial cells, then mucosa, lymphatics and lymph nodes
 +
*Multiplies extra-cellularly
 +
*Gross pathology
 +
**Initial bilateral nasal discharge, serous becoming purulent
 +
**Catarrhal conjunctivitis may be present
 +
*Less frequently, complications can occur as follows :
 +
**Purulent inflammation may extent to [[Guttural pouches - inflammatory|guttural pouches]] or [[Lungs - inflammatory#Infectious causes of pneumonia|lungs]], [[Paranasal Sinuses Inflammatory - Pathology#Infectious causes of sinusitis|sinusitis]]
 +
**Bacteraemia with metastatic abscesses - most often to the mesenteric and mediastinal lymph nodes, less frequently, other organs such as [[Liver - Anatomy & Physiology|liver]], kidney and brain can be involved - '''Bastard strangles'''
 +
**Retropharyngeal abscesses can rupture onto the skin of neck or into the [[Guttural pouches - inflammatory|guttural pouch]] resulting in '''guttural pouch empyema or chondroid formation''' - carrier state
 +
**[[Muscles - degenerative#Ischaemia|'''Purpura haemorrhagica''']]: an acute vasculitis causing urticaria and extensive oedema of ventrum, head and distal limbs
 +
**[[Larynx - degenerative#Laryngeal hemiplegia|Laryngeal hemiplegia]] due to enlarged retropharyngeal lymph nodes
 +
**Compression of cranial nerves
 +
 
 +
*Interview with Professors Josh Slater and Ken Smith providing an interesting insight into the pathogenesis, prevalence and possible prevention of ''Streptococcus equi'' infections in horses - listen to [http://www.rvc.ac.uk/Review/Podcasts/RVC_Podcast_12.m4a Strangles podcast]
 +
 
 +
===''Streptococcus equi subsp. zooepidemicus''===
 +
*Causative agent [[Streptococci|''Streptococcus equi subsp. zooepidemicus'']]
 +
*Can infect the respiratory tract ([[Nasal cavity - inflammatory#Infectious causes of rhinitis|nasal cavity]], [[Paranasal Sinuses Inflammatory - Pathology#Infectious causes of sinusitis|paranasal sinuses]], [[Trachea - inflammatory#Infectious causes of tracheitis|trachea]] and [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchi/bronchioles]])
 +
*URT infection can be indistinguishable clinically from Strangles, but does not cause suppurative lymphadenitis (cf: ''S.equi subsp. equi'')
 +
 
 +
===Glanders===
 +
 
 +
*Caused by [[Pseudomonas aeruginosa and Burkholderia species|''Burkholderia (Pseudomonas) mallei'']]
 +
*Exists in eastern Europe and Asia
 +
*Notifiable in UK
 +
*Characterised by multiple small submucosal [[Nasal cavity - inflammatory#Infectious causes of rhinitis|nasal nodules]] which liquefy and ulcerate
 +
**Cores of neutrophils surrounded by a rim of macrophages and [[General Pathology - Chronic Inflammation#Granulation tissue|granulation tissue]]
 +
*In addition may have similar nodules in [[Lungs - inflammatory#Infectious causes of pneumonia|lungs]], '''lymph nodes''' and '''cutaneous lymphatics''' 
 +
*Clinical signs: fever and head/ neck lymphadenitis, [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]]
 +
 
 +
===''Rhodococcus equi''===
 +
[[Image:Pyogranulomatous lungs due to Rhodococcus Equi.jpg|right|thumb|100px|<small><center>Pyogranulomatous lesions due to Rhodococcus equi (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
 
 +
*Causative agent [[Rhodococcus equi|''Rhodococcus (Corynebacterium) equi'']]
 +
*Important cause of sever, often fatal [[Lungs - inflammatory#Granulomatous pneumonia|granulomatous]] [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] in foals
 +
*Clinical signs include depression, cough, weight loss, respiratory distress, diarrhoea, arthritis, subcutaneous abscesses
 +
*Bacterium survives phagocytosis and multiplies
 +
*Bacterial toxins -> caseous necrosis in lungs -> attracts inflammatory cells -> pyogranulomatous pneumonia
 +
*Grossly:
 +
**Multiple firm nodules, usually no encapsulation
 +
**Partial [[Lungs - ventilation#Atelectasis (Collapse)|atelectasis]]
 +
*Histologically:
 +
**Pyogranulomatous lesions
 +
**Macrophages with ingested microorganisms in the alveoli
 +
**Necrosis spreading through parenchyma
 +
 
 +
==In Cattle==
 +
 
 +
===Necrotic laryngitis===
 +
[[Image:Necrotising laryngitis.jpg|right|thumb|100px|<small><center>Necrotising laryngitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
[[Image:Tracheitis in calf diphtheria.jpg|right|thumb|100px|<small><center>Tracheitis in calf diphtheria (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
 
 +
*Synonyms: '''laryngeal diphtheria, calf diphtheria'''
 +
*Common disease in cattle, and can occur in swine
 +
*Caused by infection with [[Fusobacterium|''Fusobacterium necrophorum'']] 
 +
*Lesions may also be found in other parts of the [[Nasopharynx - inflammatory#Infectious causes of pharyngitis|oropharynx]] 
 +
*The bacterium usually gains entry through damaged mucosal surfaces e.g. after viral infections or injury following (poor!) use of dosing guns, coarse poor quality roughage
 +
*Results in severe acute neutrophilic [[Larynx - inflammatory#Infectious causes of laryngitis|laryngitis]]
 +
*Extensive accumulation of fibrin and necrotic cellular debris on the ulcerated mucosal surface
 +
*Lesions appear as dry plaques of fibrinonecrotic exudate and ulceration on the laryngeal mucosa
 +
*Inhalation of exudate and bacterial organisms may cause [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]]
 +
*Death may result from toxaemia or asphyxiation
 +
*Also may occur in pigs
 +
 
 +
===''CAR bacillus''===
 +
 
 +
*Causative agent: [[Bacillus species|''Cillia-associated respiratory bacillus'']]
 +
*An unclassified bacteria that can't be grown in culture
 +
*Colonises ciliated epithelium in '''rodents''' and ruminants
 +
*Associated with [[Nasal cavity - inflammatory#Infectious causes of rhinitis|chronic lymphocytic rhinitis]], [[Trachea - inflammatory#Infectious causes of tracheitis|tracheitis]] and [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchitis]]
 +
*Clinical disease in '''rabbits''' and '''rodents'''
 +
*Subclinical disease in ruminants
 +
 
 +
===Pneumonic pasteurellosis===
 +
 
 +
*Synonym: '''Shipping fever'''
 +
*Caused by [[Pasteurella species and Mannheimia haemolytica|''Manheimia haemolytica'' biotype A serotype 1 (90%) and ''Pasteurella multocida'']]
 +
*In young, growing cattle
 +
*In clinically normal cattle ''Mann. haemolytica'' serotype 2 is present in low numbers, only in nasal cavity and tonsils
 +
*Clinical signs: depression, anorexia, rapid shallow respiration, crusty nose with mucopurulent discharge, serous ocular discharge
 +
*Acute [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchopneumonia]] and may progress to [[Lungs - inflammatory#Lobar pneumonia|lobar pneumonia]] with toxaemia
 +
*Pathology
 +
**Lobar, cranioventral exudative pneumonia with fibrin, [[Pleural Cavity & Membranes Inflammatory - Pathology|fibrinous pleuritis]], areas of coagulative necrosis
 +
*Histology
 +
**Large numbers of bacteria are usually associated with necrotic lesions
 +
 
 +
===Tuberculosis===
 +
[[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>]]
 +
 
 +
*Caused by [[Mycobacteria spp.|''Mycobacteruim bovis'' and ''M. tuberculosis'']]
 +
*Reside primarily within macrophages where they multiply and result in characteristic [[Lungs - inflammatory#Granulomatous pneumonia|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 - inflammatory|trachea]] and [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchi]] due to coughed up bacteria
 +
***Spreads into [[Pleural Cavity & Membranes Inflammatory - Pathology|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
 +
 
 +
===Contagious bovine pleuropneumonia (CBPP)===
 +
[[Image:Contagious bovine pleuropneumonia.jpg|right|thumb|100px|<small><center>Contagious bovine pleuropneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
 
 +
*Caused by [[Mycoplasmas|''Mycoplasma mycoides'']], small colony variant
 +
*Causes a fibrinonecrotic [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] and [[Pleural Cavity & Membranes Inflammatory - Pathology|fibrinous pleuritis]]
 +
*Also affects caudodorsal areas
 +
*[[Lungs - inflammatory#Bronchopneumonia|Bronchopneumonia]] -> [[Lungs - inflammatory#Lobar pneumonia|lobar pneumonia]]
 +
*Sequestra are common
 +
*NB: similarity to pneumonic pasteurellosis but CBPP has more pronounced marbled effect
 +
*Interstitial septa are markedly widened by fibrinous exudate and the necrotic areas may have a fibrous capsule
 +
*Large colony variant will cause a similar disease in goats
 +
 
 +
===Enzootic pneumonia of calves===
 +
[[Image:Acute suppurative pneumonia.jpg|right|thumb|100px|<small><center>Acute suppurative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
[[Image:Calf pneumonia.jpg|right|thumb|100px|<small><center>Calf pneumonia - chronic, with abscesses, fibrosis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
 
 +
*Range of infectious agents together with managemental and environmental stress cause damage to the respiratory tract
 +
*Causes unthriftiness in animals < 6 months old
 +
*Usually the primary pathogen is a virus, secondary pathogens are bacteria and mycoplasmas
 +
*Pathogens:
 +
**[[Mycoplasmas|''Mycoplasmas'']]
 +
***Mycoplasmal [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchitis]] and [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] of calves is an important component of the syndrome of enzootic pneumonia
 +
***On its own causes Mycoplasmal ("Cuffing") pneumonia responsible for [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchitis and bronchiolitis]] and [[Lungs - inflammatory#Infectious causes of pneumonia|bronchointerstitial pneumonia]]
 +
***It is thought to pick up host antigens in order to prevent recognition by the body defences as foreign
 +
***In uncomplicated mycoplasma infection, the lesions are generally mild and consist of patchy red/purple areas of [[Lungs - ventilation#Atelectasis|atelectasis]] in the '''cranio-ventral lung lobes'''
 +
***More confluent areas can develop with an underlying bronchointestitial pneumonia and resulting atelectasis
 +
***''M. bovis''
 +
****Most pathogenic
 +
****Widespread lymphofollicular accumulations which contain germinal centres develop more slowly
 +
****These lesions can result in narrowing of the bronchiolar lumina - this is the classical lesion of '''‘cuffing pneumonia’'''
 +
***''M. dispar''
 +
***''Ureaplasma'' sp.
 +
**Viruses
 +
***[[Respiratory Viral Infections - Pathology#Respiratory syncytial virus|Bovine respiratory syncytial virus (BRSV)]] - can be primary, causes suppression of pulmonary immune response
 +
***[[Respiratory Viral Infections - Pathology#Parainfluenza- 3|Parainfluenza- 3 (PI3)]] - can be primary, causes suppression of pulmonary immune response
 +
***[[Flaviviridae|Bovine viral diarrhoea virus (BVDV)]] - suppression of pulmonary immune response
 +
***[[Adenoviridae|Adenoviruses]]
 +
***[[Coronaviridae|Calf coronavirus]]
 +
***[[Respiratory Viral Infections - Pathology#Infectious bovine rhinotracheitis (IBR)|Bovine herpes viruses]]
 +
**Bacteria
 +
***[[Pasteurella species and Mannheimia haemolytica|''Manheimia (Pasteurella) haemolytica'' serotype A1]]
 +
***[[Pasteurella species and Mannheimia haemolytica|''Pasteurella multocida'']]
 +
***[[Arcanobacter pyogenes|''Arcanobacter pyogenes'']]
 +
***[[Haemophilus species|''Haemophilus sommus'']]
 +
*All transmitted by aerosol and direct contact
 +
*Gross pathology:
 +
**Consolidation of the cranioventral areas which increases in volume with duration
 +
**On cut surface, exudate in the main airway of affected lobules with thickening of the surrounding connective tissue
 +
*Micro pathology:
 +
**Substantial lymphoid tissue around the airways
 +
**Even to proper follicle formation, some of which may be large enough to compress the lumen
 +
**Mixed cell exudate in the airway lumen
 +
**Partial alveolar collapse distal to the compression
 +
**Alveolar exudate contains a mixture of inflammatory cells
 +
**Slight thickening of the alveolar walls with lymphocytes
 +
 
 +
===Acute exudative pneumonia===
 +
 
 +
*[[Lungs - inflammatory#Infectious causes of pneumonia|Pneumonia]] in very young calves
 +
*[[Arcanobacter pyogenes|''Arcanobacter pyogenes'']] is most frequently isolated
 +
*Cranio-ventral distribution
 +
 
 +
==In Sheep==
 +
 
 +
===Laryngeal chondritis===
 +
[[Image:Oedema and chondritis in larynx of sheep.jpg|right|thumb|100px|<small><center>Oedema and chondritis in larynx of sheep (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 +
 
 +
*Caused by [[Fusobacterium|''Fusobacterium necrophorum'']] 
 +
*[[Larynx - inflammatory#Infectious causes of laryngitis|Infection of laryngeal cartilages]]
 +
*Can be seen in short-necked breed, e.g. Texels, East Friesians and Southdowns
 +
*Leads to extreme respiratory distress
 +
*Laryngeal mucosa is necrotic and ulcerated
 +
*Associated with [[Larynx - degenerative#Laryngeal oedema|laryngeal oedema]]
 +
*Also may occur in young [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]] and calves
 +
 
 +
===''CAR bacillus''===
 +
 
 +
*As [[Respiratory Bacterial Infections - Pathology#CAR bacillus|in cattle]]
 +
 
 +
===Enzootic pneumonia of lambs===
 +
 
 +
*Caused by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella (Manheimia) haemolytica'']], possibly together with [[Mycoplasmas|''Mycoplasma ovipneumoniae'']]
 +
*Mainly in late spring/early summer after environmental stress i.e. handling or moving
 +
*May be acute with producing a fibrinonecrotic [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] and associated [[Pleural Cavity & Membranes Inflammatory - Pathology|pleuritis]]
 +
*Or tending towards chronicity with abscessation and fibrous pleural adhesions
 +
*A septicaemic form (mortality 5%) is reported to follow the stress of movement to new pasture in the autumn in weaned lambs.
 +
*Foci of necrosis containing many bacteria are seen at the site of initial invasion in the pharynx and in the '''[[Liver - Anatomy & Physiology|liver]]'''
 +
*Meningitis in young lambs and mastitis in ewes are other expressions
 +
 
 +
===Melioidosis (Pseudoglanders)===
 +
 
 +
*Caused by [[Pseudomonas aeruginosa and Burkholderia species|''Pseudomonas (Malleomyces) pseudomallei'']], Closely related to [[Respiratory Bacterial Infections - Pathology#Glanders|''P. mallei'']] in [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]]
 +
*Causes disease in sheep, goats and pigs, occasionally other species
 +
*Starts as a pyemia and localises in varius tissues, including the lung as abscessation
 +
**Encapsulated abscesses contain yellow, caseous or creamy pus
 +
*[[Lungs - inflammatory#Infectious causes of pneumonia|Pneumonia]] and arthritis are the most common presentation
 +
 
 +
==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 and Bordetella avium|''Bordetella bronchiseptica'']]
 +
***Appears to facilitate colonisation of nasal epithelium by the toxigenic ''Pasteurella''
 +
**Toxin-producing strain of [[Pasteurella species and Mannheimia haemolytica|
 +
''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#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 species and Mannheimia haemolytica|''P.multocida'']] adheres poorly to mucous membranes, and therefore requires a predisposing nasal insult to assist colonisation eg: co-infection with [[Bordetella bronchiseptica and Bordetella avium|''B.bronchoseptica'']] 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 and Bordetella avium|''B.bronchoseptica'']] strains alone, that carry a gene that encodes for a dermonecrotic toxin.
 +
***Turbinate bone can regenerate by the time of slaughter
 +
 
 +
*[[Bordetella bronchiseptica and Bordetella avium|''Bordetella bronchiseptica'']] also causes [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#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 [[Mycoplasmas|''Mycoplasma hyopneumoniae'']] and [[Mycoplasmas|''M. hyorhinis'']]
 +
*Also called '''mycoplasmal pneumonia'''
 +
*Major cause of unthriftiness in young pigs
 +
*[[Lungs - inflammatory#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 species and Mannheimia haemolytica|''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#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 species|''Actinobacillus pleuropneumoniae'']]
 +
*Expolsive outbreaks of [[Lungs - inflammatory#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 species and Mannheimia haemolytica|''Pasteurella multocida'']] can cause a severe acute fibrinous [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] in pigs
 +
*The most significant disease here is that caused by ''P. multocida'' secondary to underlying [[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#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 species|''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#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#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 species|''Haemophilus parasuis'']]
 +
*May cause suppurative [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#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 [[Streptococci|''Streptococcus suis'' type II]]
 +
*Zoonotic
 +
*Carried in nasal cavity and lymph nodes of healthy pigs
 +
*Some serotypes may cause [[Lungs - inflammatory#Embolic pneumonia|embolic pneumonia]], others suppurative or fibrinous [[Lungs - inflammatory#Bronchopneumonia|bronchopneumonia]], often in combination with other bacteria
 +
 
 +
===Tuberculosis in pigs===
 +
 
 +
*Pigs are susceptible to the [[Mycobacteria spp.|''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 species and Mannheimia haemolytica|''Pasteurella multocida'']], less commonly and/or [[Bordetella bronchiseptica and Bordetella avium|''B.bronchoseptica'']]
 +
*Clinical signs (nasal discharge, sneezing) result from an acute to chronic [[Nasal cavity - inflammatory|rhinitis]]
 +
 
 +
===''CAR bacillus''===
 +
 
 +
*As [[Respiratory Bacterial Infections - Pathology#CAR bacillus|in cattle]]

Revision as of 22:35, 31 July 2008

WikiPathWikiPath Banner.png
()Map CARDIORESPIRATORY SYSTEM (Map)
RESPIRATORY SYSTEM INFLAMMATION



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 in dogs

Nocardiosis

  • Caused by Nocardia
  • Grossly:
    • Haemorrhagic purulent exudate in pleural cavity
    • Yellow granules on pleural surface
  • Possibly caused by penetrating awns of grass
  • Mainly in sporting breeds

In Cats

Feline Chlamydiosis

Mycoplasma felis

  • Can also cause mild respiratory infection

In Horses

  • Overview of equine respiratory disease by N Chanter of the Animal Health Trust, taken from Equine respiratory diseases edited by P Lekeux. Chapters of this book are published by the International Veterinary Information Service (IVIS)

Strangles

  • Caused by very pathogenic Streptococcus equi subsp. equi
  • Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
  • Streptococcus zooepidemicus and S. equisimilis are usually non-pathogenic
  • Typically suppurative rhinitis, pharyngitis and lymphadenitis of the lymph nodes of the head and neck that drain the upper respiratory tract, these lymph nodes often rupture and discharge pus 2-3 weeks after the onset of infection
  • Infection with Streptococcus equi occurs after contact with contaminated feed, water bowls or an infected carrier horse
  • Organism remains viable in environment for months
  • Possibility of other sources of infection - in pharynx of in-contact dogs?, guttural pouches of persistently infected horses
  • Attaches to nasopharyngeal epithelial cells, then mucosa, lymphatics and lymph nodes
  • Multiplies extra-cellularly
  • Gross pathology
    • Initial bilateral nasal discharge, serous becoming purulent
    • Catarrhal conjunctivitis may be present
  • Less frequently, complications can occur as follows :
    • Purulent inflammation may extent to guttural pouches or lungs, sinusitis
    • Bacteraemia with metastatic abscesses - most often to the mesenteric and mediastinal lymph nodes, less frequently, other organs such as liver, kidney and brain can be involved - Bastard strangles
    • Retropharyngeal abscesses can rupture onto the skin of neck or into the guttural pouch resulting in guttural pouch empyema or chondroid formation - carrier state
    • Purpura haemorrhagica: an acute vasculitis causing urticaria and extensive oedema of ventrum, head and distal limbs
    • Laryngeal hemiplegia due to enlarged retropharyngeal lymph nodes
    • Compression of cranial nerves
  • Interview with Professors Josh Slater and Ken Smith providing an interesting insight into the pathogenesis, prevalence and possible prevention of Streptococcus equi infections in horses - listen to Strangles podcast

Streptococcus equi subsp. zooepidemicus

Glanders

  • Caused by Burkholderia (Pseudomonas) mallei
  • Exists in eastern Europe and Asia
  • Notifiable in UK
  • Characterised by multiple small submucosal nasal nodules which liquefy and ulcerate
  • In addition may have similar nodules in lungs, lymph nodes and cutaneous lymphatics
  • Clinical signs: fever and head/ neck lymphadenitis, rhinitis

Rhodococcus equi

Pyogranulomatous lesions due to Rhodococcus equi (Image sourced from Bristol Biomed Image Archive with permission)
  • Causative agent Rhodococcus (Corynebacterium) equi
  • Important cause of sever, often fatal granulomatous pneumonia in foals
  • Clinical signs include depression, cough, weight loss, respiratory distress, diarrhoea, arthritis, subcutaneous abscesses
  • Bacterium survives phagocytosis and multiplies
  • Bacterial toxins -> caseous necrosis in lungs -> attracts inflammatory cells -> pyogranulomatous pneumonia
  • Grossly:
    • Multiple firm nodules, usually no encapsulation
    • Partial atelectasis
  • Histologically:
    • Pyogranulomatous lesions
    • Macrophages with ingested microorganisms in the alveoli
    • Necrosis spreading through parenchyma

In Cattle

Necrotic laryngitis

Necrotising laryngitis (Image sourced from Bristol Biomed Image Archive with permission)
Tracheitis in calf diphtheria (Image sourced from Bristol Biomed Image Archive with permission)
  • Synonyms: laryngeal diphtheria, calf diphtheria
  • Common disease in cattle, and can occur in swine
  • Caused by infection with Fusobacterium necrophorum
  • Lesions may also be found in other parts of the oropharynx
  • The bacterium usually gains entry through damaged mucosal surfaces e.g. after viral infections or injury following (poor!) use of dosing guns, coarse poor quality roughage
  • Results in severe acute neutrophilic laryngitis
  • Extensive accumulation of fibrin and necrotic cellular debris on the ulcerated mucosal surface
  • Lesions appear as dry plaques of fibrinonecrotic exudate and ulceration on the laryngeal mucosa
  • Inhalation of exudate and bacterial organisms may cause bronchopneumonia
  • Death may result from toxaemia or asphyxiation
  • Also may occur in pigs

CAR bacillus

Pneumonic pasteurellosis

  • Synonym: Shipping fever
  • Caused by Manheimia haemolytica biotype A serotype 1 (90%) and Pasteurella multocida
  • In young, growing cattle
  • In clinically normal cattle Mann. haemolytica serotype 2 is present in low numbers, only in nasal cavity and tonsils
  • Clinical signs: depression, anorexia, rapid shallow respiration, crusty nose with mucopurulent discharge, serous ocular discharge
  • Acute bronchopneumonia and may progress to lobar pneumonia with toxaemia
  • Pathology
    • Lobar, cranioventral exudative pneumonia with fibrin, fibrinous pleuritis, areas of coagulative necrosis
  • Histology
    • Large numbers of bacteria are usually associated with necrotic lesions

Tuberculosis

Tuberculosis caused by M. bovis (Image sourced from Bristol Biomed Image Archive with permission)
  • Caused by Mycobacteruim 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

Contagious bovine pleuropneumonia (CBPP)

Contagious bovine pleuropneumonia (Image sourced from Bristol Biomed Image Archive with permission)
  • Caused by Mycoplasma mycoides, small colony variant
  • Causes a fibrinonecrotic pneumonia and fibrinous pleuritis
  • Also affects caudodorsal areas
  • Bronchopneumonia -> lobar pneumonia
  • Sequestra are common
  • NB: similarity to pneumonic pasteurellosis but CBPP has more pronounced marbled effect
  • Interstitial septa are markedly widened by fibrinous exudate and the necrotic areas may have a fibrous capsule
  • Large colony variant will cause a similar disease in goats

Enzootic pneumonia of calves

Acute suppurative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)
Calf pneumonia - chronic, with abscesses, fibrosis (Image sourced from Bristol Biomed Image Archive with permission)
  • Range of infectious agents together with managemental and environmental stress cause damage to the respiratory tract
  • Causes unthriftiness in animals < 6 months old
  • Usually the primary pathogen is a virus, secondary pathogens are bacteria and mycoplasmas
  • Pathogens:
  • All transmitted by aerosol and direct contact
  • Gross pathology:
    • Consolidation of the cranioventral areas which increases in volume with duration
    • On cut surface, exudate in the main airway of affected lobules with thickening of the surrounding connective tissue
  • Micro pathology:
    • Substantial lymphoid tissue around the airways
    • Even to proper follicle formation, some of which may be large enough to compress the lumen
    • Mixed cell exudate in the airway lumen
    • Partial alveolar collapse distal to the compression
    • Alveolar exudate contains a mixture of inflammatory cells
    • Slight thickening of the alveolar walls with lymphocytes

Acute exudative pneumonia

In Sheep

Laryngeal chondritis

Oedema and chondritis in larynx of sheep (Image sourced from Bristol Biomed Image Archive with permission)

CAR bacillus

Enzootic pneumonia of lambs

  • Caused by Pasteurella (Manheimia) haemolytica, possibly together with Mycoplasma ovipneumoniae
  • Mainly in late spring/early summer after environmental stress i.e. handling or moving
  • May be acute with producing a fibrinonecrotic bronchopneumonia and associated pleuritis
  • Or tending towards chronicity with abscessation and fibrous pleural adhesions
  • A septicaemic form (mortality 5%) is reported to follow the stress of movement to new pasture in the autumn in weaned lambs.
  • Foci of necrosis containing many bacteria are seen at the site of initial invasion in the pharynx and in the liver
  • Meningitis in young lambs and mastitis in ewes are other expressions

Melioidosis (Pseudoglanders)

  • Caused by Pseudomonas (Malleomyces) pseudomallei, Closely related to P. mallei in horses
  • Causes disease in sheep, goats and pigs, occasionally other species
  • Starts as a pyemia and localises in varius tissues, including the lung as abscessation
    • Encapsulated abscesses contain yellow, caseous or creamy pus
  • Pneumonia and arthritis are the most common presentation

In Pigs

Atrophic Rhinitis

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.bronchoseptica 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 B.bronchoseptica strains alone, that carry a gene that encodes for a dermonecrotic toxin.
      • Turbinate bone can regenerate by the time of slaughter

Necrotic laryngitis in pigs

Enzootic pneumonia of pigs

Enzootic pneumonia of pigs(Image sourced from Bristol Biomed Image Archive with permission)
  • Caused by Mycoplasma hyopneumoniae and M. hyorhinis
  • Also called mycoplasmal pneumonia
  • Major cause of unthriftiness in young pigs
  • Pneumonia in weaned pigs
  • Cough, reduced growth rate
  • Attached to cilia - no mucociliary clearance
  • Usually non-fatal unless there is secondary infection (e.g. 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 bronchointerstitial pneumonia
    • In chronic cases, prominent accumulations of lymphoid cells can be seen around airways and blood vessels

Actinobacillus pleuropneumoniae

Pasteurellosis in pigs

Contagious porcine pleuropneumonia

  • Caused by 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 bronchopneumonia with 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

Streptococcal pneumonia

Tuberculosis in pigs

  • Pigs are susceptible to the Mycobacterium spp. causing 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

CAR bacillus