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Respiratory Bacterial Infections - Pathology (view source)

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==In general==
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*Main clinical expression is as secondary invaders of previously damaged lung tissue due to viral or parasitic involvement or environmental stress
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*Some are initial pathogens in their own right while others can damage the tract allowing invasion by more pathogenic types
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==In Dogs==
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===Infectious canine tracheitis===
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*See [[Respiratory Viral Infections - Pathology#In Dogs|Infectious canine tracheitis]]
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*Synonym: '''Kennel cough'''
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*Multiple agents implicated
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===Tuberculosis in dogs===
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*Dogs are rarely susceptible to [[Mycobacteria spp.|''Mycobacterium'' spp.]] causing tuberculosis [[Bacterial infections#Tuberculosis|in cattle]], usually either from human or farm animal source
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*Gross pathology:
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**Multifocal nodules, firm, calcified with necrotic centres
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**Usually caudal lung lobes
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**Also [[Pleural cavity and membranes - inflammatory|granulomatous pleuritis]] and [[Pleural cavity and membranes - degenerative#Haemothorax|haemothorax]]
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===Nocardiosis===
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*Caused by [[Actinomycetes|''Nocardia'']]
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*Grossly:
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**Haemorrhagic purulent exudate in [[Pleural cavity and membranes - inflammatory|pleural cavity]]
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**Yellow granules on pleural surface
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*Possibly caused by penetrating awns of grass
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*Mainly in sporting breeds
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==In Cats==
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===Feline Chlamydiosis===
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*Persistent respiratory infection caused by [[Chlamydia and Chlamydophila species|''Chlamydia psittaci (felis)'']]
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*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
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===[[Mycoplasmas|''Mycoplasma felis'']]===
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*Can also cause mild respiratory infection
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==In Horses==
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*[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)
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===Strangles===
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*Caused by very pathogenic [[Streptococci|''Streptococcus equi subsp. equi'']]
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*Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
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*''Streptococcus zooepidemicus'' and ''S. equisimilis'' are usually non-pathogenic
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*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
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*Infection with ''Streptococcus equi'' occurs after contact with contaminated feed, water bowls or an infected carrier [[Hindgut Fermenters - Horse - Anatomy & Physiology|horse]]
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*Organism remains viable in environment for months
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*Possibility of other sources of infection - in pharynx of in-contact dogs?, guttural pouches of persistently infected horses
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*Attaches to nasopharyngeal epithelial cells, then mucosa, lymphatics and lymph nodes
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*Multiplies extra-cellularly
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*Gross pathology
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**Initial bilateral nasal discharge, serous becoming purulent
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**Catarrhal conjunctivitis may be present
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*Less frequently, complications can occur as follows :
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**Purulent inflammation may extent to [[Guttural pouches - inflammatory|guttural pouches]] or [[Lungs - inflammatory#Infectious causes of pneumonia|lungs]], [[Paranasal sinuses - inflammatory#Infectious causes of sinusitis|sinusitis]]
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**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'''
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**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
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**[[Muscles - degenerative#Ischaemia|'''Purpura haemorrhagica''']]: an acute vasculitis causing urticaria and extensive oedema of ventrum, head and distal limbs
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**[[Larynx - degenerative#Laryngeal hemiplegia|Laryngeal hemiplegia]] due to enlarged retropharyngeal lymph nodes
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**Compression of cranial nerves
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*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]
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===''Streptococcus equi subsp. zooepidemicus''===
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*Causative agent [[Streptococci|''Streptococcus equi subsp. zooepidemicus'']]
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*Can infect the respiratory tract ([[Nasal cavity - inflammatory#Infectious causes of rhinitis|nasal cavity]], [[Paranasal sinuses - inflammatory#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]])
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*URT infection can be indistinguishable clinically from Strangles, but does not cause suppurative lymphadenitis (cf: ''S.equi subsp. equi'')
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===Glanders===
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*Caused by [[Pseudomonas aeruginosa and Burkholderia species|''Burkholderia (Pseudomonas) mallei'']]
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*Exists in eastern Europe and Asia
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*Notifiable in UK
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*Characterised by multiple small submucosal [[Nasal cavity - inflammatory#Infectious causes of rhinitis|nasal nodules]] which liquefy and ulcerate
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**Cores of neutrophils surrounded by a rim of macrophages and [[General Pathology - Chronic Inflammation#Granulation tissue|granulation tissue]]
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*In addition may have similar nodules in [[Lungs - inflammatory#Infectious causes of pneumonia|lungs]], '''lymph nodes''' and '''cutaneous lymphatics''' 
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*Clinical signs: fever and head/ neck lymphadenitis, [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]]
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===''Rhodococcus equi''===
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[[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>]]
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*Causative agent [[Rhodococcus equi|''Rhodococcus (Corynebacterium) equi'']]
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*Important cause of sever, often fatal [[Lungs - inflammatory#Granulomatous pneumonia|granulomatous]] [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] in foals
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*Clinical signs include depression, cough, weight loss, respiratory distress, diarrhoea, arthritis, subcutaneous abscesses
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*Bacterium survives phagocytosis and multiplies
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*Bacterial toxins -> caseous necrosis in lungs -> attracts inflammatory cells -> pyogranulomatous pneumonia
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*Grossly:
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**Multiple firm nodules, usually no encapsulation
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**Partial [[Lungs - ventilation#Atelectasis (Collapse)|atelectasis]]
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*Histologically:
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**Pyogranulomatous lesions
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**Macrophages with ingested microorganisms in the alveoli
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**Necrosis spreading through parenchyma
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==In Cattle==
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===Necrotic laryngitis===
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[[Image:Necrotising laryngitis.jpg|right|thumb|100px|<small><center>Necrotising laryngitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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[[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>]]
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*Synonyms: '''laryngeal diphtheria, calf diphtheria'''
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*Common disease in cattle, and can occur in swine
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*Caused by infection with [[Fusobacterium|''Fusobacterium necrophorum'']] 
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*Lesions may also be found in other parts of the [[Nasopharynx - inflammatory#Infectious causes of pharyngitis|oropharynx]] 
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*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
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*Results in severe acute neutrophilic [[Larynx - inflammatory#Infectious causes of laryngitis|laryngitis]]
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*Extensive accumulation of fibrin and necrotic cellular debris on the ulcerated mucosal surface
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*Lesions appear as dry plaques of fibrinonecrotic exudate and ulceration on the laryngeal mucosa
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*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]]
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*Death may result from toxaemia or asphyxiation
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*Also may occur in pigs
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===''CAR bacillus''===
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*Causative agent: [[Bacillus species|''Cillia-associated respiratory bacillus'']]
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*An unclassified bacteria that can't be grown in culture
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*Colonises ciliated epithelium in '''rodents''' and ruminants
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*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]]
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*Clinical disease in '''rabbits''' and '''rodents'''
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*Subclinical disease in ruminants
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===Pneumonic pasteurellosis===
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*Synonym: '''Shipping fever'''
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*Caused by [[Pasteurella species and Mannheimia haemolytica|''Manheimia haemolytica'' biotype A serotype 1 (90%) and ''Pasteurella multocida'']]
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*In young, growing cattle
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*In clinically normal cattle ''Mann. haemolytica'' serotype 2 is present in low numbers, only in nasal cavity and tonsils
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*Clinical signs: depression, anorexia, rapid shallow respiration, crusty nose with mucopurulent discharge, serous ocular discharge
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*Acute [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchopneumonia]] and may progress to [[Lungs - inflammatory#Lobar pneumonia|lobar pneumonia]] with toxaemia
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*Pathology
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**Lobar, cranioventral exudative pneumonia with fibrin, [[Pleural cavity and membranes - inflammatory|fibrinous pleuritis]], areas of coagulative necrosis
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*Histology
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**Large numbers of bacteria are usually associated with necrotic lesions
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===Tuberculosis===
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[[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>]]
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*Caused by [[Mycobacteria spp.|''Mycobacteruim bovis'' and ''M. tuberculosis'']]
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*Reside primarily within macrophages where they multiply and result in characteristic [[Lungs - inflammatory#Granulomatous pneumonia|granulomatous inflammation]] (macrophages and giant cells, epithelioid cells)
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*Cattle can be infected by inhalation of the organism or through milk
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*'''The primary complex'''
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**Describes the initial focus of infection at the portal of entry (lungs) plus involvement of regional lymph nodes
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**90% of cases exhibit the pulmonary form
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**Grossly:
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***Small tubercles in dorsocaudal subpleural areas which progress to larger confluent areas of caseous necrosis
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***Usually start at bronchio-alveolar junction an progress to the alveoli
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***Caseous lesions, may calcify or be encapsulated
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***Multiple foci may coalesce
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***Ulcers in [[Trachea - inflammatory|trachea]] and [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchi]] due to coughed up bacteria
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***Spreads into [[Pleural cavity and membranes - inflammatory|pleura]]
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**Microscopically:
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***Typical granulomatous inflammation
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***Epitheliod and giant cells at centre of tubercles
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****Macrophages with ingested bacteria, forming epithelioid cells - large vesicular nuclei, abundant pale cytoplasm
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****Giant cells, formed by fusion of macrophages, with multiple nuclei
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***Narrow layer of lymphocytes, mononuclear cells and plasma cells at the periphery of the tubercle
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***With time, peripheral fibroplasia and central necrosis develop
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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
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*This can allow the development of '''miliary tuberculosis''', i.e. numerous small foci of infection in many organs/ tissues
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===Contagious bovine pleuropneumonia (CBPP)===
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[[Image:Contagious bovine pleuropneumonia.jpg|right|thumb|100px|<small><center>Contagious bovine pleuropneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Caused by [[Mycoplasmas|''Mycoplasma mycoides'']], small colony variant
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*Causes a fibrinonecrotic [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] and [[Pleural cavity and membranes - inflammatory|fibrinous pleuritis]]
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*Also affects caudodorsal areas
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*[[Lungs - inflammatory#Bronchopneumonia|Bronchopneumonia]] -> [[Lungs - inflammatory#Lobar pneumonia|lobar pneumonia]]
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*Sequestra are common
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*NB: similarity to pneumonic pasteurellosis but CBPP has more pronounced marbled effect
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*Interstitial septa are markedly widened by fibrinous exudate and the necrotic areas may have a fibrous capsule
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*Large colony variant will cause a similar disease in goats
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===Enzootic pneumonia of calves===
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[[Image:Acute suppurative pneumonia.jpg|right|thumb|100px|<small><center>Acute suppurative pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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[[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>]]
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*Range of infectious agents together with managemental and environmental stress cause damage to the respiratory tract
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*Causes unthriftiness in animals < 6 months old
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*Usually the primary pathogen is a virus, secondary pathogens are bacteria and mycoplasmas
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*Pathogens:
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**[[Mycoplasmas|''Mycoplasmas'']]
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***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
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***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]]
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***It is thought to pick up host antigens in order to prevent recognition by the body defences as foreign
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***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'''
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***More confluent areas can develop with an underlying bronchointestitial pneumonia and resulting atelectasis
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***''M. bovis''
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****Most pathogenic
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****Widespread lymphofollicular accumulations which contain germinal centres develop more slowly
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****These lesions can result in narrowing of the bronchiolar lumina - this is the classical lesion of '''‘cuffing pneumonia’'''
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***''M. dispar''
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***''Ureaplasma'' sp.
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**Viruses
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***[[Respiratory Viral Infections - Pathology#Respiratory syncytial virus|Bovine respiratory syncytial virus (BRSV)]] - can be primary, causes suppression of pulmonary immune response
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***[[Respiratory Viral Infections - Pathology#Parainfluenza- 3|Parainfluenza- 3 (PI3)]] - can be primary, causes suppression of pulmonary immune response
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***[[Flaviviridae|Bovine viral diarrhoea virus (BVDV)]] - suppression of pulmonary immune response
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***[[Adenoviridae|Adenoviruses]]
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***[[Coronaviridae|Calf coronavirus]]
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***[[Respiratory Viral Infections - Pathology#Infectious bovine rhinotracheitis (IBR)|Bovine herpes viruses]]
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**Bacteria
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***[[Pasteurella species and Mannheimia haemolytica|''Manheimia (Pasteurella) haemolytica'' serotype A1]]
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***[[Pasteurella species and Mannheimia haemolytica|''Pasteurella multocida'']]
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***[[Arcanobacter pyogenes|''Arcanobacter pyogenes'']]
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***[[Haemophilus species|''Haemophilus sommus'']]
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*All transmitted by aerosol and direct contact
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*Gross pathology:
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**Consolidation of the cranioventral areas which increases in volume with duration
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**On cut surface, exudate in the main airway of affected lobules with thickening of the surrounding connective tissue
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*Micro pathology:
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**Substantial lymphoid tissue around the airways
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**Even to proper follicle formation, some of which may be large enough to compress the lumen
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**Mixed cell exudate in the airway lumen
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**Partial alveolar collapse distal to the compression
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**Alveolar exudate contains a mixture of inflammatory cells
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**Slight thickening of the alveolar walls with lymphocytes
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===Acute exudative pneumonia===
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*[[Lungs - inflammatory#Infectious causes of pneumonia|Pneumonia]] in very young calves
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*[[Arcanobacter pyogenes|''Arcanobacter pyogenes'']] is most frequently isolated
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*Cranio-ventral distribution
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==In Sheep==
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===Laryngeal chondritis===
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[[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>]]
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*Caused by [[Fusobacterium|''Fusobacterium necrophorum'']] 
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*[[Larynx - inflammatory#Infectious causes of laryngitis|Infection of laryngeal cartilages]]
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*Can be seen in short-necked breed, e.g. Texels, East Friesians and Southdowns
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*Leads to extreme respiratory distress
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*Laryngeal mucosa is necrotic and ulcerated
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*Associated with [[Larynx - degenerative#Laryngeal oedema|laryngeal oedema]]
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*Also may occur in young [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]] and calves
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===''CAR bacillus''===
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*As [[Bacterial infections#CAR bacillus|in cattle]]
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===Enzootic pneumonia of lambs===
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*Caused by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella (Manheimia) haemolytica'']], possibly together with [[Mycoplasmas|''Mycoplasma ovipneumoniae'']]
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*Mainly in late spring/early summer after environmental stress i.e. handling or moving
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*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 and membranes - inflammatory|pleuritis]]
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*Or tending towards chronicity with abscessation and fibrous pleural adhesions
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*A septicaemic form (mortality 5%) is reported to follow the stress of movement to new pasture in the autumn in weaned lambs.
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*Foci of necrosis containing many bacteria are seen at the site of initial invasion in the pharynx and in the '''[[Liver - Anatomy & Physiology|liver]]'''
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*Meningitis in young lambs and mastitis in ewes are other expressions
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===Melioidosis (Pseudoglanders)===
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*Caused by [[Pseudomonas aeruginosa and Burkholderia species|''Pseudomonas (Malleomyces) pseudomallei'']], Closely related to [[Bacterial infections#Glanders|''P. mallei'']] in [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]]
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*Causes disease in sheep, goats and pigs, occasionally other species
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*Starts as a pyemia and localises in varius tissues, including the lung as abscessation
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**Encapsulated abscesses contain yellow, caseous or creamy pus
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*[[Lungs - inflammatory#Infectious causes of pneumonia|Pneumonia]] and arthritis are the most common presentation
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==In Pigs==
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===Atrophic Rhinitis===
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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
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**[[Bordetella bronchiseptica and Bordetella avium|''Bordetella bronchiseptica'']]
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***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 [[Bacterial infections#In Cattle|in cattle]]
 +
*Caused by infection with [[Fusobacterium|''Fusobacterium necrophorum'']]
 +
 +
===Enzootic pneumonia of pigs===
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[[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 and membranes - inflammatory|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 [[Bacterial infections#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 and membranes - inflammatory|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
 +
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===Contagious porcine pleuropneumonia===
 +
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*Caused by [[Haemophilus species|''Haemophilus (Actinobacillus) pleuropneumonia'']]
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*Seen mainly between 6wks-6mths of age but will affect any age
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*Highly pathogenic strains are capable of initiating disease on their own with high mortality in young pigs
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*A fibrinonecrotic [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] with [[Pleural cavity and membranes - inflammatory|pleurisy]]
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*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
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===Glasser's disease===
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*Caused by [[Haemophilus species|''Haemophilus parasuis'']]
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*May cause suppurative [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|broncho]][[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] and [[Pleural cavity and membranes - inflammatory|pleuritis]] (as part of polyserositis)
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*Stress of mixing, weaning and adverse environmental conditions are predisposing to the disease
 +
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===Streptococcal pneumonia===
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*Caused by [[Streptococci|''Streptococcus suis'' type II]]
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*Zoonotic
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*Carried in nasal cavity and lymph nodes of healthy pigs
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*Some serotypes may cause [[Lungs - inflammatory#Embolic pneumonia|embolic pneumonia]], others suppurative or fibrinous [[Lungs - inflammatory#Bronchopneumonia|bronchopneumonia]], often in combination with other bacteria
 +
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===Tuberculosis in pigs===
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*Pigs are susceptible to the [[Mycobacteria spp.|''Mycobacterium'' spp.]] causing tuberculosis [[Bacterial infections#Tuberculosis|in cattle]]
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*Rarely extends to lungs after haematogenous spread from ingested bacteria causing tubercles with various degrees of calcification, encapsulation and caseation
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==In Rabbits==
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===Snuffles===
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*Caused by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella multocida'']], less commonly and/or [[Bordetella bronchiseptica and Bordetella avium|''B.bronchoseptica'']]
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*Clinical signs (nasal discharge, sneezing) result from an acute to chronic [[Nasal cavity - inflammatory|rhinitis]]
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===''CAR bacillus''===
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*As [[Bacterial infections#CAR bacillus|in cattle]]
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