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| − | {{review}}
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| − | {{toplink
| + | #REDIRECT[[:Category:Respiratory Viral Infections]] |
| − | |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>
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| − | ==In general==
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| − | | |
| − | *Some viruses are thought to induce modifications of the pulmonary defences by:
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| − | **Damaging the upper respiratory tract, thereby facilitating bacterial attachment and colonisation, with reduced [[Respiratory System General Introduction - Pathology#Mucociliary escalator|mucociliary clearance]]
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| − | **Decreasing surfactant levels by destroying Type 2 pneu[[Monocytes - WikiBlood]]
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| − | **Impairing the phagocytic ability of alveolar macrophages
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| − | | |
| − | | |
| − | ==In Dogs==
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| − | | |
| − | ===Canine distemper===
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| − | | |
| − | *Caused by a [[Paramyxoviridae#Canine Distemper Virus (CDV)|morbillivirus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]]
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| − | *Although many organs can be affected by CDV, a relatively constant feature is the respiratory signs which occur in varying severity
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| − | *A syndrome of catharral oculonasal discharge, [[Nasopharynx Inflammatory - Pathology#Infectious causes of pharyngitis|pharyngitis]] and [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]] is relatively common in the initial stages
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| − | *Since one of the primary sites of action of this virus is lymphoid tissue, the resultant immunosuppression -> predisposition to secondary bacterial infection
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| − | *May cause [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] where [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|inclusions]] are found within alveolar macrophages
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| − | *Gross pathology:
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| − | **Oedematous lungs, diffuse interstitial pneumonia
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| − | *Micro pathology:
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| − | **Necrosis of pneumocytes, necrotising bronchiolitis, alveolar oedema, thickening of alveolar walls and type II pneumocyte hyperplasia
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| − | | |
| − | | |
| − | ===Parainfluenza- 2===
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| − | | |
| − | *Caused by an [[Paramyxoviridae|parainfluenza- 2 virus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]], [[Trachea Inflammatory - Pathology|tracheo]][[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]]
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| − | | |
| − | | |
| − | ===Infectious canine tracheitis===
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| − | *Synonyms: '''Kennel cough''', '''Infectious tracheobronchitis'''
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| − | *[[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|tracheitis]], [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]]
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| − | *Multiple agents implicated:
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| − | **[[Adenoviridae|Canine adenovirus-2]]
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| − | **[[Paramyxoviridae|Canine parainfluenza-2 virus]]
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| − | **[[Paramyxoviridae#Canine Distemper Virus (CDV)|Canine distemper virus]]
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| − | **[[Bordetella bronchiseptica and Bordetella avium|''Bordetella bronchoseptica'']]
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| − | *Symptoms are of a persistent, non-productive cough
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| − | *Persistent tracheobronchial inflammation
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| − | *The outcomes is generally recovery (may persist >3 weeks), but extension to [[Bronchi and Bronchioles Inflammatory - Pathology|chronic bronchitis]] or cranioventral [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|bronchopneumonia]] may occur
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| − | *In severe cases can extend to serous/mucopurulent [[Nasal Cavity Inflammatory - Pathology#Rhinitis|rhinitis]]
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| − | *Lesions are neither specific nor always significant (catarrhal / mucopurulent tracheobronchitis)
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| − | *Enlarged tonsils and retropharyngeal lymph nodes
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| − | | |
| − | ===Canine adenovirus===
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| − | [[Image:Adenovirus pneumonia.jpg|right|thumb|100px|<small><center>Adenovirus pneumonia (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | | |
| − | *[[Adenoviridae|Adenoviridae]]
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| − | *Usually mild [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]], necrosis of bronchiolar and alveolar epithelium, oedema, type II pneumocyte hyperplasia
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| − | *May cause necrotising [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]] in immune-deficient dogs ([[Paramyxoviridae#Canine Distemper Virus (CDV)|distemper]])
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| − | *Can be associated with [[Respiratory Viral Infections - Pathology#Infectious canine tracheitis|kennel cough]] described above
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| − | | |
| − | ===Canine herpes virus===
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| − | | |
| − | *Caused by [[Herpesviridae|canine herpes virus 1]]
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| − | *Part of '''fading puppy syndrome'''
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| − | *Presents with necrotising [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhino]][[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|tracheitis]] and secondary [[Lungs Inflammatory - Pathology#Bronchopneumonia|bronchopneumonia]] in older dogs
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| − | *Seems to be common subclinically
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| − | | |
| − | | |
| − | ===Canine respiratory coronavirus===
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| − | | |
| − | *(CRCV)
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| − | *Shown to be involved in an outbreak of disease in large kennels with rapidly changing population and high incidence of respiratory disease
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| − | *Erles, K., Toomey, C. ''et al.''(2003) "Detection of a group 2 coronavirus in dogs with canine infectious respiratory disease." Virology '''310'''(2):216-223
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| − | ==In Cats==
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| − | | |
| − | ===Feline viral rhinotracheitis===
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| − | | |
| − | *Caused by a [[Herpesviridae|herpesvirus]]
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| − | *Tends to be more [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]] than [[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|tracheitis]], may extend to [[Paranasal Sinuses Inflammatory - Pathology#Infectious causes of sinusitis|sinusitis]]
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| − | *Feline herpesvirus -1
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| − | **One of the causes of Feline viral rhinotracheitis
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| − | ***Viruses and bacteria are involved in the complex. The most frequent aetiologic agent is [[Herpesviridae|FHV-1]], and less frequently [[Caliciviridae|feline calicivirus]] and/or [[Chlamydia and Chlamydophila species|''Chlamydophila psittaci'']] (NB: previously called ''Chlamydia psittaci'' var felis)
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| − | *All three agents infect URT respiratory epithelium, although FHV-1 has the highest affinity for this epithelium
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| − | *Feline calicivirus more frequently infects the oral mucosa -> ulcerative stomatitis
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| − | *''C.psittaci'' more frequently infects the conjunctival epithelium -> chronic conjunctivitis
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| − | *Infection of the respiratory epithelium by FHV-1 results in a typical neutrophilic rhinitis with intraepitheial intranuclear eosinophilic [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|inclusion bodies]]
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| − | *Uncomplicated cases resolve in 2-3 weeks
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| − | *FHV-1 remains latent in the trigeminal ganglion, and can reactivate at times of stress
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| − | *Can infect the cornea -> ulcerative keratitis
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| − | *Mortality may be high in young kittens, debilitated and immune-suppressed animals, usually associated with secondary bacterial infection.
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| − | | |
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| − | ===Feline calicivirus===
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| − | | |
| − | *Causative agent: [[Caliciviridae|feline calicivirus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]],
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| − | *Suggested in the presence of ulceration of the dorsal and lateral edges of the [[Oral Cavity - Tongue - Anatomy & Physiology|tongue]], hard palate and external nares
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| − | *Lesions present may include [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] with necrotising [[Bronchi and Bronchioles - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]]
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| − | *Also see Feline viral rhinotracheitis above
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| − | | |
| − | ==In Horses==
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| − | [[Image:Equine respiratory viruses concept map.jpg|right|thumb|100px|<small><center>Equine respiratory viruses Concept Map (Courtesy of B. Stanikova)</center></small>]]
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| − | | |
| − | ===Equine rhinovirus===
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| − | *Causative agent: [[Picornaviridae|equine rhinovirus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology|Rhinitis]]
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| − | *Most common in young horses
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| − | *May cause acute upper respiratory disease
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| − | | |
| − | | |
| − | ===Equine influenza===
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| − | *Causative agent: [[Orthomyxoviridae|equine influenza virus (Orthomyxovirus)]]
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| − | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]],
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| − | *Pathogenesis:
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| − | **Inhalation -> replication in epithelial cells of upper and lower airways (attaches via haemaglutinin spike and gains entry into cell) -> neuramidase alters efficiency of [[Respiratory System General Introduction - Pathology#Mucociliary escalator|mucociliary apparatus]]
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| − | *Sloughing of the affected area
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| − | *Severity of signs will depend on dose of virus
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| − | *Acute [[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|tracheo]][[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]] with coughing, and fever
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| − | *May be accompanied by secondary bacterial infections
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| − | *No viraemia
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| − | *In severe cases may cause [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
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| − | *Secondary invaders are usually [[Streptococci|''Streptococci'']]
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| − | | |
| − | | |
| − | ===Equine rhinopneumonitis ===
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| − | *Causative agent: [[Herpesviridae|equine herpesvirus type 1 and type 4]]
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| − | *Primary viral lesions in [[Nasal Cavity Inflammatory - Pathology|nasal mucosa]] and [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|lungs]]
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| − | *Mild, transient [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
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| − | *Latent infection acting as a reservoir
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| − | *Sites of latency: bronchial lymph nodes and trigeminal ganglia
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| − | *Replicates in upper respiratory tract epithelium
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| − | *Disseminated to lower respiratory tract
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| − | *Transported to other organs in T-lymphocytes - viraemia up to 3 weeks
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| − | *Vasculitis, abortion
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| − | *May be accompanied by secondary bacterial infection
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| − | | |
| − | | |
| − | ===Equine viral arteritis (EVA)===
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| − | *Causative agent: [[Arteriviridae|equine arterivirus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], peripheral oedema, [[Bronchi and Bronchioles Inflammatory - Pathology|bronchitis/bronchiolitis]], conjunctivitis, periorbital oedema
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| − | *Replicates in macrophages and endothelial cells
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| − | *Disseminates via the circulatory system causing necrotising arteritis
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| − | *[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]
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| − | *Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
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| − | *Stallion are a reservoir of infection as they are chronic shedders
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| − | | |
| − | | |
| − | ===Equine adenovirus===
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| − | [[Image:Adenovirus in equine lung.jpg|right|thumb|100px|<small><center>Adenovirus in equine lung (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | | |
| − | *[[Adenoviridae|Adenoviridae]]
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| − | *May cause necrotising [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]] in immune-deficient foals (Arabian foals)
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| − | *Grossly:
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| − | **[[Lungs Ventilation - Pathology#Atelectasis (Collapse)|Atelectasis]] and consolidation of lobules in cranioventral region
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| − | **Mucopurulent exudate in airways
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| − | *Histologically:
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| − | **Severe bronchiolitis, necrotising -> proliferative
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| − | **Bronchiolar obstruction by sloughed debri and [[Neutrophils - WikiBlood|neutrophils]] -> alveolar atelectasis
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| − | *May lead to secondary bacterial infections
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| − | | |
| − | | |
| − | ===African horse sickness===
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| − | [[Image:Lung oedema in African horse sickness.jpg|right|thumb|100px|<small><center>Lung oedema in African horse sickness (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | | |
| − | *Caused by [[Reoviridae|orbivirus]], family reoviridae
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| − | *Respiratory distress or cardiovascular failure
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| − | *Rapid death due to massive [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]]
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| − | *[[Pleural Cavity & Membranes Degenerative - Pathology#Hydrothorax|Hydrothorax]] may also develop
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| − | *Large amounts of froth present in airways
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| − | | |
| − | ===Hendra virus===
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| − | | |
| − | *Causative agent [[Paramyxoviridae|equine morbillivirus]]
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| − | *Oedematous lungs with distention of [[Pleural Cavity & Membranes Inflammatory - Pathology|pleura]]
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| − | *Micro: diffuse [[Lungs Circulatory - Pathology#Pulmonary oedema|alveolar oedema]], syncytial cells
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| − | ==In Cattle==
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| − | ===Infectious bovine rhinotracheitis (IBR)===
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| − | [[Image:IBR nasal cavity.jpg|right|thumb|100px|<small><center>IBR in nasal cavity (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | [[Image:IBR trachea.jpg|right|thumb|100px|<small><center>IBR in trachea (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | | |
| − | *Causative agent is [[Herpesviridae|'''bovine herpesvirus, type 1''']]
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| − | *URT infection with serous nasal discharge, increases respiratory rate, coughing and moderate fever,from nasal mucosa down to bronchioles
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| − | *[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], [[Nasopharynx Inflammatory - Pathology#Infectious causes of pharyngitis|pharyngitis]], [[Larynx Inflammatory - Pathology|laryngitis]], [[Trachea Inflammatory - Pathology|tracheitis]], [[Bronchi and Bronchioles Inflammatory - Pathology|bronchiolitis]]
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| − | *Morbidity is high, mortality is low
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| − | *Highly infectious URT disease of cattle
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| − | *Spread by movement of animals, aerosol transmission - requires close contact between animals
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| − | *Early stages (only first few days) may show [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intracellular inclusions]] in the respiratory mucosal epithelial cells
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| − | *Leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent
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| − | *With secondary bacterial infection (eg: [[Pasteurella species and Mannheimia haemolytica|Pasturella spp.]], [[Mycoplasmas|Mycoplasma spp.]], [[Fusobacterium|Fusobacterium necrophorum]]) can lead to fibrinous to necrotizing inflammation; mucosal sloughing, ulceration... pyrexia, dyspnoea ... [[Lungs Inflammatory - Pathology#Aspiration pneumonia|inhalation pneumonia]]... death
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| − | *Underlying hyperaemic inflammatory response
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| − | *Can become latent following primary infection
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| − | *Clinical signs:nasal discharge, sneezing, coughing, lacrimation, and increased respiratory rate
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| − | *Clinical disease most severe in young calves - can develop mucosal ulcerative lesions in the [[Oesophagus - Pathology#Erosive & Ulcerative Pathology|oesophagus]] and forestomachs and viraemia with multiorgan infection
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| − | *Cause of abortion >5 months of gestation
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| − | *May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]
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| − | ===Parainfluenza- 3===
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| − | | |
| − | *Causative agent: [[Paramyxoviridae#Bovine Parainfluenza - 3 (PI-3)|parainfluenza- 3 virus]] (PI3)
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| − | *On its own causes [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]]
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| − | *Often part of multi-aetiology disease complex (e.g. [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]), often followed by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella sp.'']] obscuring viral origin
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| − | *Replicates in airway epithelial cells and results in an initial [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis -> bronchiolitis]] -> extension into [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|alveoli]], causing [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
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| − | *Early stages may show [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intracytoplasmic inclusions]]
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| − | *The resulting exudate is predominantly neutrophilic
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| − | *Positive confirmation lies in a Fluorescent Antibody Test (FAT) to the specific virus on frozen sections of tissue
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| − | ===Bovine adenovirus===
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| − | | |
| − | *Causative agent: [[Adenoviridae|bovine adenovirus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]]
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| − | *May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]
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| − | ===Respiratory syncytial virus===
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| − | | |
| − | *Causative agent [[Paramyxoviridae|Respiratory syncytial virus (RSV)]], synonym: bovine RSV (BRSV)
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| − | *Outbreaks of RSV associated disease usually occur associated with winter housing
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| − | *Gross pathology in severe cases
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| − | **Cranioventral [[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]] and consolidation
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| − | **[[Lungs Ventilation - Pathology#Emphysema|Interstitial emphysema]]
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| − | ***More prominent in the caudal lung lobes
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| − | ***Results from bronchoconstriction which results in airway obstruction - this constriction is thought to arise from [[Mast Cells - WikiBlood|mast cell]] degranulation and histamine release
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| − | *Histologically
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| − | **[[Bronchi and Bronchioles Inflammatory - Pathology#Acute bronchitis/bronchiolitis|Acute bronchiolitis]], characteristic of the bronchiolar response is the formation of syncytial giant cells (formed by proliferating bronchiolar epithelial cells which may contain [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intracytoplasmic inclusion bodies]]), alveolar epithelium sometimes affected
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| − | **Obstruction of bronchioles by exudate - these may later become obliterated by the fibrous tissue of organisation
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| − | *May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]
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| − | | |
| − | ===Bovine rhinovirus===
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| − | | |
| − | *Causative agent: [[Picornaviridae|bovine rhinovirus]]
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| − | *May cause mild respiratory disease
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| − | | |
| − | | |
| − | ==In Sheep==
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| − | | |
| − | ===Maedi Visna===
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| − | | |
| − | *Caused by a [[Retroviridae|retrovirus]]
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| − | *The respiratory from of the disease caused by maedi-visna virus (Maedi) is also called '''lymphoid interstitial pneumonia'''
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| − | *Transmitted by close contact and via milk
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| − | *The pulmonary lesions develop very slowly hence this disease is uncommon in sheep < 2 years old
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| − | *Increased respiratory rate upon exertion, loss of weight
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| − | *Remains in [[Monocytes - WikiBlood]] and macrophages
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| − | *Gross findings
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| − | **Severe [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]]
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| − | **Lungs fail to collapse properly on opening the chest and can weigh more than twice the normal weight
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| − | **Impressions of the ribs remain on the visceral pleura
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| − | **Lungs are a mottled grey/ tan colour - the lesions can vary from irregular grey speckling to homogeneous grey consolidation
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| − | **Rubbery in consistence
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| − | **Diaphragmatic lobes most affected
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| − | **Associated bronchial and mediastinal lymph nodes are often enlarged
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| − | *Histologically
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| − | **Major features are extensive lymphoid proliferation around perivascular, peribronchial and peribronchiolar sheaths associated with pulmonary lymphatics
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| − | **Many of these areas contain germinal centres and smooth muscle hyperplasia (in walls of terminal bronchioles and alveoli)
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| − | | |
| − | | |
| − | ===Parainfluenza -3===
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| − | | |
| − | *As in [[Respiratory Viral Infections - Pathology#Parainfluenza- 3|cattle]]
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| − | | |
| − | | |
| − | ===Pulmonary adenomatosis===
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| − | | |
| − | *See [[Lungs Hyperplastic and Neoplastic - Pathology#Sheep pulmonary adenomatosis (SPA/ Jaagsiekte)|neoplasia]]
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| − | | |
| − | | |
| − | ==In Goats==
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| − | | |
| − | ===Caprine Arthritis-Encephalitis (CAE)===
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| − | | |
| − | *Caused by [[Retroviridae|retrovirus (lentivirus)]] similar to [[Respiratory Viral Infections - Pathology#Maedi Visna|Maedi Visna]] in sheep described above
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| − | *Two forms:
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| − | **Non-suppurative leukoencephalomyelitis in young goats and kids
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| − | **Chronic, non-suppurative arthritis-synovitis in adult goats
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| − | *Also causes [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] which tends to be obscured by other clinical signs
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| − | *Gross pathology:
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| − | **Mainly caudal lobes
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| − | **Lungs are firm, grey-pink with grey-white focal lesions on cut surface
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| − | *Micro pathology:
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| − | **Thickened alveolar wall
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| − | **Lymphocyte infiltration and type II pneumocyte hyperplasia
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| − | *Can be confused with or coexisting with [[Lungs Inflammatory - Pathology#Verminous pneumonia|Parasitic pneumonia]]
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| − | | |
| − | | |
| − | ==In Pigs==
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| − | | |
| − | ===Inclusion body rhinitis===
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| − | [[Image:Inclusion body rhinitis.jpg|right|thumb|100px|<small><center>Inclusion body rhinitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | | |
| − | *[[Herpesviridae|'''Herpesviridae, porcine cytomegalovirus''']]
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| − | *Disease of suckling piglets 1-5 wks of age
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| − | *Clinical signs: those associated with acute/subacute [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]] (ie: serous nasal discharge, progressing to catarrhal or purulent discharge with time and secondary bacterial infections; sneezing; pyrexia), fever in young piglets (3-8wks old)
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| − | *May progress to [[Paranasal Sinuses Inflammatory - Pathology#Sinusitis|sinusitis]], otitis media or [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
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| − | *Morbitity high, mortality low
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| − | *Gross pathology - catarrhal discharge becoming purulent (secondary infection)
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| − | *Histology:
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| − | **Large basophilic [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intranuclear inclusion bodies]] in the surface and subepithelium of nasal and sinus glandular epithelium with lymphocytic infiltration of the mucosa
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| − | **Bursting of nucleus with cell necrosis and sloughing of necrotic epithelium
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| − | *Can develop viraemic stage, with inclusions and focal necrotising lesions in other organs eg: renal tubular epithelium
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| − | **Usually younger piglets, can die during this phase
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| − | *Usually resolves if uncomplicated but rhinitis may persist if secondary infection is present
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| − | *May persist in pulmonary macrophages
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| − | | |
| − | | |
| − | ===Swine influenza===
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| − | | |
| − | *Caused by [[Orthomyxoviridae|Swine influenza virus]]
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| − | *[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], may progress to [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
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| − | *Clinical signs: pyrexia, lethargy, skin erythema, anorexia, severe cough and sneezing, dyspnoea, conjunctivitis, pregnant sows may abort
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| − | *Grossly:
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| − | **[[Trachea Inflammatory - Pathology|Tracheo]][[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]], airway obstruction -> [[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]]
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| − | **[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleura]] normal or covered with serous or serofibrinous exudate
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| − | **[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleural cavity]] filled with excess fluid
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| − | **Lung lesions
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| − | ***Clear demarcation of lesions in cranial and middle lobes
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| − | ***[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]
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| − | *Histologically:
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| − | **Acute inflammation of mucosa of trachea and bronchi
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| − | *Zoonotic
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| − | *Circumstantial evidence of mutation from human strain
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| − | *Migrating [[Respiratory Parasitic Infections - Pathology#Ascaris suum|ascarids]] thought to precipitate the disease, reservoir of infection in earthworms containing infected lungworm larvae
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| − | ===Porcine reproductive and respiratory syndrome===
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| − | | |
| − | *The syndrome is caused by a small enveloped RNA virus which belongs to the new [[Arteriviridae|Arteriviridae]] group
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| − | *Replicates in and destroys macrophages and endothelial cells causing vasculitis -> viraemia -> virus shedding (nasal secretions, faeces)
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| − | *Clinical signs: respiratory and reproductive failure, weaned pigs, tachypnoea, eyelid oedema, conjunctivitis
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| − | *Moderate to severe interstitial [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] in the cranial lobe
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| − | *Superimposed bacterial infections are common
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| − | *Infectious disease in swine that emerged 10 years ago
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| − | *Today, PRRS is endemic in many if not all the pig-producing countries
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| − | ===Postweaning multisystemic wasting syndrome (PMWS)===
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| − | | |
| − | *Caused by a [[Circoviridae|porcine circovirus]] alone or in combination with [[Parvoviridae|porcine parvovirus]]
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| − | *May cause mild [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]], failure of lungs to collpse on opening the thoracic cavity
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| − | *Microscopically: thickening of alveolar wall due to type 2 pneumocyte hyperplasia
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| − | ===Porcine respiratory coronavirus (PRCV)===
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| − | | |
| − | *Caused by a [[Coronaviridae|coronavirus]]
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| − | *Usually mild [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] unless complicated by other agents
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| − | *Virus replicates in epithelial lining of airways
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