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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|monocytes]]
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| − | **Impairing the phagocytic ability of alveolar macrophages
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| − | ==In Dogs==
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| − | [[Canine Distemper Virus]]
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| − | [[Canine Parainfluenza - 2]]
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| − | [[Infectious Canine Tracheitis|Infectious canine tracheitis]]
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| − | [[Canine Adenovirus 1]]
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| − | [[Canine Adenovirus 2]]
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| − | [[Canine Herpesvirus 1]]
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| − | [[Canine Respiratory Coronavirus]]
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| − | ==In Cats==
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| − | ===[[Feline Herpesvirus 1|Feline viral rhinotracheitis]]===
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| − | ===[[Feline Calicivirus]]===
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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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| − | ===[[Equine Influenza|Equine influenza]]===
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| − | ===[[Equine Rhinopneumonitis]] ===
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| − | ===[[Equine Viral Arteritis]]===
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| − | ===[[Equine Adenovirus]]===
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| − | ===[[African Horse Sickness]]===
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| − | ===[[Hendra Virus]]===
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| − | ==In Cattle==
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| − | ===[[Infectious Bovine Rhinotracheitis|Infectious bovine rhinotracheitis (IBR)]]===
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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 [[:Category:Pasteurella and Mannheimia species|''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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| − | ===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|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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| − | ==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]] 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|Swine influenza]]===
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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]]===
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