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Respiratory Viral Infections (view source)
Revision as of 21:30, 6 August 2008
, 21:30, 6 August 2008no edit summary
*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
*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
*Since one of the primary sites of action of this virus is lymphoid tissue, the resultant immunosuppression -> predisposition to secondary bacterial infection
*Since one of the primary sites of action of this virus is lymphoid tissue, the resultant immunosuppression -> predisposition to secondary bacterial infection
*May cause [[Lungs - inflammatory#Interstitial pneumonia|interstitial pneumonia]] where [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|inclusions]] are found within alveolar macrophages
*May cause [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] where [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|inclusions]] are found within alveolar macrophages
*Gross pathology:
*Gross pathology:
**Oedematous lungs, diffuse interstitial pneumonia
**Oedematous lungs, diffuse interstitial pneumonia
*Symptoms are of a persistent, non-productive cough
*Symptoms are of a persistent, non-productive cough
*Persistent tracheobronchial inflammation
*Persistent tracheobronchial inflammation
*The outcomes is generally recovery (may persist >3 weeks), but extension to [[Bronchi and Bronchioles Inflammatory - Pathology|chronic bronchitis]] or cranioventral [[Lungs - inflammatory#Infectious causes of pneumonia|bronchopneumonia]] may occur
*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
*In severe cases can extend to serous/mucopurulent [[Nasal Cavity Inflammatory - Pathology#Rhinitis|rhinitis]]
*In severe cases can extend to serous/mucopurulent [[Nasal Cavity Inflammatory - Pathology#Rhinitis|rhinitis]]
*Lesions are neither specific nor always significant (catarrhal / mucopurulent tracheobronchitis)
*Lesions are neither specific nor always significant (catarrhal / mucopurulent tracheobronchitis)
*[[Adenoviridae|Adenoviridae]]
*[[Adenoviridae|Adenoviridae]]
*Usually mild [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]], necrosis of bronchiolar and alveolar epithelium, oedema, type II pneumocyte hyperplasia
*Usually mild [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]], necrosis of bronchiolar and alveolar epithelium, oedema, type II pneumocyte hyperplasia
*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]])
*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]])
*Can be associated with [[Respiratory Viral Infections - Pathology#Infectious canine tracheitis|kennel cough]] described above
*Can be associated with [[Respiratory Viral Infections - Pathology#Infectious canine tracheitis|kennel cough]] described above
*Caused by [[Herpesviridae|canine herpes virus 1]]
*Caused by [[Herpesviridae|canine herpes virus 1]]
*Part of '''fading puppy syndrome'''
*Part of '''fading puppy syndrome'''
*Presents with necrotising [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhino]][[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|tracheitis]] and secondary [[Lungs - inflammatory#Bronchopneumonia|bronchopneumonia]] in older dogs
*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
*Seems to be common subclinically
*Seems to be common subclinically
*[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]],
*[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]],
*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
*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
*Lesions present may include [[Lungs - inflammatory#Interstitial pneumonia|interstitial pneumonia]] with necrotising [[Bronchi and Bronchioles - Patholgoy#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]]
*Lesions present may include [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] with necrotising [[Bronchi and Bronchioles - Patholgoy#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]]
*Also see Feline viral rhinotracheitis above
*Also see Feline viral rhinotracheitis above
*May be accompanied by secondary bacterial infections
*May be accompanied by secondary bacterial infections
*No viraemia
*No viraemia
*In severe cases may cause [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
*In severe cases may cause [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
*Secondary invaders are usually [[Streptococci|''Streptococci'']]
*Secondary invaders are usually [[Streptococci|''Streptococci'']]
===Equine rhinopneumonitis ===
===Equine rhinopneumonitis ===
*Causative agent: [[Herpesviridae|equine herpesvirus type 1 and type 4]]
*Causative agent: [[Herpesviridae|equine herpesvirus type 1 and type 4]]
*Primary viral lesions in [[Nasal Cavity Inflammatory - Pathology|nasal mucosa]] and [[Lungs - inflammatory#Infectious causes of pneumonia|lungs]]
*Primary viral lesions in [[Nasal Cavity Inflammatory - Pathology|nasal mucosa]] and [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|lungs]]
*Mild, transient [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
*Mild, transient [[Lungs Inflammatory - Pathology#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
*Latent infection acting as a reservoir
*Latent infection acting as a reservoir
*Sites of latency: bronchial lymph nodes and trigeminal ganglia
*Sites of latency: bronchial lymph nodes and trigeminal ganglia
*Replicates in macrophages and endothelial cells
*Replicates in macrophages and endothelial cells
*Disseminates via the circulatory system causing necrotising arteritis
*Disseminates via the circulatory system causing necrotising arteritis
*[[Lungs - inflammatory#Interstitial pneumonia|Interstitial pneumonia]]
*[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]
*Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
*Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
*Stallion are a reservoir of infection as they are chronic shedders
*Stallion are a reservoir of infection as they are chronic shedders
*Early stages (only first few days) may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracellular inclusions]] in the respiratory mucosal epithelial cells
*Early stages (only first few days) may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracellular inclusions]] in the respiratory mucosal epithelial cells
*Leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent
*Leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent
*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#Aspiration pneumonia|inhalation pneumonia]]... death
*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
*Underlying hyperaemic inflammatory response
*Underlying hyperaemic inflammatory response
*Can become latent following primary infection
*Can become latent following primary infection
*On its own causes [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]]
*On its own causes [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]]
*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
*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
*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#Infectious causes of pneumonia|alveoli]], causing [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]
*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]]
*Early stages may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusions]]
*Early stages may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusions]]
*The resulting exudate is predominantly neutrophilic
*The resulting exudate is predominantly neutrophilic
*Remains in monocytes and macrophages
*Remains in monocytes and macrophages
*Gross findings
*Gross findings
**Severe [[Lungs - inflammatory#Interstitial pneumonia|interstitial pneumonia]]
**Severe [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]]
**Lungs fail to collapse properly on opening the chest and can weigh more than twice the normal weight
**Lungs fail to collapse properly on opening the chest and can weigh more than twice the normal weight
**Impressions of the ribs remain on the visceral pleura
**Impressions of the ribs remain on the visceral pleura
**Non-suppurative leukoencephalomyelitis in young goats and kids
**Non-suppurative leukoencephalomyelitis in young goats and kids
**Chronic, non-suppurative arthritis-synovitis in adult goats
**Chronic, non-suppurative arthritis-synovitis in adult goats
*Also causes [[Lungs - inflammatory#Interstitial pneumonia|interstitial pneumonia]] which tends to be obscured by other clinical signs
*Also causes [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]] which tends to be obscured by other clinical signs
*Gross pathology:
*Gross pathology:
**Mainly caudal lobes
**Mainly caudal lobes
**Thickened alveolar wall
**Thickened alveolar wall
**Lymphocyte infiltration and type II pneumocyte hyperplasia
**Lymphocyte infiltration and type II pneumocyte hyperplasia
*Can be confused with or coexisting with [[Lungs - inflammatory#Verminous pneumonia|Parasitic pneumonia]]
*Can be confused with or coexisting with [[Lungs Inflammatory - Pathology#Verminous pneumonia|Parasitic pneumonia]]
*Disease of suckling piglets 1-5 wks of age
*Disease of suckling piglets 1-5 wks of age
*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)
*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)
*May progress to [[Paranasal Sinuses Inflammatory - Pathology#Sinusitis|sinusitis]], otitis media or [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]]
*May progress to [[Paranasal Sinuses Inflammatory - Pathology#Sinusitis|sinusitis]], otitis media or [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
*Morbitity high, mortality low
*Morbitity high, mortality low
*Gross pathology - catarrhal discharge becoming purulent (secondary infection)
*Gross pathology - catarrhal discharge becoming purulent (secondary infection)
*Caused by [[Orthomyxoviridae|Swine influenza virus]]
*Caused by [[Orthomyxoviridae|Swine influenza virus]]
*[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], may progress to [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]]
*[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], may progress to [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]
*Clinical signs: pyrexia, lethargy, skin erythema, anorexia, severe cough and sneezing, dyspnoea, conjunctivitis, pregnant sows may abort
*Clinical signs: pyrexia, lethargy, skin erythema, anorexia, severe cough and sneezing, dyspnoea, conjunctivitis, pregnant sows may abort
*Grossly:
*Grossly:
**Lung lesions
**Lung lesions
***Clear demarcation of lesions in cranial and middle lobes
***Clear demarcation of lesions in cranial and middle lobes
***[[Lungs - inflammatory#Interstitial pneumonia|Interstitial pneumonia]]
***[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]
*Histologically:
*Histologically:
**Acute inflammation of mucosa of trachea and bronchi
**Acute inflammation of mucosa of trachea and bronchi
*Replicates in and destroys macrophages and endothelial cells causing vasculitis -> viraemia -> virus shedding (nasal secretions, faeces)
*Replicates in and destroys macrophages and endothelial cells causing vasculitis -> viraemia -> virus shedding (nasal secretions, faeces)
*Clinical signs: respiratory and reproductive failure, weaned pigs, tachypnoea, eyelid oedema, conjunctivitis
*Clinical signs: respiratory and reproductive failure, weaned pigs, tachypnoea, eyelid oedema, conjunctivitis
*Moderate to severe interstitial [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] in the cranial lobe
*Moderate to severe interstitial [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] in the cranial lobe
*Superimposed bacterial infections are common
*Superimposed bacterial infections are common
*Infectious disease in swine that emerged 10 years ago
*Infectious disease in swine that emerged 10 years ago
*Caused by a [[Circoviridae|porcine circovirus]] alone or in combination with [[Parvoviridae|porcine parvovirus]]
*Caused by a [[Circoviridae|porcine circovirus]] alone or in combination with [[Parvoviridae|porcine parvovirus]]
*May cause mild [[Lungs - inflammatory#Interstitial pneumonia|interstitial pneumonia]], failure of lungs to collpse on opening the thoracic cavity
*May cause mild [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]], failure of lungs to collpse on opening the thoracic cavity
*Microscopically: thickening of alveolar wall due to type 2 pneumocyte hyperplasia
*Microscopically: thickening of alveolar wall due to type 2 pneumocyte hyperplasia
*Caused by a [[Coronaviridae|coronavirus]]
*Caused by a [[Coronaviridae|coronavirus]]
*Usually mild [[Lungs - inflammatory#Infectious causes of pneumonia|pneumonia]] unless complicated by other agents
*Usually mild [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] unless complicated by other agents
*Virus replicates in epithelial lining of airways
*Virus replicates in epithelial lining of airways