Pathology: Respiratory

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Questions and Answers

What is the primary functional consequence of respiratory disease in domestic animals?

Improved defense mechanisms

Enhanced respiration efficiency

Economic losses in production (correct)

Increased nutritional intake

All respiratory diseases are caused by infections.

False

What is the medical term for the presence of blood in the nasal cavity?

Epistaxis

Pulmonary __________ refers to the collapse of lung tissue.

atelectasis Signup and view all the answers

Match the following terms with their definitions:

Rhinitis = Inflammation of the nasal mucosa Bronchiectasis = Dilation of the bronchi due to damage Pulmonary congestion = Excess fluid in the lungs Pulmonary edema = Accumulation of fluid in the lung tissue Signup and view all the answers

Which of the following factors is considered a common cause of pneumonia in domestic animals?

Viral infections Signup and view all the answers

Squamous metaplasia is a mechanism of repair in the respiratory system.

True Signup and view all the answers

Name one defense mechanism of the respiratory system.

Mucociliary clearance Signup and view all the answers

What is the primary purpose of the respiratory system?

Gas exchange Signup and view all the answers

The gas exchange system includes the trachea and bronchi.

False Signup and view all the answers

Name one type of cell that secretes pulmonary surfactant.

Type II pneumocytes Signup and view all the answers

The respiratory epithelium is predominantly made of ______ epithelium.

ciliated, pseudostratified, columnar Signup and view all the answers

Match the following structures with their respective functions:

Nasal cavity = Warm and humidify air Bronchioles = Conducting air to alveoli Alveoli = Gas exchange Larynx = Protect vocal cords Signup and view all the answers

Which of the following bacteria is notably pathogenic in the upper respiratory tract?

Mannheimia haemolytica Signup and view all the answers

Cilia in the respiratory tract help to move mucus toward the larynx.

True Signup and view all the answers

What is the role of club cells in the respiratory system?

Detoxify chemicals and regulate inflammatory response Signup and view all the answers

The conducting system is primarily responsible for removing particles with diameters between ______ μm from reaching the alveoli.

2 and 10 Signup and view all the answers

What structure surrounds bronchi and helps sample antigens in the mucus?

Bronchial-associated lymphoid tissue (BALT) Signup and view all the answers

What is one common cause of rhinitis in domestic animals?

Fungal infections Signup and view all the answers

Epistaxis refers to the accumulation of fluid in the lungs.

False Signup and view all the answers

List one important defense mechanism of the respiratory system.

Mucociliary clearance Signup and view all the answers

Pulmonary __________ is the term for inflammation of the lung tissue.

pneumonia Signup and view all the answers

Match the following respiratory conditions with their definitions:

Pulmonary congestion = Accumulation of fluid in the lungs Bronchiectasis = Abnormal dilation of the bronchi Pulmonary emphysema = Destruction of alveolar walls Bronchiolitis obliterans = Scarring and inflammation of the bronchioles Signup and view all the answers

Which type of pneumonia is characterized by inflammation that primarily affects the airspaces?

Bronchopneumonia Signup and view all the answers

Pulmonary oedema can result from increased hydrostatic pressure in the pulmonary circulation.

True Signup and view all the answers

What are the two main components of the respiratory system responsible for gas exchange?

Alveoli and capillaries Signup and view all the answers

What is the primary purpose of the respiratory system?

Gas exchange Signup and view all the answers

The gas exchange system includes the nasal cavity and pharynx.

False Signup and view all the answers

Name one major region where defence mechanisms of the respiratory system can be divided.

Conducting system, transitional system, exchange system Signup and view all the answers

The primary type of cell that secretes pulmonary surfactant is __________.

Type II pneumocytes Signup and view all the answers

Match the following structures with their primary functions:

Nasal cavity = Warms and humidifies inhaled air Trachea = Conducts air to bronchi Alveoli = Gas exchange site Bronchioles = Regulates airflow Signup and view all the answers

Which of the following cells are responsible for metabolizing and detoxifying chemicals?

Clara cells Signup and view all the answers

Mannheimia haemolytica is commonly found in the lower respiratory tract without causing disease.

False Signup and view all the answers

What is the role of the mucus blanket in the respiratory system?

To trap inhaled particles and pathogens Signup and view all the answers

The conducting system removes particles with diameters between _______ μm from reaching the alveoli.

2 and 10 Signup and view all the answers

In which part of the respiratory system is the defence mechanism particularly responsible for producing turbulent air-flow?

Nasal cavity Signup and view all the answers

Which virus is NOT known to cause equine viral rhinitis?

Equine influenza virus Signup and view all the answers

Equine viral rhinitis typically results in severe respiratory distress in horses.

False Signup and view all the answers

What is the causative agent of strangles in horses?

Streptococcus equi ssp. equi Signup and view all the answers

Strangles can lead to __________, which is the accumulation of pus in an enclosed space.

empyaema Signup and view all the answers

Match the following equine diseases with their characteristics:

Equine viral rhinitis = Caused primarily by viruses and is self-limiting Strangles = Caused by Streptococcus equi and can lead to lymph node enlargement Equine influenza = Causes outbreaks of mild disease and is not present in New Zealand Bacterial pneumonia = Can occur as a secondary infection after viral diseases Signup and view all the answers

Which of the following is NOT a potential sequela of strangles?

Chronic cough Signup and view all the answers

Secondary bacterial pneumonia can develop as a result of equine rhinitis.

True Signup and view all the answers

What is a common clinical sign of strangles in horses?

Purulent rhinitis Signup and view all the answers

Which horse breeds are most commonly affected by progressive ethmoidal hematoma?

Arabian and Thoroughbred Signup and view all the answers

Infectious bovine rhinotracheitis (IBR) is caused by a fungus.

False Signup and view all the answers

What is the primary cause of atrophic rhinitis in pigs?

Pasteurella multocida type D Signup and view all the answers

Fungal rhinitis in dogs is commonly due to infection by _______.

Aspergillus fumigatus Signup and view all the answers

Match the following conditions to their respective characteristics:

Progressive ethmoidal hematoma = Localized hemorrhage and possible bone destruction Infectious bovine rhinotracheitis = Caused by bovine herpesvirus 1 Atrophic rhinitis = Caused by Pasteurella multocida type D Feline viral rhinotracheitis = Caused by feline herpesvirus 1 Signup and view all the answers

What clinical signs are typically associated with progressive ethmoidal hematoma?

Mild epistaxis with coughing Signup and view all the answers

Secondary bacterial infections are not a concern in uncomplicated infectious bovine rhinotracheitis.

True Signup and view all the answers

What type of cells are predominantly observed in the cytological examination of nasal granulomas?

Eosinophils Signup and view all the answers

Canine fungal rhinitis is often associated with a guarded __________.

prognosis Signup and view all the answers

Which factor is known to influence the severity of atrophic rhinitis in pigs?

Genetics of the pig Signup and view all the answers

Fungal rhinitis is more common in short-nosed dogs.

False Signup and view all the answers

What is the condition characterized by high morbidity and low mortality in pigs younger than 5 weeks old?

Inclusion body rhinitis Signup and view all the answers

Chronic nasal discharge in bovine nasal granulomas is likely due to an allergic __________.

aetiology Signup and view all the answers

Match the disease to its primary viral agent:

Infectious bovine rhinotracheitis = Bovine herpesvirus 1 Feline viral rhinotracheitis = Feline herpesvirus 1 Inclusion body rhinitis = Cytomegalovirus family herpesvirus Atrophic rhinitis = Pasteurella multocida Signup and view all the answers

What is a potential consequence of FHV-1 infection in cats?

Bacterial sinusitis Signup and view all the answers

Feline calicivirus exclusively causes lesions related to the respiratory system.

False Signup and view all the answers

What is the primary organism that causes feline chlamydophilosis?

Chlamydophila felis Signup and view all the answers

The condition where cats develop __________ polyps is common in the nasopharynx.

nasopharyngeal Signup and view all the answers

What type of cancer is most frequently seen in the nasal area of cats?

Squamous cell carcinoma Signup and view all the answers

Chronic nasal disease is a common symptom of feline cryptococcosis.

True Signup and view all the answers

What are the clinical signs associated with nasal neoplasia in dogs?

Unilateral epistaxis and persistent nasal discharge Signup and view all the answers

FHV-1 can cause __________ keratitis in infected cats.

ulcerative Signup and view all the answers

What is a common characteristic of nasal cysts in horses?

They can be expansile. Signup and view all the answers

Brachycephalic airway syndrome is primarily due to enlarged nasal passages.

False Signup and view all the answers

What potential respiratory complication can arise from laryngeal edema?

Asphyxiation Signup and view all the answers

Feline calicivirus lesions include ulcerative _________ in the mouth.

stomatitis Signup and view all the answers

Match the condition with its corresponding causative agent:

FHV-1 = Feline herpesvirus Feline chlamydophilosis = Chlamydophila felis Feline cryptococcosis = Cryptococcus neoformans Feline calicivirus = Calicivirus Signup and view all the answers

Which of the following conditions can be caused by a secondary bacterial infection?

All of the above Signup and view all the answers

What is the primary cause of guttural pouch mycosis?

Inhalation of Aspergillus fumigatus spores Signup and view all the answers

Guttural pouch empyema is characterized by necrosis of the guttural pouch mucosa.

False Signup and view all the answers

What are the potential consequences of damage to the nerves near the guttural pouch?

Dysphagia, Horner’s syndrome, or laryngeal hemiplegia. Signup and view all the answers

The bacteria __________ is commonly associated with laryngeal necrobacillosis.

Fusobacterium necrophorum Signup and view all the answers

Match the disease with its characteristic feature:

Guttural pouch mycosis = Thick mats of fungal hyphae Guttural pouch empyema = Distension with pus Laryngeal necrobacillosis = Necrotizing toxins Canine tracheobronchitis = Contagious with multiple agents Signup and view all the answers

What clinical signs are associated with laryngeal necrobacillosis?

Dysphagia and halitosis Signup and view all the answers

Canine tracheobronchitis is typically caused by a single infectious agent.

False Signup and view all the answers

What is the most common origin of pulmonary atelectasis in newborn animals?

Aspiration of meconium Signup and view all the answers

Pulmonary congestion is most commonly seen in cases of __________ heart failure.

left-sided Signup and view all the answers

What can exacerbate the clinical signs of canine tracheobronchitis?

Stress and poor ventilation Signup and view all the answers

Atelectasis refers specifically to the irreversible collapse of alveoli.

False Signup and view all the answers

What pathological changes might be observed in the lungs with pulmonary congestion?

Dark red lungs in acute cases; tan-colored in chronic cases. Signup and view all the answers

Match the type of atelectasis with its description:

Congenital atelectasis = Aspiration of meconium Compressive atelectasis = External pressure on the lung Obstructive atelectasis = Blocked airway Acute atelectasis = Reversible alveolar collapse Signup and view all the answers

Pulmonary __________ is the term used for the accumulation of fluid in the lungs.

oedema Signup and view all the answers

What is a common sign of pulmonary atelectasis during a necropsy examination?

Lungs feel meaty or heavy. Signup and view all the answers

What is the primary cause of pulmonary emphysema in animals?

Increased inspiratory effort Signup and view all the answers

Pulmonary hemorrhage can occur due to anticoagulant toxicity.

True Signup and view all the answers

What are the three subclassifications of human emphysema?

alveolar, interstitial, bullous Signup and view all the answers

Pulmonary __________ is defined as the overinflation of alveoli with destruction of the alveolar wall.

emphysema Signup and view all the answers

Match the following conditions with their causes:

Bronchopneumonia = Inhaled bacteria Pulmonary edema = Increased capillary permeability Pulmonary embolism = Neoplastic or septic emboli Exercise-induced pulmonary hemorrhage = Alveolar hypoxia Signup and view all the answers

Which type of pneumonia usually shows consolidation in the cranioventral parts of the lung?

Bronchopneumonia Signup and view all the answers

Lung abscesses have no relationship with pulmonary hemorrhage.

False Signup and view all the answers

What can cause pulmonary edema other than hydrostatic pressures?

Increased permeability of alveolar capillaries Signup and view all the answers

Thorax opened lungs with interstitial pneumonia appear __________ and have visible rib imprints.

over-expanded Signup and view all the answers

Match the following agents to their effects in pneumonia:

Necrotic agents = Severe necrosis and leakage of fibrin Viral agents = Increased capillary permeability Bacterial agents = Cause bronchopneumonia Toxins = Marked necrosis Signup and view all the answers

What is a common cause of exercise-induced pulmonary hemorrhage in racehorses?

Pulmonary hypertension Signup and view all the answers

Pulmonary embolism generally leads to significant lung infarcts in animals.

False Signup and view all the answers

What is one characteristic gross appearance of oedematous lungs?

Diffuse, wet, shiny appearance Signup and view all the answers

Pulmonary __________ is characterized by the presence of bronchiolar necrosis and alveolar damage.

bronchointerstitial pneumonia Signup and view all the answers

Which of the following is a common cause of embolic pneumonia?

Tumor emboli Signup and view all the answers

Granulomatous pneumonia is caused by inhaled fungi and higher bacteria.

True Signup and view all the answers

What type of pneumonia results from the aspiration of stomach contents?

Aspiration pneumonia Signup and view all the answers

The bacteria responsible for bovine tuberculosis is __________.

M. bovis Signup and view all the answers

Match the disease to its causative agent:

Tuberculosis = Mycobacterium spp. Cryptococcosis = Cryptococcus neoformans Aspiration pneumonia = Stomach contents Parasitic pneumonia = Lungworms Signup and view all the answers

Which type of pneumonia shows grossly similar features to embolic pneumonia?

Granulomatous pneumonia Signup and view all the answers

Pulmonary calcification is always clinically significant.

False Signup and view all the answers

Name a primary disease process that could predispose an animal to aspiration pneumonia.

Cleft palate Signup and view all the answers

In dogs, pulmonary calcification can occur due to __________ or toxicity with rodenticides.

renal secondary hyperparathyroidism Signup and view all the answers

Which of the following is NOT commonly associated with tuberculosis in animals?

High mortality in horses Signup and view all the answers

Cryptococcus neoformans is often found in the lungs of cats.

True Signup and view all the answers

What is the primary site of infection for Cryptococcosis?

Lungs Signup and view all the answers

In cattle, heavy infestations of lungworm can result in __________.

coughing and dyspnea Signup and view all the answers

What histological feature characterizes granulomatous pneumonia?

Foci of epithelioid macrophages Signup and view all the answers

What type of pneumonia is primarily associated with porcine circovirus and post-weaning multisystemic wasting syndrome (PMWS)?

Granulomatous interstitial pneumonia Signup and view all the answers

Distemper is known to cause secondary bacterial bronchopneumonia in affected dogs.

True Signup and view all the answers

What is a common clinical sign of canine distemper?

Mucopurulent nasal discharge Signup and view all the answers

The necrotizing lesions in pleuropneumonia primarily affect the __________ areas of the lung.

caudodorsal Signup and view all the answers

Match the disease with its causative agent:

Distemper = Morbillivirus PMWS = Porcine circovirus (PCV-2) Canine bacterial pneumonia = Various bacteria including Pasteurella multocida Acute fibrinous pneumonia = Ovine and bovine pathogens Signup and view all the answers

Which of the following statements is correct about the effects of distemper on the body?

It can affect the nervous system and lead to demyelination. Signup and view all the answers

Affected pigs with PMWS often show marked lymphadenopathy.

True Signup and view all the answers

What can be a consequence of distemper infection weeks after the onset of clinical signs?

Neurologic signs of demyelination Signup and view all the answers

What bacterium is primarily associated with pneumonia in calves?

Mycoplasma bovis Signup and view all the answers

Chronic pneumonia caused by Mycoplasma bovis is generally responsive to treatment.

False Signup and view all the answers

Name one disease syndrome associated with Mycoplasma bovis infection.

arthritis Signup and view all the answers

Bovine acute fibrinous pneumonia is also known as __________ fever.

Shipping Signup and view all the answers

What are the two respiratory toxins occasionally seen in New Zealand?

4-ipomeanol and L-tryptophan Signup and view all the answers

4-ipomeanol is commonly found in mouldy kumara.

True Signup and view all the answers

What is the histological feature observed in bovine acute fibrinous pneumonia?

marked necrosis Signup and view all the answers

Damage to type I pneumocytes due to toxins leads to __________ and interstitial oedema.

alveolar Signup and view all the answers

Match the diseases with their causative bacteria:

Enzootic pneumonia = Mycoplasma bovis Shipping fever = Mannheimia haemolytica Toxic pneumonia = 4-ipomeanol Acute respiratory disease = Pasteurella multocida Signup and view all the answers

What condition is often called fog fever?

L-tryptophan intoxication Signup and view all the answers

What is the primary type of lung lesion associated with Muellerius capillaris in sheep?

Nodular grey-green or calcified subpleural nodules Signup and view all the answers

Which of the following conditions is characterized by a severe form of pneumonia with higher mortality?

Bovine acute fibrinous pneumonia Signup and view all the answers

Aelurostrongylus abstrusus typically results in visible clinical signs of disease in domestic cats.

False Signup and view all the answers

Which respiratory disease is commonly referred to as 'equine shipping fever'?

Equine bacterial pneumonia and pleuropneumonia Signup and view all the answers

Mortierella wolfii infects non-pregnant cows asymptomatically.

True Signup and view all the answers

The respiratory form of equine viral rhinopneumonitis is generally described as ______ pneumonia.

bronchointerstitial Signup and view all the answers

The pathogenesis of both 4-ipomeanol and L-tryptophan involves the production of __________ by Club cells.

free radicals Signup and view all the answers

Match the following diseases with their main characteristics:

Muellerius capillaris = Nodular lungworm infection Aelurostrongylus abstrusus = Infestation causing coughing and dyspnea Equine viral rhinopneumonitis = Respiratory disease of young horses Rhodococcosis = Pyogranulomatous pneumonia in immunocompromised Signup and view all the answers

What is usually the first sign of respiratory distress in cattle affected by toxic pneumonia?

dyspnoea Signup and view all the answers

What factor is commonly associated with the development of heaves in horses?

Exposure to airborne organic dust Signup and view all the answers

What is the effect of bacterial toxins from Mannheimia haemolytica on lungs?

Induce necrosis of surrounding tissue Signup and view all the answers

Histologically, equine bacterial pneumonia is characterized by the presence of large quantities of clear fluid.

False Signup and view all the answers

What is the main causative agent of rhodococcosis in horses?

Rhodococcus equi Signup and view all the answers

Bovine enzootic pneumonia is also known as ______ pneumonia.

calf Signup and view all the answers

Match the following clinical signs with the appropriate respiratory disease:

Coughing and dyspnea = Aelurostrongylus abstrusus infestation Recurrent respiratory distress = Heaves Acute pneumonia = Rhodococcosis Severe enterocolitis = Rhodococcosis Signup and view all the answers

What is a potential complication of equine viral rhinopneumonitis?

Secondary bacterial infections Signup and view all the answers

Toxoplasmosis is frequently fatal in animals with normal immune function.

False Signup and view all the answers

What type of pneumonia is characterized by consolidations in the cranioventral parts of the lungs?

Bronchopneumonia Signup and view all the answers

Rhodococcus equi has the ability to live inside ______.

macrophages Signup and view all the answers

What is the most significant cause of abortion in cattle in the North Island of New Zealand?

Mortierella wolfii Signup and view all the answers

Ovine enzootic pneumonia is primarily responsible for severe clinical signs in sheep older than one year.

False Signup and view all the answers

What is a common clinical sign of porcine pleuropneumonia?

Severe respiratory distress Signup and view all the answers

Mortierella is a significant cause of bovine abortion and subsequent pneumonia in __________.

New Zealand Signup and view all the answers

Match the following bacteria with their associated diseases:

Aspergillus = Mycotic abortion Mannheimia haemolytica = Ovine acute fibrinous pneumonia Mycoplasma hyopneumoniae = Porcine enzootic pneumonia Actinobacillus pleuropneumoniae = Porcine pleuropneumonia Signup and view all the answers

Which of these factors is NOT known to predispose cattle to respiratory disease?

Excessive hydration Signup and view all the answers

Histological examination of necropsy samples from cattle with necrotic pneumonia show large quantities of neutrophils.

True Signup and view all the answers

What is the causative agent of porcine pleuropneumonia?

Actinobacillus pleuropneumoniae Signup and view all the answers

The disease known as 'chronic non-progressive pneumonia' affects animals less than ____ year of age.

1 Signup and view all the answers

What is the primary histological observation in necropsy samples from cattle affected by Mortierella?

Fungal hyphae Signup and view all the answers

Sheep rarely experience mortality due to ovine enzootic pneumonia.

True Signup and view all the answers

What is often the predominant clinical sign in sheep affected by chronic non-progressive pneumonia?

Decreased weight gain Signup and view all the answers

Cattle can develop fatal embolic pneumonia after abortion due to __________ infection.

Mortierella wolfii Signup and view all the answers

Match the following diseases with their characteristics:

Ovine enzootic pneumonia = Mild pneumonia in animals less than 1 year of age Porcine enzootic pneumonia = Economically important respiratory disease of pigs Ovine acute fibrinous pneumonia = Sporadic and typically fatal disease Porcine pleuropneumonia = Caused by Actinobacillus pleuropneumoniae Signup and view all the answers

Study Notes

Respiratory Diseases in Domestic Animals

Respiratory disease is prevalent in food animals and equines; significant in shelter medicine and North American agriculture.
Causes substantial economic losses in production animals; relatively less severe in New Zealand.
Common reason for veterinary consultations concerning food animals.

Respiratory System Structure and Function

Primary role: gas exchange (oxygen absorption, carbon dioxide excretion).
Requires frequent air change, a large diffusion area, warm and moist membranes, dense capillary networks, and thin capillary walls.
Divided into three systems:
- Conducting System: Includes nasal cavity, pharynx, larynx, trachea, bronchi; no gas exchange function.
- Transitional System: Composed of bronchioles.
- Gas Exchange System: Alveoli responsible for actual gas exchange.

Microanatomy of the Respiratory System

Conducting System: Lined with ciliated, pseudostratified columnar epithelium; features mucous-secreting goblet and serous cells; essential for lung defenses.
Transitional System: Ciliated cells decrease, goblet cells diminish, columnar cells become flattened; club and basal cells act as progenitors and detoxify harmful agents.
Gas Exchange System: Contains type I and type II pneumocytes; type I facilitates gas exchange, while type II secretes pulmonary surfactant.

Normal Flora and Defense Mechanisms

Resident bacteria present in nasal cavity, pharynx, and larynx; high chance of mixed bacterial populations during culture.
Pathogenic bacteria like Mannheimia haemolytica may reside harmlessly but can cause severe disease when entering the lungs.
Defense mechanisms segmented into:
- Conducting System: Traps larger particles using turbulent airflow and mucus; ciliary action moves mucus to the larynx.
- Exchange System: Designed to engage with smaller inhaled particles, crucial for maintaining lung integrity.

Common Respiratory Pathologies

Rhinitis: Defined by morphological features; common causes include viral, bacterial, and environmental factors.
Epistaxis, Pulmonary Congestion, Atelectasis, Emphysema: Defined conditions with specific pathophysiological implications.
Bronchopneumonia, Interstitial Pneumonia, and Others: Classified by morphology and etiology; each type has distinct features and pathogenesis.

Mechanisms of Injury and Repair

Injury may result in squamous metaplasia, bronchiectasis, and bronchiolitis obliterans.
Repair mechanisms play a significant role in recovering lung function post-injury.

Neoplasms and Cytological Evaluation

Recognize common neoplasms affecting the respiratory system.
Proper evaluation of cytology samples is crucial; interpretation aids in developing differential diagnoses for various respiratory conditions.

Classification of Respiratory Diseases

Uses a scale from rare and less important (1) to common and significant (5), aiding in prioritizing clinical focus.

Respiratory Diseases in Domestic Animals

Respiratory disease is prevalent in food animals and equines; significant in shelter medicine and North American agriculture.
Causes substantial economic losses in production animals; relatively less severe in New Zealand.
Common reason for veterinary consultations concerning food animals.

Respiratory System Structure and Function

Primary role: gas exchange (oxygen absorption, carbon dioxide excretion).
Requires frequent air change, a large diffusion area, warm and moist membranes, dense capillary networks, and thin capillary walls.
Divided into three systems:
- Conducting System: Includes nasal cavity, pharynx, larynx, trachea, bronchi; no gas exchange function.
- Transitional System: Composed of bronchioles.
- Gas Exchange System: Alveoli responsible for actual gas exchange.

Microanatomy of the Respiratory System

Conducting System: Lined with ciliated, pseudostratified columnar epithelium; features mucous-secreting goblet and serous cells; essential for lung defenses.
Transitional System: Ciliated cells decrease, goblet cells diminish, columnar cells become flattened; club and basal cells act as progenitors and detoxify harmful agents.
Gas Exchange System: Contains type I and type II pneumocytes; type I facilitates gas exchange, while type II secretes pulmonary surfactant.

Normal Flora and Defense Mechanisms

Resident bacteria present in nasal cavity, pharynx, and larynx; high chance of mixed bacterial populations during culture.
Pathogenic bacteria like Mannheimia haemolytica may reside harmlessly but can cause severe disease when entering the lungs.
Defense mechanisms segmented into:
- Conducting System: Traps larger particles using turbulent airflow and mucus; ciliary action moves mucus to the larynx.
- Exchange System: Designed to engage with smaller inhaled particles, crucial for maintaining lung integrity.

Common Respiratory Pathologies

Rhinitis: Defined by morphological features; common causes include viral, bacterial, and environmental factors.
Epistaxis, Pulmonary Congestion, Atelectasis, Emphysema: Defined conditions with specific pathophysiological implications.
Bronchopneumonia, Interstitial Pneumonia, and Others: Classified by morphology and etiology; each type has distinct features and pathogenesis.

Mechanisms of Injury and Repair

Injury may result in squamous metaplasia, bronchiectasis, and bronchiolitis obliterans.
Repair mechanisms play a significant role in recovering lung function post-injury.

Neoplasms and Cytological Evaluation

Recognize common neoplasms affecting the respiratory system.
Proper evaluation of cytology samples is crucial; interpretation aids in developing differential diagnoses for various respiratory conditions.

Classification of Respiratory Diseases

Uses a scale from rare and less important (1) to common and significant (5), aiding in prioritizing clinical focus.

Equine Viral Rhinitis

Caused by various agents including Equine herpesvirus types 1 and 4, rhinoviruses, adenoviruses, and parainfluenza virus.
Infections are generally mild and self-limiting, with transient effects on athletic performance.
Equine influenza is absent in New Zealand, with outbreaks usually resolving spontaneously.
Secondary bacterial pneumonia may occur due to initial viral infections.

Strangles

A systemic bacterial disease caused by Streptococcus equi ssp. equi.
Infection occurs when immune-naïve horses inhale bacteria from an infected individual, leading to rhinitis and lymphadenopathy.
Characteristic clinical signs include purulent rhinitis, conjunctivitis, and lymph node enlargement.
Potential complications include bastard strangles (hematogenous spread), purpura hemorrhagica (immune-complex vasculitis), bronchopneumonia, guttural pouch empyema, and neurological signs.

Progressive Ethmoidal Hematoma

Develops on the ethmoidal conchae, particularly common in older Arabian and Thoroughbred horses.
Thought to arise from minor hemorrhage causing chronic localized episodes.
Early signs include mild epistaxis and coughing, with possible bone deformity as the hematoma progresses.
Diagnosis requires biopsy to exclude fungal or neoplastic diseases; surgical excision is challenging with a recurrence rate of 30-50%.

Infectious Bovine Rhinotracheitis

Caused by bovine herpesvirus type 1 (BHV-1), an important viral respiratory pathogen.
Characterized by rhinitis and potential for secondary bacterial bronchopneumonia.
Grossly presents as areas of ulceration in the nasal cavity; inclusion bodies may be present transiently.
Latent virus can reactivate with immunosuppression, with North American strains being more pathogenic.

Bovine Nasal Granulomas

Likely to have an allergic etiology, presenting as chronic nasal discharge with eosinophilic predominance.
Initially appear as pink polypoid nodules at the rostral aspect of the nasal cavity.
Nasal irritation from foreign materials can cause necrotizing rhinitis.

Atrophic Rhinitis in Pigs

Affecting about one-third of pigs in New Zealand, particularly between 5-8 months of age.
Caused by toxin-producing Pasteurella multocida type D, often following concurrent infections or environmental factors.
Results in turbinate atrophy and nasal deformity; genetics and other infections influence disease severity.

Inclusion Body Rhinitis in Pigs

Caused by a herpesvirus affecting mainly pigs younger than 5 weeks.
Characterized by lymphocytic rhinitis with intranuclear inclusions; most recover after 2 weeks.
Rarely complicated by bronchopneumonia.

Canine Fungal Rhinitis

Commonly associated with Aspergillus fumigatus in middle-aged dogs.
Characterized by chronic unilateral purulent or hemorrhagic discharge; biopsy may be needed for definitive diagnosis.
Often difficult to treat, with a guarded prognosis.

Feline Viral Rhinotracheitis

Caused by feline herpesvirus 1 (FHV-1), leading to rhinitis and conjunctivitis, sometimes severe.
Persistent infection with intermittent shedding occurs, especially during stress.
Can lead to bacterial bronchopneumonia and sinusitis, causing turbinate lysis and permanent olfactory damage.

Feline Calicivirus

Causes lesions similar to FHV-1, along with bronchiolitis and ulcerative stomatitis.
Generally transient, with recovery expected unless secondary bacterial infections arise.

Feline Chlamydophilosis

Resulting from Chlamydophila felis, typically mild with potential for secondary bacterial infections.

Feline Cryptococcosis

Caused by Cryptococcus neoformans, leading to chronic nasal disease and various systemic manifestations.
Histologically characterized by a non-staining capsule with a "soap-bubble" appearance.

Non-neoplastic Lesions

Nasal polyps are common in horses (ethmoidal region) and cats (nasopharynx), often benign and removable surgically.
Horses can develop nasal cysts from trapped epithelium, which must be differentiated from neoplasia.

Nasal Neoplasia

Most prevalent in dogs, with malignant adenocarcinomas being the most common type.
Clinical signs include unilateral epistaxis, persistent nasal discharge, and possible secondary infections.

Brachycephalic Airway Syndrome

Results from anatomical abnormalities leading to airflow resistance and potential respiratory distress, particularly in bulldogs.
Other associated issues include hypoplastic epiglottis and dorsal displacement of the soft palate in horses.

Pharyngeal, Laryngeal, and Tracheal Oedema

Laryngeal oedema can obstruct airflow, often due to inflammatory responses or systemic anaphylaxis.

Guttural Pouch Disease

Involves mycosis from Aspergillus fumigatus or empyema secondary to strangles.
Guttural pouch mycosis can lead to severe hemorrhage if adjacent arteries are compromised.

Laryngeal Necrobacillosis

Also known as calf diphtheria; occurs after laryngeal mucosa damage leading to necrosis by Fusobacterium necrophorum.
Often fatal, clinical signs include dysphagia, halitosis, and dyspnoea.

Canine Tracheobronchitis

Highly contagious, referred to as kennel cough; commonly affects unvaccinated dogs with multiple causative agents.
Results primarily in coughing but can lead to secondary bronchopneumonia.

Pulmonary Congestion and Atelectasis

Pulmonary congestion indicates left-sided heart failure, with acute and chronic presentations noted.
Atelectasis involves collapse of alveoli categorized into congenital, compressive, and obstructive types, each with specific causes and clinical implications.### Obstructive Atelectasis
Localized lung involvement due to blocked airways caused by factors like inflammation, foreign material, parasites, or tumors.
Prolonged recumbency, particularly during anesthesia, can lead to diffuse obstructive pulmonary atelectasis.

Pulmonary Emphysema

Defined as overinflation of alveoli with destruction of their walls.
Primarily a secondary condition in animals, often arising from increased inspiratory effort, commonly linked to bronchopneumonia and recurrent airway obstruction in horses.
Human emphysema sub-classifications include alveolar, interstitial, and bullous variants, which are less applicable in veterinary pathology.

Pulmonary Hemorrhage

Results from trauma or anticoagulant toxicity, occasionally causing sudden massive hemorrhage due to lung abscesses.
Commonly observed in racehorses with exercise-induced pulmonary hemorrhage (EIPH); pathogenesis involves alveolar hypoxia and pulmonary hypertension.

Pulmonary Edema

Can occur due to increased permeability of alveolar capillaries, along with notable hemodynamic causes.
Associated with viral infections, toxic pneumonia, anaphylactic shock, and disseminated intravascular coagulation (DIC).
Visual examination reveals heavy, wet, and shiny lungs with abundant stable foam in bronchi.

Pulmonary Embolism

Common site for emboli, including neoplastic and septic types, due to significant pulmonary blood flow.
Generally does not cause significant lung infarcts in animals due to a dual blood supply; contrast to humans with larger thrombi from deep leg veins.
Septic emboli often stem from liver abscesses and right-sided endocarditis.

Bronchopneumonia

Inflammation primarily focuses on terminal bronchioles, frequently due to inhaled bacteria or aspirated material.
Characterized by consolidation in cranioventral lung areas, appearing dark red and heavy; may sink in water.
Histological signs include neutrophils and necrotic debris within bronchioles and expanded alveoli.

Interstitial Pneumonia

Lungs exhibit a firm texture and diffuse over-expansion due to inflammation in the alveolar interstitium, preventing alveolar collapse.
Pathogenesis involves either aerogenous or hematogenous injury to the alveolar tissue.
Less common than other pneumonia types; can lead to chronic fibrous tissue deposition and may result from viral infections or toxins.

Embolic Pneumonia

Characterized by scattered foci of consolidation from emboli originating from the bloodstream, rather than infection directly entering the lungs.
Common causes include vegetative endocarditis and liver abscesses, appearing histologically as either septic inflammation or neoplastic cell proliferation.

Granulomatous Pneumonia

Distinctive for granuloma formation due to inhalation of certain fungi or bacteria.
Commonly involves agents like Rhodococcus equi and Mycobacterium species.
Histological foci contain epithelioid macrophages and multinucleate giant cells.

Metabolic Disturbances

Pulmonary calcification occurs, frequently due to renal disease or toxin exposure; classified by gritty lung texture.
Usually, pulmonary calcification is not clinically significant unless indicating underlying renal issues.

Aspiration Pneumonia

Results from inhalation of foreign materials, often stomach contents; can be iatrogenic.
Severity depends on the nature of the aspirated material, ranging from mild inflammation (bland substances) to severe necrosis (caustic substances).

Tuberculosis

Caused by Mycobacterium spp., varying across animal species in susceptibility.
Commonly leads to chronic, caseating granulomas in lungs and lymph nodes, with potential progression to other organs.

Cryptococcosis

Resulting from inhalation of Cryptococcus neoformans; primarily affects cats but can impact other species.
Often asymptomatic until it disseminates, leading to granulomas in the skin or nasal area.

Parasitic Pneumonias

Lungworm infections are common but usually do not cause significant illness; certain species like Dictyocaulus can cause severe issues, particularly in calves.
Subclinical infections in cats with Aelurostrongylus can sometimes lead to noticeable respiratory symptoms.

Equine Viral Rhinopneumonitis (EVR)

Caused by equine herpesvirus, affecting primarily young horses, presenting mild bronchointerstitial pneumonia unless complicated by bacterial infections.

Rhodococcosis

Primarily affects foals and immunocompromised adults due to Rhodococcus equi; presents with pyogranulomatous pneumonia and enterocolitis.
May spread systemically leading to severe illness and has zoonotic potential.

Heaves (Recurrent Airway Obstruction)

Airway disorder in horses characterized by hypersensitivity and obstruction, often triggered by environmental factors.
Symptoms include chronic cough, exercise intolerance, and respiratory distress, with associated lung histology showing goblet cell hyperplasia and inflammation.

Equine Bacterial Pneumonia

Also known as shipping fever, it follows transportation stresses or viral infections.
Caused by opportunistic bacteria leading to severe clinical signs, which may be exacerbated by aspiration.

Bovine Enzootic Pneumonia

Common in calves, caused by multiple infectious agents and environmental stressors.
Predisposes to secondary bacterial infections, leading to significant morbidity and occasional mortality.

Mycoplasma bovis Pneumonia

An important pathogen in calf respiratory disease, often resulting in chronic pneumonia unresponsive to treatment.
Associated with various clinical syndromes including arthritis and mastitis alongside pneumonia.

Bovine Acute Fibrinous Pneumonia

Considered a severe form of shipping fever, with low morbidity but high mortality rates.
Primarily impacts older cattle, leading to significant respiratory distress.### Shipping Fever
Commonly affects cattle during transport to feedlots in North America.
Induced by factors like weaning, mixing animals, fatigue, and dehydration, compromising respiratory defenses.
Toxigenic strains of Mannheimia haemolytica and Pasteurella multocida invade the lungs post-compromise.
Bacterial toxins inhibit inflammatory response leading to necrosis and pleuropneumonia.
Symptoms include depression, fever, shallow cough; necropsy reveals cranioventral consolidation with fibrin.
Histology shows necrosis, degenerate neutrophils, and expansion of interlobular septa by edema and fibrin.
Survival may result in pulmonary abscesses; pathogenicity relies on the level of respiratory defense impairment.

Toxic Pneumonia

Caused by toxins like 4-ipomeanol (from mouldy kumara) and L-tryptophan (from re-growing pastures).
L-tryptophan metabolizes to 3-methylindole in the rumen, leading to free radical production and damage to type I pneumocytes.
Results in interstitial pneumonia characterized by alveolar and interstitial edema.
Clinical signs develop 1-2 weeks post-exposure with necropsy revealing diffusely enlarged lungs with rib imprints.
Histology shows interstitial edema, fibrin, and type II pneumocyte hyperplasia if the animal survives.

Mortierella Wolfii

Environmental fungus that asymptomatically infects non-pregnant cows but causes severe placentitis and abortion in pregnant cows.
Fungi can embolize to lungs post-abortion, causing necrotizing pneumonia.
Necropsy may reveal hemorrhage and fibrin in the pleural cavity, with cattle typically dying within 2 days of respiratory clinical signs.
Histological examination shows necrotic cell debris, edema, and fungal hyphae; significant fatality in cases following abortion.

Ovine Enzootic Pneumonia

Also known as chronic non-progressive pneumonia, it affects primarily sheep under one year.
Predisposed by viral infections (parainfluenza, adenovirus) and stressors like dehydration and dusty conditions.
Bacterial invaders include Mycoplasma ovipneumoniae and P.multocida leading to bronchopneumonia.
Clinical signs include coughing and reduced weight gain; typically not fatal.
Necropsy findings show mild cranioventral consolidation, possibly with fibrin facilitating fibrous tags formation.

Ovine Acute Fibrinous Pneumonia

Sporadic and severe, similar to shipping fever in cattle.
Caused by Mannheimia haemolytica under viral infection and stress conditions.
Histological findings mirror those of shipping fever with marked cranioventral pleuropneumonia.

Porcine Enzootic Pneumonia

Most economically significant respiratory disease in pigs caused by Mycoplasma hyopneumoniae.
Infection requires compromised respiratory defenses from environmental stressors like crowding and humidity.
Clinically, pigs exhibit chronic cough and stunted growth, with necropsy revealing cranioventral consolidation.
Histological observations include neutrophils, necrotic debris, and bronchial-associated lymphoid tissue hyperplasia.

Porcine Pleuropneumonia

Caused by Actinobacillus pleuropneumoniae; unique as it can cause disease with intact respiratory defenses.
Primarily affects caudodorsal lung regions in pigs aged 2 to 5 months, resulting in severe respiratory distress.
Produces potent toxins leading to alveolar wall necrosis and subsequent pleuropneumonia.
Histologically similar to diseases in cattle, showcasing necrotizing lesions.

Porcine Circovirus and PMWS

Caused by PCV-2, requiring undiscovered additional factors for disease manifestation.
Results in granulomatous interstitial pneumonia manifesting as diffuse lung expansion.
Systemic effects include lymphadenopathy and emaciation, often leading to death from secondary bacterial pneumonia.

Distemper

Caused by morbillivirus; spreads from inhalation to local lymphoid tissue before systemic dissemination.
Immunosuppressive, leading to interstitial pneumonia and susceptibility to secondary infections.
Common clinical signs: mucopurulent nasal discharge, coughing, and respiratory distress; can affect multiple organ systems.
Diagnosis relies on histology showing eosinophilic inclusions in epithelial tissues.

Canine Bacterial Pneumonia

Caused by various bacteria including Pasteurella multocida, Streptococcus sp, and E. coli.
Most often secondary to aspiration pneumonia, highlighting risk in vulnerable dogs.

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Description

Explore the critical aspects of respiratory diseases in domestic animals, including their economic impact and significance in veterinary medicine. Learn about the structure and function of the respiratory system and its microanatomy, which are crucial for understanding gas exchange.