Path 1.1 respiratory illanes


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Path 1.1 respiratory illanes

  1. 1. Oscar G.Illanes,DVM,PhD,DACVP Department of Pathobiology Pathology of the Respiratory System Disclaimer: Images from this presentation come from different sources: Mc Gavin ‘s Pathologic Basis of Veterinary Disease, Dr. King files, Noah’s arkive ,OVC, AVC, author’s own files etc. This presentation is for teaching purposes only, please do not distribute.
  2. 2. General objectives  Overview of the diseases that affect the respiratory system of domestic animals  Emphasis on:  how to recognize the morphologic changes present within tissues in specific diseases/ conditions  most common respiratory diseases  how to arrive to the proper morphologic or etiologic diagnosis for the lesion  Disease pathogenesis, if known  Differential diagnosis, if applicable.
  3. 3. References  A. Lόpez:“ Respiratory System” in Pathologic Basis ofVeterinary Disease, McGavin & Zachary, editors, 5th ed., Mosby, p458-, 2012  J Caswell & K.Williams:“Respiratory System” in JKP Pathology of Domestic Animals,Vol 2, edited by MG Maxie, 5th ed., Saunders, p523-653, 2007
  4. 4. Anatomic division of the respiratory tract Upper & Lower respiratory tract. In general the upper respiratory tract is the portion of the respiratory system located outside the thoracic cavity.
  5. 5. Physiologically the respiratory tract is divided into three independent but continuous systems: 1.- Conducting system: Includes the nasal cavity, paranasal sinuses, larynx, trachea and bronchi.The mucosa of this system is primarily lined by pseudostratified ciliated epithelium and goblet cells. 2.-Transitional system : consists exclusively of bronchioles which are lined by Clara cells (detoxification of xenobiotics), non-ciliated secretory cells and only a few ciliated cells. Healthy bronchioles do not have goblet cells.
  6. 6. 3. Exchange system: Composed of alveolar ducts and millions of alveoli; thin-walled structures enveloped by a rich network of capillaries, the pulmonary capillaries. Alveoli are lined by epithelial type I (membranous) and type II (granular) pneumocytes (also called pneumonocytes). Each of these systems has a characteristic susceptibility to injury and specific type of host response and repair.
  7. 7. The lungs have a dual blood supply: Through the pulmonary arteries which conduct deoxygenated blood from the right side of the heart, and the bronchial arteries, which carry oxygenated blood.
  8. 8.  In addition to gas exchange, the respiratory system is also involved in phonation, olfaction, temperature regulation, acid–base balance, blood pressure regulation etc.  Several of these functions may be affected by respiratory disease.
  9. 9. Pictures from Dr. Thomas Caceci’s histology Web site.
  10. 10. Pictures from Dr. Thomas Caceci’s histology Web site.
  11. 11. Normal Flora – Restricted only to the most proximal region of the conductive system: nasal cavity, nasopharynx, larynx and trachea. The distal portions of the respiratory tract are considered to be sterile.
  12. 12.  Even though the majority of the organisms of the normal respiratory flora are harmless others are potentially pathogenic; e.g.: Mannheimia haemolytica,Bordetella bronchiseptica.
  13. 13. “The air that we inhale every day in a healthy environment contains billions of suspended particles, spores, bacteria, viruses and noxious gases that are constantly carried deep into the lungs”...Fortunately the lungs have a very efficient defence system to deal with the environmental hazards present under normal conditions.
  14. 14. Experimental studies have demonstrated that bacteria from the nasal flora, including some potentially important pathogens, are constantly being carried into the lungs by inspired air. In spite of this constant bacterial bombardment, the lower respiratory tract remains essentially sterile due to the presence of highly effective respiratory defence mechanisms.
  15. 15. Defence mechanisms of the respiratory system  Non-specific (non immune- mediated):  Mucous trapping  Mucociliary clearance (mucociliary escalator)  Phagocytosis  Air turbulence (generated by coughing and sneezing).  Specific (immune-mediated):  Antibody production  Antibody-mediated phagocytosis  Cell-mediated immunity
  16. 16. Pulmonary Macrophages  Alveolar Macrophages (“PAMs”)  Intravascular Macrophages (“PIMs”> ruminants,cats,pigs and horses) In dogs, humans and laboratory rodents the cells responsible for removing circulating bacteria and other particles from blood are the Kupffer cells (liver) and splenic macrophages.
  17. 17. ..From the web 
  18. 18.  Animals suffering from a respiratory viral infection have notably suppressed defence mechanisms which make them susceptible to bacterial colonization within the airways.  Viruses are not the only factor known to predispose to bacterial pneumonia, other causes are:  Stress  Dehydration  Pulmonary edema  Uremia  Ammonia  Immunosuppression/ immunodeficiency
  19. 19. Post-mortem examination of the respiratory tract Horse-UCVM-09 Thorough systematic examination and appropriate sampling are very important. Microbiology results should always be interpreted carefully taken into account clinical and post-mortem findings.
  20. 20. Pig, normal lungs, AVC
  21. 21. Nasal cavity
  22. 22. Ethmoidal hematoma – cause of epistaxis in horses Pedunculated tumor-like lesion in older horses.The exact etiology of this lesion is unknown. Dr.King’s show & Tell
  23. 23. Fibrinous rhinitis – mid-sagittal section of the head – Calf with IBR Infectious Bovine Rhinotracheitis (formation of diphtheritic membrane)
  24. 24. Oestrus ovis, nasal bot in sheep – worldwide distribution From McGavin, Zachary.
  25. 25. Aberrant migration of Oestrus ovis larva, sheep-TexasA&M.
  26. 26. Atrophic rhinitis in pigs. Multifactorial disease in growing pigs. Currently is thought to be the result of a combined infection of Bordetella bronchiseptica and Pasteurella multocida types D andA.
  27. 27. Atrophic Rhinitis – UCVM, OI Top: Normal Right: Affected pig
  28. 28. The toxigenic strains of P.multocida produce cytotoxins which inhibit osteoblastic activity and promote osteoclastic reabsorption of the nasal turbinates. “The ventral scroll of the ventral nasal turbinate is the area most commonly and consistently affected”…
  29. 29. Inclusion Body Rhinitis – Porcine Cytomegalovirus (suid herpesvirus 2 [SHV-2]) infection, Pig, AVC, OI Usually in pigs 3-5 weeks of age. Fatal systemic infection occurs occasionally in younger suckling pigs (less than 3 weeks of age). Nasal submucosal glands with large basophilic Intranuclear inclusions (SHV-2).
  30. 30. Feline herpesvirus 1 (Feline viral rhinotracheitis [FVR]): rhinitis, conjunctivitis
  31. 31. Cat, vesicles, tongue – Feline calicivirus, Noah’s Arkives Morphologic Diagnosis?
  32. 32. Cat, feline calicivirus – ulcerative glossitis Noah’s Arkives
  33. 33. Feline Calicivirus (FCV). Mild oculonasal discharge in addition to vesicular and ulcerative stomatitis - diffuse interstitial pneumonia may also occur.
  34. 34. Cat, diffuse interstitial pneumonia, FCV.
  35. 35. Granulomatous rhinitis, dog due to Rhinosporidium seeberi (aquatic protistan parasite),TexasA&M University Mature sporangia filled with endospores
  36. 36. Guttural pouch tympany in a foal
  37. 37. Strangles, Streptococcus equi, lymph node and guttural pouch involvement
  38. 38.
  39. 39. Inflammation of the guttural pouch, horse (guttural pouch empyema) due to “strangles”-TAMU “Chondroids” “Inspissated” exudate
  40. 40.  Caused by infection with Aspergillus fumigatus or other Aspergillus species.  Involvement of cranial nerves (VII, IX, X, XI, XII) is common and result in a variety of clinical signs.  Erosion of the wall of the internal carotid artery can lead to epistaxis or fatal hemorrhage Guttural Pouch mycosis
  41. 41. Guttural pouch Mycosis- horse. Mdx? Multifocal, ulcerative and necrotizing eustachitis
  42. 42. Guttural pouch mycosis, horse
  43. 43. Guttural pouch mycosis, horse, AVC, Dr. A. Lopez.
  44. 44. Guttural pouch mycosis – AVC E24094-97, OI
  45. 45. Guttural pouch mycosis, AVC E24094-97 Which special stains are often used to visualize fungi within tissue sections? GMS (Gomori’s methenamine silver) stain and PAS (Periodic Acid Shiff) stain.
  46. 46. Nasal Squamous Cell Carcinoma, Cat
  47. 47. Nasal neoplasia Nasal carcinoma, 10 year-old dog,AVC
  48. 48. 3 year-old German Shepherd dog –Nasal and facial deformity, UCVM-09.
  49. 49. Nasal FSA, 3 year-old dog, UCVM.
  50. 50. Enzootic nasal carcinoma, sheep (retrovirus-induced).
  51. 51. Larynx  Necrotic laryngitis (Calf diphtheria) Secondary infection by Fusobacterium necrophorum following trauma or viral infection (IBR). Can also occurs as part of oral necrobacillosis in calves and swine. Plaques of ulceration covered by fibrinonecrotic exudate.
  52. 52. Larynx  Laryngeal hemiplegia (paralysis) – “roaring” horses.Atrophy of the left dorsal cricoarytenoid muscle.  Usually the result of an idiopathic neuropathy affecting the left recurrent laryngeal nerve. *From McGavin „s Pathologic Basis of Veterinary Disease book.
  53. 53. Trachea - bronchi  Tracheal collapse: Mainly in toy and miniature dog breeds; occasionally seen in horses, cattle and goats. Texas A&M
  54. 54. Dorso-ventral flattening of the trachea and concomitant widening of the dorsal tracheal membrane, pony May result in coughing and exercise intolerance.
  55. 55. UCVM-08, OI, feedlot heifer. Calf, Cornell files. IBR, Cattle Ulcerative and necrotizing laryngo-tracheitis
  56. 56. Canine infectious tracheobronchitis (Kennel cough).  A variety of infectious agents are often isolated from affected dogs but there is consensus that Bordetella bronchiseptica usually plays a primary role.  CAV-2, CPIV-2 and to a lesser extend canine distemper virus and Mycoplasma spp., have predisposing roles.
  57. 57. Horses and ponies– chronic bronchiolitis-emphysema complex, “heaves”, “broken wind”, Recurrent Airway Obstruction (RAO). Asthma-like syndrome (used to be known as Chronic Obstructive Pulmonary Disease (COPD) From: « Recurrent airway obstruction – heaves ». The Veterinary Clinics, Equine Practice, 19: 63-86, 2003. Renaud Léguillette, DMV, MSc, DACVIM. McGill University, UCVM- Canada. Severe heaves. The head &neck are extended and the horse shows nasal flaring with mucoid nasal discharge. „„Heave line.‟‟ The hypertrophy of external abdominal oblique muscles as a result of expiratory efforts suggests that the horse has been chronically affected by heaves.
  58. 58. Recurrent Airway Obstruction (RAO), Heaves.
  59. 59. RAO, horse, HE stained histo slide
  60. 60. Other similar disease in veterinary medicine : Feline asthma, a.k.a. feline allergic bronchitis. “Hyperactive airway disease”
  61. 61. Lungs  Blood-Air Barrier: Composed of the vascular endothelium, basement membrane of the endothelial cell, basement membrane of the type I pneumocyte and the cytoplasm of the of the type I pneumocyte.
  62. 62. Circulatory disturbances: Pulmonary haemorrhage  Exercise-induced pulmonary haemorrhage (EIPH): Relatively common condition in race horses.  Follows strenuous exercise.  Epistaxis is present in only 1-10% of affected horses.  Frequency increases with age and the severity of exertion.  Probably the result of marked elevations in arterial and capillary pressures during strenuous exercise.  Haemorrhage occurs in the dorso-caudal portions of the caudal lung lobes.  Massive pulmonary haemorrhage may be the only detectable lesion in horses that die during exercise .
  63. 63. Epistaxis and pulmonary hemorrhage are relatively common in cattle with vena cava thrombosis
  64. 64. * From McGavin’s Pathologic Basis of Veterinary Disease
  65. 65. Pulmonary edema, pig
  66. 66. Pulmonary edema, pig
  67. 67. Pulmonary edema Main pathogenic mechanisms: 1. ↑ hydrostatic pressure (cardiogenic edema). 2. ↑ vascular permeability: Injury to the blood-air barrier 3. Obstruction to lymphatic drainage: Neoplasia involving thoracic lymph nodes or vessels. Horse with CHF, UCVM, OI.
  68. 68. Pulmonary edema, horse, UCVM
  69. 69. HE-stain, dark brown pigment within the cytoplasm of alveolar macrophages, UCVM
  70. 70. Iron (Perl‟s) stain – Hemosiderin-laden macrophages (“heart failure cells”) within alveoli – UCVM.
  71. 71. From McGavin’s Pathologic Basis of Veterinary Disease Pigmentary disturbances: Pulmonary anthracosis
  72. 72. From McGavin’s Pathologic Basis of Veterinary Disease
  73. 73. Atelectasis  Incomplete expansion of the lungs or portions of the lungs.  Pulmonary parenchyma appears dark-red and sunken in comparison to aerated lung. Consistency is fleshy and the lung tissue does not float.  Congenital, acquired, compressive (caused by space- occupying lesions like hydrothorax, hemothorax, pleuritis), massive (pneumothorax).
  74. 74. Pulmonary atelectasis – bovine fetus; also in stillborn animals
  75. 75. Aspiration of amniotic fluid “Meconium is the dark-green mucilaginous material in the intestine of a full term fetus –a mixture of secretions from intestinal glands and amniotic fluid”
  76. 76. Patchy pulmonary atelectasis due to aspiration of meconium and amniotic fluid-calf, 1 day old,AVC.
  77. 77. Pulmonary Emphysema “Permanent enlargement of air-spaces distal to the terminal bronchiole, accompanied by destruction of alveolar walls”
  78. 78. Pulmonary Emphysema  Important primary disease in humans where often co-exists with COPD attributable to cigarette smoking.  “It is thought to be an imbalance between proteases and anti- proteases (like α1 antitrypsin) Neutrophil-derived serine proteases, particularly elastase and matrix metalloproteinases from a variety of sources are the likely culprits.Their concentrations are enhanced by neutrophil and macrophage activation induced in chronic bronchitis” –JKP, 2007 –G Maxie, ed.  The emphysematous lung is dysfunctional since the loss of alveolar septa reduced the alveolar surface area  Reduction in gas exchange.
  79. 79. Pulmonary Emphysema  In animals is always secondary to obstruction of outflow of air or agonal at slaughter.  Frequent in animals with bronchopneumonia airflow imbalance  the volume of air entering the lungs exceeds the volume exiting the lung during expiration.  Classified also as alveolar of interstitial (the latter mainly in cattle).
  80. 80.  Bullous emphysema: Large focal air-filled spaces (bullae) rupture may lead to fatal pneumothorax. Cow, pulmonary edema emphysema, ``fog fever``.
  81. 81. Bovine, interstitial emphysema
  82. 82. Pneumonia  No universal classification in veterinary medicine –quite confusing.  Right: Diagram of common patterns of pneumonia:  A: Normal lung  B: Suppurative bronchopneumonia  C: Fibrinous bronchopneumonia  D: Interstitial pneumonia  E: Embolic pneumonia  F: Granulomatous pneumonia A. Lopez, Atlantic Veterinary College Aerogenous (airborne) route and hematogenous route.
  83. 83. Pneumonias in cattle: Viral pneumonias  Infectious Bovine Rhinotracheitis (IBR): Caused by BoHV-1.  Para-influenza-3 virus (PI-3 virus) and Bovine Respiratory Syncytial virus (BRSV) cause a transient rhino-tracheitis and broncho-interstitial pneumonia with the formation of eosinophilic intracytoplasmic inclusions bodies in bronchial, bronchiolar and alveolar epithelial cells and alveolar macrophages. Formation of syncytial cells occurs in both, BRSV and PI-3 virus infection.  BRSV and PI-3 should be considered in calves with necrotizing bronchiolitis  Diagnosis is confirmed by virus isolation, PCR or detection of viral antigens by fluorescence antibody test (FAT) or immunohistochemistry (IHC).
  84. 84. BRSV-calf, AVC BRSV, heifer, Cornell files – Syncytial cells
  85. 85. BRSV. Right: IHC stains demonstrates widespread injury to the airway Epithelium.
  86. 86. Bovine enzootic pneumonia (chronic suppurative bronchopneumonia.  Disease caused by a variety of etiologic agents which include respiratory viruses, Mycoplasmas, Chlamydophila, followed by opportunistic bacteria such as Pasteurella multocida,Arcanobacterium pyogenes,Histophilus somni, Mannheimia haemolytica and E.coli. Calves with bovine leukocyte adhesion deficiency (BLAD), which prevents the migration of neutrophils from the capillaries, are highly susceptible to bronchopneumonia. Chronic suppurative bronchopneumonia, Calf, OVC.
  87. 87. Chronic suppurative bronchopneumonia, Calf, TS, OVC. Suppurative bronchopneumonia, calf, A. Lόpez, AVC.
  88. 88. Abscessation and bronchiectasis are Common sequels of chronic suppurative pneumonia.
  89. 89. Pneumonic mannheimiosis (“shipping fever”)  Acute respiratory disease that occurs in cattle several days or weeks after shipment.  Because Mannheimia haemolytica (formerly Pasteurella haemolytica) is typically isolated the term penumonic mannheimiosis or pneumonic pasteurellosis have been used.  Most economically important respiratory disease of cattle in NorthAmerica, particularly in feedlot cattle. Fibrinous bronchopneumonia, OVC.
  90. 90. Pneumonic mannheimiosis, steer, from McGavin.
  91. 91. Mannheimia haemolytica biotype A, serotype 1 is responsible for the severe pulmonary lesions (areas of necrosis etc.) Pneumonic mannheimiosis: Marbling appearance of the pulmonary parenchyma. What type of necrosis?
  92. 92. Respiratory histophilosis  Part of the Histophilus somni disease complex (TME, pneumonia, pleuritis, myocarditis, arthritis, abortion etc.,).  May cause suppurative or fibrinous bronchopneumonia. The later may be undistinguishable from the fibrinous bronchopneumonia caused by Mannheimia haemolytica. Fibrinous pneumonia, cattle-Cornell files
  93. 93. Mycoplasma bovis pneumonia  Important cause of chronic respiratory disease in feedlot cattle – common inAlberta.  The organism causes a chronic necrotizing bronchopneumonia which is quite characteristic.  M.bovis also causes severe chronic fibrinous arthritis. Chronic necrotizing bronchopneumonia, heifer, UCVM. Mycoplasma bovis was cultured from the lesions, OI, 2008.
  94. 94. Mycoplasma bovis
  95. 95. Necrotizing bronchopneumonia, heifer, UCVM, O.I., 2008. What type of necrosis?
  96. 96. Positive immunoperoxidase staining of M. bovis antigens, from McGavin‟s, 2012
  97. 97. Bovine tuberculosis Caused by M.bovis. It has been suggested that the termTB should be limited to diseases caused by M.tuberculosis (human) and M.bovis (cattle); other conditions should be referred as “Mycobacteriosis”. In NorthAmerica the disease has been almost eliminated but there still outbreaks that often originate from wild life (M.bovis not only affects cattle and humans but also deer, elk, bison etc. wild ruminants). Lesions are more common in retropharyngeal lymph nodes, lungs, thoracic and mesenteric lymph nodes. Lesions in cervids often contain prominent suppurative exudate and may resemble abscesses... Multifocal granulomatous pneumonia, M. bovis, cow, Dr. King-Cornell’s file.
  98. 98. Verminous bronchitis/ pneumonia In cattle is caused by infection with Dictyocaulus viviparus. Varies from interstitial pneumonia (larval migration) to chronic bronchitis (intrabronchial adult parasites) to granulomatous pneumonia (eggs, dead larvae). Cornell Files
  99. 99. Heifer, dictyocaulosis, OI, UCVM-2010 Dictyocaulus filaria –sheep, goats Dictyocaulus arnfieldi –equids (horses, donkeys)
  100. 100. Terminal bronchi from the right caudal lung lobe, pig. Slaughterhouse specimen, St. Kitts. Lung worms are admixed within slightly turbid mucoid exudate. Morphologic dx?.., etiologic dx?... Lung worms in pigs: Metastrongylus spp.
  101. 101. Numerous thin and elongated worms within the terminal bronchi of the caudal (diaphragmatic) lung lobes: Metastrongylus spp. Pig, slaughterhouse specimen, St. Kitts, 2012.
  102. 102. Same pig as in the previous image. Numerous Metastrongylus spp. are present within a bronchus, caudal lung lobe. Possible morphologic dx: catarrhal bronchitis; Etiologic dx: Verminous (or parasitic) bronchitis; pulmonary metastrongylosis. RUSVM, OI.
  103. 103. Atypical Interstitial Pneumonia (AIP) of cattle  Pneumonias that did not fit any of the “classical” forms of pneumonia  Characterized by the presence of edema, interstitial emphysema, hyaline membranes, type II pneumocyte hyperplasia and interstitial fibrosis with cellular infiltrates  These types of pneumonias have specific etiologies.  Investigators have proposed that these syndromes previously clustered underAIP be named according to their specific cause or pathogenesis.
  104. 104. Diffuse alveolar damage –formation of hyaline membranes – AIP, cow. From McGavin’s
  105. 105. Atypical Interstitial Pneumonias - common syndromes:  Bovine pulmonary edema & emphysema (“fog fever”)  Extrinsic allergic alveolitis (hypersensitivity pneumonitis)  Reinfection syndrome (hypersensitivity to Dictyocaulus sp. or BRSV).  Milk allergy: type I hypersensitivity in cows sensitized to their own milk casein and lactalbumin.  Ingestion of moldy potatoes  contain 4-ipomeanol which is metabolized by mixed function oxydases in the lung (Clara cells) to a potent pneumotoxicant.
  106. 106. “Fog Fever” Bovine pulmonary edema & emphysema (“fog fever”)  occurs in cattle grazing “fog” pastures (re- growth pasture after a hay or silage has been cut or lush green grass). L- tryptophan present in the pasture is metabolized in the rumen to 3- methylindole → absorbed into the blood and carried to the lungs → metabolized by the mixed function oxidases of non-ciliated bronchiolar epithelial cells (“Clara” cells) into a highly pneumotoxic compound that causes extensive necrosis of bronchiolar epithelial cells and type I pneumocytes (diffuse alveolar damage).
  107. 107. “Extrinsic Allergic Alveolitis” (hypersensitivity pneumonitis)  Common; mainly seen in adult dairy cows in the winter.The human counterpart is referred to as “farmer’s lungs”.  Type III hypersensitivity reaction to inhaled organic antigens, most commonly fungal spores present in moldy hay (local deposition of Ag- Ab complexes in the lungs).  Gross lesions vary from subtle gray subpleural foci of granulomatous inflammation to severe lesions in which the lungs acquire a “meaty appearance” due to alveolar epithelial hyperplasia, interstitial inflammation and fibrosis.
  108. 108. Pathogenesis of toxic and allergic pneumonias (“AIP”) in cattlle. * From McGavin’s pathology book
  109. 109. Pneumonias of Sheep Viral pneumonias: Like in cattle PI-3 virus and RSV can produce pneumonitis in sheep. Maedi (maedi-visna): Lifelong, persistent disease of sheep that occurs in most countries with the exception of Australia and New Zealand. It is also known as Ovine Progressive Pneumonia (OPP). The disease is caused by a retrovirus of the lentivirus subfamily (ovine lentivirus) similar to the agent of CAE. Infection results in a lymphocytic interstitial pneumonia (LIP). The virus may also cause a non-suppurative encephalitis (Visna), lymphocytic arthritis, lymphofollicular mastitis and vasculitis. Maedi is characterized by dyspnea and an insidious slowly progressive emaciation despite good appetite. In goats, CAE virus can cause a lymphocytic interstitial pneumonia similar to OPP in sheep.
  110. 110. Bacterial Pneumonias - Sheep Chronic enzootic pneumonia: Multifactorial disease –rarely fatal. In general it affects animals younger than 1-year-old. Etiologic agents include Mannheimia haemolytica, Pasteurella multocida,PI-3, adenovirus, reovirus, RSV, Chlamydophila, and Mycoplasmas (mycoplasma ovipneumoniae). Suppurative bronchopneumonia, sheep – Pasteurella multocida – from McGavin’s.
  111. 111.  Ovine pneumonic Mannheimosis: Similar to shipping fever in cattle.  Septicemic pasteurellosis: Caused by  Mannheimia haemolytica (biotypeA) usually in lambs under 3 months.  Bibersteinia (Pasteurella) trehalosi (biotypeT) usually in lambs 5 to 12 months-old. Lesions:necrotizing pharyngitis and tonsilitis, septicemia with disseminated intravascular thrombosis and bacteremia.
  112. 112. u Multifocal subpleural pneumonitis – Muellerius capillaris sheep, Cornell files Verminous bronchitis also occurs in sheep and goats. The etiologic agent Is Dictyocaulus filaria.
  113. 113. Pneumonias of horses Viral pneumonias: Equine viral rhinopneumonitis (EHV-1, EHV- 4) and equine influenza are important diseases in horses worldwide. In addition, equine viral arteritis (EVA) virus and equine adenovirus can also cause pneumonia in horses. These viruses often cause only a transient broncho-interstitial pneumonia but impair the pulmonary defences and make horses susceptible to secondary bacterial pneumonias (P.Multocida, Streptococcus spp.,E.coli,Klebsiella pneumoniae,Rhodococcus equi etc.). It has also been suggested that viral respiratory infections may predispose horses to “airway hyper-responsiveness” and “chronic obstructive respiratory disease” (COPD).
  114. 114. EquineViral Arteritis (EVA) virus – Arterivirus. Sporadic pansystemic disease of foals and horses: May result in interstitial pneumonia with vasculitis, pulmonary edema, hydrothorax and hydroperitoneum.
  115. 115.  Equine Morbillivirus (Hendra virus disease): Fatal respiratory disease in horses and humans (high mortality rates were seen in both horses and humans) which appeared in 1994 in Australia. Classified as a Morbillivirus, subfamily Paramyxoviridae.Affected horses have severely edematous lungs. Histologically there is vasculitis and the presence of multinucleated syncytial cells, typical of morbillivirus infections, in the endothelium of small pulmonary blood vessels and alveolar capillaries. No inclusion bodies are seen. Clinical signs are non-specific and include fever, anorexia, respiratory distress and nasal discharge
  116. 116. Interstitial pneumonia-foal, Equine Viral Rhinopneumonitis, Texas A&M, JE.
  117. 117. Interstitial pneumonia due to adenovirus or Pneumocystis carinii Infection are common complication in Arabian foals with SCID (Inherited disorder- autosomal recessive trait- characterized by lack of B and T lymphocytes  die before 5 months of age) Right: Pneumocystosis, Pig, AVC. Foamy eosinophilic proteinaceous material within alveoli. Fungal organisms are detected with Gomori’s methenamine silver stain (GMS). “Pneumocystosis is one of the most common and often fatal complications in AIDS patients”. Jack Russell Terrier
  118. 118. Adenovirus infection, foal, HE.
  119. 119. Interstitial pneumonia due to Pneumocystis carinii infection with concomitant Rhodococcus equi infection in a foal (Arabian CID foal).
  120. 120. Rhodococcus equi Important cause of morbidity and mortality in foals worldwide. Facultative intracellular gram positive bacterium that causes two major clinical syndromes. The organism may become enzootic in farms where the organisms has been shed earlier by affected foals. Virulence factors encoded by plasmids (virulence-associated proteins) appear to be responsible for the survival of the organism within macrophages (avoid phagocytosis by inducing defective phagosome-lysosome fusion). 6-week-old foal, Chronic pyogranulomatous pneumonia –Rhodococcus equi, Texas A&M University.
  121. 121. 6-week-old foal, Chronic pneumonia –Rhodococcus equi, Texas A&M University. Mdx: Pyogranulomatous pneumonia Cytokines, lysosomal enzymes and bacterial toxins are responsible for extensive caseous necrosis of the lungs and recruitment of large numbers of neutrophils, macrophages and giant cells containing numerous intracytoplasmic organisms. Affected foals develop chronic coughing and weight loss. “Any foal with bronchopneumonia unresponsive to routine broad-spectrum antibiotic therapy should be suspected of having R. equi bronchopneumonia” Equine practice, vol 14 (1): 15-18, 1992.
  122. 122. R.equi can infect people undergoing immunosuppression (AIDS, chemotherapy, therapeutically-induced immunosuppression because of organ transplantation).
  123. 123. Foal, Rhodococcus equi– Texas A&M pyogranulomatous enterocolitis/ lymphadenitis
  124. 124. Horse, idiopathic broncho-interstitial pneumonia. Note prominent Type II pneumocyte hyperplasia., HE
  125. 125. Horse, embolic Aspergillus infection (Mycotic pneumonia), Texas A&M, Dr. John Edwards. Multifocal, necrotizing and hemorrhagic (or necro-hemorrhagic) pneumonia
  126. 126. Pneumonias of pigs • Viral Pneumonias: Porcine reproductive and respiratory syndrome (PRRS): First recognized in Europe in 1987. PRRS is characterized by late-term abortions, stillbirths and respiratory disease in young pigs (interstitial pneumonia). Swine Influenza: Resulted from adaptation of the typeA influenza virus that caused the pandemic of human influenza duringWorldWar I. Low mortality unless complicated with secondary bacterial infections. H1N1 influenza pandemic in 2009. Postweaning multisystemic wasting syndrome (PMWS): Causes progressive emaciation in weaned pigs.The causative agent is PCV-2. May result in interstitial pneumonia. Porcine Respiratory Coronavirus (PRCV): Sporadic cause of mild bronchointerstitial pneumonia with necrotizing bronchiolitis.
  127. 127. Interstitial pneumonia, feeder pig – highly suggestive of viral pneumonia Right: Pneumocystosis, Pig, AVC. Foamy eosinophilic proteinaceous material within alveoli. Fungal organisms are detected with Gomori’s methenamine silver stain (GMS). Infections with Pneumocystis carinii are common in pigs with PRRS and PMWS.
  128. 128. Pig, enzootic pneumonia-Cornell. Multifactorial disease, Mycoplasma hyopneumoniae is the main pathogen involved. The organism induces a suppurative or cattarrhal bronchopneumonia with BALT hyperplasia that is quite characteristic. This highly contagious disease of pigs is influenced by immune status and management factors such as crowding, poor ventilation, humidity and temperature fluctuation in the barns. The disease is characterized by low mortality unless complicated with secondary pathogens.
  129. 129. Porcine Enzootic Pneumonia : Mycoplasma pneumonia (Mycoplasma hyopneumoniae, young piglet, UCVM, O.Illanes. Multifactorial disease.
  130. 130. Mycoplasma pneumonia, young piglet, UCVM, OI. The bronchopneumonia is mild to moderate (low mortality) unless complicated with Pasteurella multocida, Arcanobacterium pyogenes, Bordetella bronchyseptica, Haemophilus spp., Mycoplasma hyorhinis etc.).
  131. 131. 3-month-old pig, fibrinous pleuritis and pneumonia, may be a component of Glasser’s disease (Haemophilus parasuis) CVM, Western University of Health Sciences, O.Illanes
  132. 132. Porcine Contagious Pleuropneumonia, Actinobacillus pleuropneumoniae Highly contagious often fatal fibrinous bronchopneumonia of pigs 2-5 months of age. Dorsal area of the caudal lung lobes are often affected. Lesions are severe and characterized by hemorrhage, necrosis and thrombosis. Except for the distribution lesions are similar to those of pneumonic mannheimiosis of cattle. Cornell files
  133. 133. Porcine Contagious Pleuropneumonia, Actinobacillus pleuropneumoniae, CVM, Western University of Health Sciences, O.Illanes. Top: Cut surface, contagious pleuropneumonia, pig. Nebraska Diagnostic Laboratory – From McGavin‟s 2012.
  134. 134. Pneumonias of Dogs Pneumonias are not as common in dogs as in food- producing animals.  Infectious pneumonias: Infectious tracheobronchitis (Kennel cough) and canine distemper are the most common.  Non-infectious: Uremia and paraquat (widely used herbicide) toxicity are most common
  135. 135. • In addition to distemper, canine adenovirus type 2 (CAV-2), canine herpesvirus 1 (CHV-1) and canine influenza virus can produce pneumonias in dogs. • Bacterial pneumonias are often secondary to distemper virus infection or aspiration of gastric contents (when pulmonary defence mechanisms have been impaired). Pasteurella multocida,Streptococcus spp.,E.Coli,Klebsiella pneumoniae and Bordetella bronchiseptica can be involved.
  136. 136. Broncho-interstitial pneumonia, canine distemper From McGavin’s Path. Basis of Vet. Disease
  137. 137. Aspiration pneumonia, dog.
  138. 138. Granulomatous pneumonia, Blastomyces dermatitidis, dog -OVC
  139. 139. Dog, mycotic pneumonia (granulomatous pneumonia). Left: Blastomycosis, Bottom: Histoplasmosis McGavin’s –Path Basis of Disease
  140. 140. Uremic pneumonitis, dog.
  141. 141. Pneumonias of cats  Upper respiratory infections: Common  Pneumonias: Rare The viruses that produce upper respiratory disease may also induce pneumonia, but unless complicated with secondary bacterial infections they usually do not pose a significant clinical problem.
  142. 142. Cat, Dr. King, Cornell
  143. 143. Aelurostrongylus abstrusus Snails and slugs are the intermediate hosts. Subpleural nodules contain larvae and eggs, HE.
  144. 144. Pulmonary neoplasia  In comparison to humans primary pulmonary tumors are rare in animals  Most are malignant an appear as solitary masses of variable size  In domestic animals they are most common in dogs and cats.
  145. 145. Cat, pulmonary adenocarcinoma, HE.
  146. 146. Ovine pulmonary carcinoma (pulmonary adenomatosis). 3-year-old sheep, University of Zaragoza, Spain – in McGavin’s Caused by a transmissible retrovirus. Found around the world but not in New Zealand or Australia. Mainly seen in mature sheep. Slowly progressive signs of respiratory disease  death after several months from the initial onset of respiratory signs.
  147. 147. Metastatic neoplasms are relatively common. Primary pulmonary neoplasms, largely carcinomas are relatively rare but more common in aged dogs and cats.
  148. 148. Dog, Morphologic diagnosis? Cornell Files
  149. 149. Hydrothorax, 8-y-old dog, AVC From McGavin’s Path. Basis Of Vet. Disease Chronic liver disease (end-stage liver, cirrhosis). Pleura & pleural cavity
  150. 150. Hemothorax, dog with ruptured aortic aneurism.
  151. 151. Chylothorax, mink, WCVM
  152. 152. From McGavin’s Path. Basis Of Vet. Disease Fibrnous pleuritis, horse.
  153. 153. Pyothorax, Pasteurella Multocida, cat
  154. 154. Chronic pleuritis with “sulfur granules”, nocardiosis (Nocardia asteroides), Cat. From McGavin’s Path. Basis Of Vet. Disease
  155. 155. Mesothelioma – In domestic animals seen mainly in cattle – can be congenital. In humans has been associated with inhalation of asbestos (mining, construction, ship building).
  156. 156. Additional Information…
  157. 157. Fibrinosuppurative pleuropneumonia, rabbit –P. Multocida, Atlantic Veterinary College. Pasteurellosis is a common disease in domestic rabbits. P.multocida can result in rhinitis (“snuffles”), pneumonia, abscesses, reproductive tract infections, ear infections and septicemia.
  158. 158. Emu, AVC Mycotic airsacculitis – Aspergillus spp. infection
  159. 159. Emu, granulomatous pneumonia – Aspergillus, spp., AVC-1996
  160. 160. The End...