Animal Respiratory Diseases Lecture Notes PDF

SPECIES-SPECIFIC PNEUMONIAS HORSE  Viral Diseases Equine Viral Rhinopneumonitis Equine Multinodular Pulmonary Fibrosis Equine Influenza Adenovirus Equine Viral Arteritis  Equine viral rhinopneumonitis Definition: Acute respiratory disease in foals...

SPECIES-SPECIFIC PNEUMONIAS HORSE  Viral Diseases Equine Viral Rhinopneumonitis Equine Multinodular Pulmonary Fibrosis Equine Influenza Adenovirus Equine Viral Arteritis  Equine viral rhinopneumonitis Definition: Acute respiratory disease in foals (4 - 8 months) Cause: Equine herpes virus (EHV-1 and EHV-4) Forms: 1- Abortion (pregnant mare) 2- Respiratory 3- Nervous Respiratory form Bronchointerstitial pneumonia (non collapsing lung lobes, rib impressions)  Neurologic form Vasculitis Ischemia myeloencephalopathy  Aborted fetuses Multifocal area of necrosis in various organs (liver , lung)  Equine influenza Definition: Highly contagious respiratory disease of horses Cause: Influenza A virus (Orthomyxovirus)  High morbidity and low mortality (mild)  Secondary bacterial infections (Streptococcus equi)  Bacterial Disease Rhodococcus equi Burkholderia mallei  Rhodococcal pneumonia Definition: Granulomatous disease of foals Cause: Rhodococcus equi ( Corynebacterium equi)  Grossly Multiple, firm, nodules (containing caesous necrosis) pyogranulomatous lymphadenitis (Bronchial and mesenteric lymph nodes  Microscopically Pyogranulomatous pneumonia (granuloma contains neutrophils) CATTLE  Viral Diseases Infectious Bovine Rhinotracheitis (IBR) Bovine Respiratory Syncytial Virus (BRSV) Parainfluenza-3 virus. Bovine viral diarrhea virus Bovine coronavirus  Bacterial Disease Mannheimia haemolytica Pasteurella multocida, Hemophilus somnus Actinobacillus pyogenes Mycoplasma mycoides ssp. Mycoides Mycoplasma bovis Tuberculosis  Shipping fever Definition: acute respiratory diseases of cattle that occurred after shipment (Stress). Cause: Mannheimia haemolytica ( Pasteurella haemolytica) Grossly: (fibrinous bronchopneumonia) 1- Cranioventral hepatization (red and firm) 2- covered with yellow fibrin sheets 3- Hydrothorax 4- Marbling and mosaic appearance is due to : A- Multifocal necrosis B- interstitial edema  Contagious bovine pleuropneumonia Casus: Mycoplasma mycoides. Grossly:  similar to shipping fever  Mycoplasma bovis Bronchopneumonia, arthritis, otitis and mastitis. Grossly: multifocal nodules “caseous necrosis Histology : multifocal area of caseous necrosis surrounded by neutrophils  Enzootic Pneumonia of calves Multifactorial Disease Predisposed By Environmental Factors (Temperature, humidity, Poor Air Circulation, Crowding) Stress (Immune Status, Viral Infections) Bacteria  Tuberculosis  Zoonotic Granulomatous bacterial disease  Caused by acid-fast bacteria (bacilli):  Mycobacterium bovis (cattle)  Mycobacterium tuberculosis (human)  Mycobacterium avium (poultry)  Pathogenesis Inhalation of aerosol droplet or Ingestion of infected materials (milk) Bacteria phagocytized by alveolar macrophages Intracellular replication (Bacteria resistance to lysosomal hydrolases) Macrophage death and release of enzymes (caseous necrosis) Localize lymph node Hematogenous dissemination (bacteremia) seeding of multiple sites (generalized infection)  Gross Findings 1- Lung:  Firm, yellow-white nodules (tubercles)  Cut surface, Encapsulation, caseiation and calcification 2- Multifocal Tubercles on the pleura (Pearl disease) 3- Caseous nodules in tracheobronchial lymph nodes. 4- Multifocal nodules on all organ (liver, kidney, intestine, CNS, Vetebrae…) (Miliary T.B) Caseated nodules in lymph nodes Multifocal Tubercles (granuloma) on the pleura (pearl disease) (grape-like) Widely disseminated multifocal nodules on all organ (liver, kidney, intestine, CNS, Vetebrae…) (Miliary T.B)  Microscopic Findings Granulomas formation:  central areas of caseous necrosis & Calcification  surrounded by macrophages, lymphocytes, plasma cells + Langhans giant cells ( Large multinucleated cell, horse shoe shaped nuclei).  fibrous connective tissue  C) Giant cell (C) central areas of caseous necrosis  Additional Diagnostic Tests: Tuberculin test (Antemortem) PCR Special stains: Acid-fast ( Ziehl-Nielson) Culture Sheep and Goats  Viral Diseases Ovine Adenovirus Respiratory Syncytial Virus Lymphoid Interstitial Pneumonia (Maedi) Caprine Arthritis Encephalitis (CAE) Peste Des Petits Ruminants Sheep pox  Bacterial Disease Mannheimia haemolytica Pasteurella multocida, Hemophilus somnus Mycoplasma ssp Caseous lymphadenitis  Parasitic Disease Muellerius capillaris Characteristic finding subpleural nodules in dorsal region of caudal lung lobes  Hydatid cyst Intermediate stage of Echinococcus granulosus (tape worm)  Dog Canine influenza Canine adenovirus Canine distemper Canine herpesvirus  Canine Distemper, Highly contagious disease of young dogs Morbillivirus (paramyxoviridae) Multisystemic disease: 1. Conjunctivitis 2. Rhinitis 3. Bronchointerstitial Pneumonia 4. Enteritis 5. Skin: Parakeratosis (Paws) 6. Encephalitis.  Cat Feline Calicivirus Feline Rhinotracheitis Feline Infectious Peritonitis (FIP)  Pleuritis ( Pleurecy) It is the inflammation of the pleura.  Abnormal contents in the pleura Pneumothorax : Accumulation of gases within the thoracic cavity Hemothorax: hemorrhage within thoracic cavity Chylothorax : the accumulation of chylous fluid (lymph) in a thoracic cavity. Hydrothorax: Accumulation of clear fluid within the thoracic cavity Pyothorax : Accumulation of pus within thoracic cavity A cytologic smear from a dog with chylothorax. The nucleated cells consist of well-preserved neutrophils (A), macrophages (B), medium to large lymphocytes (C), and large numbers of small lymphocytes (D). Cytology smear from a feline pyothorax. Neutrophiles mixed with bacteria  Lung and Pleural Tumors Relatively rare in animals compared to human beings. More common in dogs and cats. Metastatic sarcoma According to cell line: 1. Epithelial (adenoma or carcinoma). 2. Mesenchymal fibroma or fibrosarcoma hemangioma or hemangiosarcoma Primary or Secondary (Metastatic)  Ovine pulmonary adenocarcinoma Pulmonary adenomatosis Contagious retroviral of sheep Fluid drains from nostrils when the head is lowered multifocal small, firm, gray nodules