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An Overview of Poultry Pathology Part I. H. L. Shivaprasad California Animal Health and Food Safety Laboratory System, Tulare Branch University of California, Davis. California Animal Health & Food Safety Laboratory System. School of Veterinary Medicine University of California, Davis.
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An Overview of Poultry Pathology Part I H. L. Shivaprasad California Animal Health and Food Safety Laboratory System, Tulare Branch University of California, Davis
California Animal Health & Food Safety Laboratory System School of Veterinary MedicineUniversity of California, Davis To provide the citizens of California with the highest quality diagnostic laboratory support for: Mission
Disease Control Public health CAHFS Mission Health Management Food Safety Dissemination of New Knowledge Equine Health
Layers Broilers Turkeys CAHFS Laboratories Davis Turlock - Avian Tulare San Bernardino
Avian Taxonomy Phylum: Chordata Class: Aves Orders: 27 Families: 160 Genera: 1800 Species: 8600 Subspecies: >22,000
Major Categories of Birds • Domestic poultry (Egg laying and broiler chickens, turkeys and ducks) • Commercial and hobby/backyard flocks • Game birds (Pheasant, Quail, Chukar) • Pet and exotic birds • Ratites (ostrich, emu, rhea) • Birds of Prey • Birds in captivity (Zoos) • Free flying birds (California Fish & Game and National Wildlife Lab)
Segments of Poultry Industry (Broiler, turkey, egg layers) • Breeding – genetics • breeder replacements • Hatchery/custom hatching • Feed/feed mills • Housing – brooding/grow out (meat type) • Egg production • Processing (meat/eggs) • Transportation
Poultry Industry US/California • Eggs (Pullets/layers) – White Leghorn • Broilers/Fryers & Roasters (meat-type ) • White Plymouth Rock, White Cornish • Turkeys (Large White - Toms/Hens) • Ducks (Pekin/Muscovy/Mullard) • Pheasants (Ring necks: 18 - 20 weeks) • Squabs (500 g - 4 weeks) • Quail (meat/eggs), others?
Causes of Disease M: Malformation, Metabolic I : Infectious, Immunologic N: Neoplasia, Nutritional T: Toxic, Trauma Note: in commercial poultry infectious, nutritional and toxic causes are most important
Infectious • Bacteria • Viruses • Fungi • Parasites • Rickettsia
Tests Essential for Disease Diagnosis • History • Clinical signs • Necropsy (autopsy) • Serology (ELISA, HA/HI, AGID, etc.) • Immunology (FA, IHC, etc.) • Bacteriology/Mycology • Biotechnology
Tests Essential for Disease Diagnosis • Histopathology • Parasitology • Toxicology • Virology (egg embryos, cell culture) • Electron microscopy (DEM, TEM) • Hematology, chemistry, cytology • Pathogenicity tests
Diagnostic Protocol • Turn around time: • Report significant findings – same day • Serology, FA, IHC, bacteriology, biotechnology, Direct EM, histopathology – 12 to 48 to 72 hours • Toxicology - 3 to 5 days • Mycoplasma - 2 weeks • Virology - 3 to 6 weeks • IBV sequencing, TEM - variable
Disease Diagnoses - Philosophy • Quality: Accuracy of results • Rapid turn around time • Thorough diagnostic work up • Communication with the clients • Use of friendly, common and understandable language
Disease Diagnoses – Philosophy • Quality of service depends on the ‘quality and quantity of effort’ by the diagnostician/pathologist • sometimes it is difficult to find a cause • Client Confidentiality maintained
Avian Inflammation • reaction is rapid in birds, 36 hours • leakage of fibrin and fibrinogen common in early exudate • intense granulomatous reaction (12 hours) • coagulum of eosinophilic debris, degranulating heterophils, macrophages and giant cells
Avian Inflammation • macrophages, heterophils and thrombocytes are active phagocytes • pus is caseous but liquefaction can occur • birds respond with granulomatous inflammation to many insults
Avian Inflammation • acute inflammatory reaction in birds involves edema, congestion and vascular changes mediated by basophils and mast cells • 1-3 hrs: basophils, heterophils and monocytes • 2-6 hrs: basophils degranulate and die • 6-12 hours: lymphocytes, monocytes, macrophages
Avian Inflammation • 12-36 hours: lymphocytes, macrophages, giant cells • acute reaction peak by 12 hours (when giant cells appear) • 36-72 hours: regeneration and repair • fibroblasts, secondary lymphoid follicles, plasma cells • chronic reaction with caseation, macrophages, giant cells, granuloma formation
Avian Inflammation • Cells involved in inflammation: • Heterophils, mast cells, basophils, eosinophils • Thrombocytes • Monocytes/macrophages • Giant cells • Lymphocytes/plasma cells
Avian Inflammation • cells involved in inflammation: • heterophils: have lance-shaped granules, lack myeloperoxidase and alkaline phosphatase, have β-glucoronidase and acid phosphatase • very phagocytic • granules tend to round up in tissues, difficult to identify
Avian Inflammation • cells involved in inflammation (Cont.) • eosinophils: have spherical granules • function is not known, delayed type IV hypersensitivity ? • associated with eosinophilic enteritis in turkeys due to ascarids • basophils: contain histamine, involved in acute inflammation • thrombocytes: small round to oval cells with clear cytoplasm and small round nucleus (looks like small lymphocytes), phagocytic
Avian Inflammation • cells involved in inflammation (cont.) • monocytes: precursors to cells of MPS, phagocytic, can fuse to form multinucleated giant cells • Cytokines; IL-1, IL-2, IL-6, IL-8, IL-15, IL-18, etc., TNF, G-CSF, gamma interferon • lymphocytes: various morphologies involved in subacute inflammation including plasma cells
Fibrinosuppurative (heterophilic) inflammation – pericarditis, perihepatitis and airsacculitis
Fibrinosuppurative (heterophilic) cellulitis Fibrinosuppurative pneumonia Pus – liquefaction rare
Heterophils -(Lance-shaped granules) Heterophils and a eosinophil (arrow)
Eosinophilic enteritis, Ascarid larvae - Turkey Eosinophils – Turkey intestine
Granulomatous hepatitis (Yersinia pseudotuberculosis) Granulomatous inflammation
Fibrinous inflammation with bacteria. Gran. inflammation with Staphylococcus sp.
Avian Bacteria • E. coli • Salmonella sp. • Chlamydophila psittaci • Clostridia sp. • Mycobacteria sp. • Mycoplasma sp. • Bordetella avium • Pasteurella multocida • Gallibacterium anatis • Staphylococcus sp. • Streptococcus sp.
Avian Bacteria (Cont) • Enterococcus sp. • Ornithobacterium rhinotracheale • Erysipelothrix rhusiopathiae • Pseudomonas aeruginosa • Klebsiella pneumoniae • Riemerella anatipestifer • Avibacterium (Haemophilus) paragallinarum • Yersinia pseudotuberculosis • Spirochetes • Listeria, Neisseria-like • others
Colibacillosis • any one of the syndromes in poultry caused by E. coli • colisepticemia, air sac disease(CRD), peritonitis, coligranuloma, salpingitis, omphalitis/yolk sac infection, cellulitis, osteomyelitis/synovitis, swollen head syndrome and panophthalmitis • enteritis with AAEC, eae gene present • ceca most commonly involved • common in turkeys, others; chickens, pigeons, quail, partridges, pheasants, ducks, ostriches, psittacines, passerines, etc.
Omphalitis (yolk sac infection)
Fibrinous pericarditis, perihepatitis and airsacculitis Fibrinous pericarditis
Cellulitis Salpingitis
Avian Salmonellosis • A large group of acute or chronic diseases caused by one or more members of the genus Salmonella • Majority of salmonella are ubiquitous • Some are host specific • S. dublin in bovine, S. abortus equi in equine, S. choleraesuis in swine • S. Pullorum and S. Gallinarum in chicken
Avian Salmonellosis • Pullorum disease in poultry - S. Pullorum • Typhoid disease in poultry - S. Gallinarum • Paratyphoid in poultry, ducks, pigeons, wild birds, psittacines, passerines, etc. • 10-20 species; S. Typhimurium, S. Enteritidis, S. Heidelberg, S. Anatum, S. Derby, etc. • Arizonosis in turkey poults - S. arizonae • also in chicks, ducklings, psittacines, passerines, etc.