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Poultry Respiratory Diseases: Overview and Pathology Details

Learn about infectious bronchitis, laryngotracheitis, Newcastle disease, avian influenza, and their impact on poultry health. Detailed histopathological features and viral variations are discussed.

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Poultry Respiratory Diseases: Overview and Pathology Details

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  1. An Overview of Poultry Pathology Part II H. L. Shivaprasad California Animal Health and Food Safety Laboratory System, Tulare Branch University of California, Davis

  2. Infectious laryngotracheitis • acute viral respiratory disease of primarily chickens • pheasants and peafowl are also susceptible • etiology: herpesvirus (field and vaccine) • lesions: oculonasal discharge, trachea with hemorrhage and/or fibrinous exudate • conjunctivitis, sinusitis, laryngitis, tracheitis and bronchitis, airsacculitis, etc. • syncytia formation and intranuclear inclusion bodies – not always found

  3. Infectious Laryngeo Tracheitis (ILT- Herpesvirus) – chicken

  4. Infectious LaryngotracheitisHistopathology • Lymphoplasmacytic inflammation • syncytia with intranuclear inclusions • Numbers and size • Conjunctiva (cornea), third eye-lid • Sinus/turbinates • Larynx, trachea, syrinx • Bronchi, parabronchi • Air sacs

  5. ILT, chicken trachea – Syncytia with inclusions

  6. Infectious Bronchitis • highly contagious viral respiratory disease of young chickens • egg production and quality problems in layers • etiology: coronavirus, many serotypes, great antigenic variation in strains of virus • lesions: catarrhal tracheitis, conjunctivitis, bronchitis, airsacculitis • fibrinosuppurative inflammation in cases complicated with E. coli • interstitial nephritis with nephrotropic strains

  7. Infectious Bronchitis Virus Antigenic variation • Genetic drift/shift - RNA viruses are less stable than DNA viruses • Genetic recombination between different serotypes • Genetic changes often occur in the hyper- variable regions of the S1 gene – codes for the virus spike protein

  8. Infectious BronchitisPathology • Increased mucus in the trachea, nasal passages, sinuses • Complications with E. coli very common • Swollen sinuses/swollen head, airsacculitis associated with yellow caseous exudate • Bronchitis in chicks • Nephritis/gout/urolithiasis due to nephropathogenic strains • Atrophy of the oviduct and ovary • Proventriculitis (China), myositis (UK)

  9. IBV, chicken trachea – Increased mucus

  10. Infectious Bronchitis (IBV - Coronavirus)) – bronchitis, chicken IBV – nephrosis, chicken

  11. IBV - Tracheitis, Nephrosis/nephritis

  12. Newcastle Disease • Acute viral disease of many species of birds • 236 species of birds comprising 27 orders • Etiology: Avian Paramyxovirus –1 • Isolates vary greatly in pathogenecity to chickens • Lentogenic: mild or inapparent respiratory infection • Mesogenic: disease and mortality • Velogenic: lethal infection of all ages • Called Exotic Newcastle Disease (END) in US • OIE Classification: > 0.7 Intra Cerebral Pathogenecity Index (ICPI) are END/NDV (Pigeons – exception?) • < 0.7 ICPI are APMV-1

  13. Newcastle disease (NDV- Avian Paramyxovirus -1) Hemorrhagic conjunctivitis, chicken NDV – Hemorrhagic conjunctivitis

  14. NDV, chicken - oral cavity, esophagus and larynx NDV, chicken – larynx and trachea

  15. NDV, chicken - proventriculus

  16. NDV, chicken - intestines

  17. NDV, chicken – cecal tonsils, ceca, colon

  18. NDV, chicken – colon and cloaca

  19. Avian Influenza • Caused by type A Avian Influenza (AI) virus, Orthomyxovirus • AI viruses are divided in to subtypes • based on Haemagglutinin (H) and Neuraminidase (N) antigens • 16 H (H1 – H16) and 9 N (N1 – N9) distinct types, all found in avian species • H1 N1, H5 N1, H7 N2, H6 N2, etc. • Novel H1 N1 of 2009/2010 – causes drop in egg production in poultry

  20. Flu Pandemics in Humans • 1918 - 19 (Spanish Flu) – H1 N1 • 1957 - 58 (Asian Flu) - H2 N2 • 1968 - 69 (Hong Kong Flu) - H3 N2 • 1977 - H1N1 • 1997 - Hong Kong, H5 N1 • 2003 - China/Hong Kong, H5 N1 • 2004 - Present. S.E. Asia, china and others, H5 N1 • 2009 – present. H1N1

  21. Bird Flu (H5N1) • Acute systemic lethal disease of poultry caused by H5 N1 subtype • Migratory waterfowl are the primary reservoirs • pigs also serve as reservoirs • H5N1 infections in >40 countries since December 2003 • >500 million birds depopulated • Approximately 385 people (240 fatal) • All human infections a result of direct contact with birds

  22. Transmission & Host Adaptation of Influenza A Viruses • Most Common: Intraspecies, e.g. human-to- human, pig-to-pig, chicken- to-chicken, etc. • Occasional: Interspecies & intraclass, e.g. pig-to- human, wild-mallard-to-domestic turkey, etc. • Recently, but rarely: Interspecies & interclass, e.g. bird-to-human, bird-to-pig, • Conclusion: Influenza viruses express host adaptation to various levels Dr. Swayne

  23. Bird Flu • Significance: virus could evolve in to a form that is easily spread between people • How: human flu virus and bird flu virus could recombine producing a hybrid • Transmission to humans: direct contact with chickens and their secretions • Outbreak: has spread rapidly to various countries in poultry • Control: kill infected poultry, anti flu drugs, vaccination?

  24. Avian Influenza – H5N1 • 1997 Hong Kong • 2003 -2004 South East Asia (China, Korea, Vietnam, Indonesia, Thailand, Japan, Cambodia, Laos, Malaysia) • 2005 (Russia, Kazakhstan, Mongolia, Romania, Turkey, Croatia) • 2006 – 2010 more than 40 countries including India

  25. Bird Flu - Species Susceptible • Gallinaceous birds; chickens, turkeys, quail, pheasants, partridges • Zebra finches (*), geese, emus, House finches, budgerigars, ostriches • Ducks, gulls, swans, starlings, pigeons • Egrets, herons, flamingos, magpie, falcon, owl, sparrow, etc. • Mammals; humans, tigers, leopards, cats, civets, pigs, ferrets

  26. AI/Bird Flu - Transmission • Contact • Respiratory secretions • Feces • Contaminated feed and water • Carcasses • Equipment, fomites (shoes, clothes, hands, etc.) • others

  27. Avian Influenza - Pathogenecity • Varies with the strain (H5 and H7) • High (HPAI) or low path (LPAI) ? • HPAI can arise from LPAI circulating in birds • Presence of concurrent infections • Age and species of birds, nutritional and environmental factors • Definition of HPAI • Intravenous Pathogenecity Index (IVPI): > 1.2 (lethal for 75 % of chickens) • Amino acid sequence at the Haemagglutinincleavage site compatible with HPAI

  28. Low Pathogenic AI - Pathology • Secondary bacterial infections common • Sinusitis, rhinitis, conjunctivitis • Airsacculitis, tracheitis, pneumonia • Peritonitis, edema of oviduct • Enlarged kidneys with urates • Hemorrhage and regressive ovary

  29. Avian Influenza (AI) – turkey, sinusitis LPAI (H9N2) – turkey, sinusitis Differential Diagnoses – MG, TRT (metapneumovirus), etc.

  30. LPAI–turkey. Pneumonia (top) and airsacculitis (right)

  31. LPAI (H4N6)-Chicken. Peritonitis

  32. LPAI (H1N1)-Turkey. Attretic follicles, ovary

  33. Highly Pathogenic (H5 and H7) AI - Pathology • Similar to NDV • Swollen comb/wattle, head and legs • Sinusitis/rhinitis, subcutaneous edema/hemorrhages • Subcutaneous hemorrhages, legs • Pulmonary edema and congestion • Hemorrhages in internal organs • trachea, heart, proventriculus, intestine, etc. • Slides courtesy of Dr. David Swayne, SEPRL

  34. Edematous to necrotic comb/wattle Subcutaneous hemorrhage of shanks Highly Pathogenic Avian Influenza • Edema of head and legs Poultry FAD 2005

  35. Highly Pathogenic Avian Influenza • Pulmonary edema, congestion and hemorrhage • Visceral hemorrhage Poultry FAD 2005

  36. Avian Encephalomyelitis • Disease of chickens caused by Picornavirus • Turkeys, quail and pheasants are susceptible • Neurological signs (epidemic tremor, ataxia) in young chicks and egg production drop in layers • Gross Pathology – none (may be pale areas in the muscular layer of gizzard) • Micro: Non suppurative encephalomyelitis – central chromatolysis of neurons. Lymphoid nodules in muscular layers of proventriculus and gizzard, pancreatitis, myocarditis, myositis, etc. • Cataracts in some survivors

  37. Avian Encephalomyelitis (AE), chicken - brain

  38. AE – chicken. Gizzard (gross) Proventriculus (histopath) AE - cataract

  39. Avian Pox • Slow spreading viral disease of chickens, turkeys, quail, pigeons, canaries, raptors, psittacines, ostrich, peacock, waterfowl • 60 species of wild birds • Etiology: poxvirus of genus Avipoxvirus, many strains • fowl pox, turkey pox, pigeon pox, canary pox, quail, mynah, psittacine, junco, sparrow, starling, etc. • Signs: cutaneous, respiratory, digestive, ocular • septicemic form in canaries, 70 - 90% mortality

  40. Pox – chicken, turkey and pheasant

  41. Pox – Chicken. Oral cavity, larynx and skin. Pox - quail

  42. Fowl Pox – chicken Proliferative tracheitis Fowl Pox – Intracytoplasmic inclusion bodies

  43. Infectious Bursal disease (IBD) • acute viral disease of young chickens(1- 6 wks) and secondary immunosuppression • etiology: Birnavirus • lesions: enlarged and edematous bursa of Fabricius some times with hemorrhages • atrophy of bursa in later stages • Hemorrhage in bursa with very virulent IBD • lymphoid necrosis and depletion, secondary infections such IBH, bacteria, cryptosporidia

  44. Infectious Bursal Disease (IBD – Birnavirus) – chicken, bursa of Fabricius, normal on left. Bursa of Fabricius – Petechiae due to IBDV

  45. Bursa of Fabricius with necrosis and hemorrhage due to very virulent IBDV Courtesy – anonymous, Peru

  46. Bursa of Fabricius – Normal (top) Lymphoid depletion & edema due to IBDV

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