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An Overview of Poultry Pathology Part II

An Overview of Poultry Pathology Part II. H. L. Shivaprasad California Animal Health and Food Safety Laboratory System, Tulare Branch University of California, Davis. Infectious laryngotracheitis. acute viral respiratory disease of primarily chickens

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An Overview of Poultry Pathology Part II

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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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