Respiratory diseases in poultry are common in commercial flocks and cause great economic loss to farmer. Major respiratory diseases of chicken are discussed briefly here with some uniqueness

1. Respiratory Diseases of
Chicken
MuhammadArslan Musa
M.Sc.(Hons.)Poultry Science
arslan2062@gmail.com

2. Respiratory Diseases
Bacterial Viral Fungal
CRD IB Aspergillosis
InfectiousCoryza ILT
ND

3. Causative Agents
CRD Mycoplasma gallisepticum
IC Avibacterium paragallinarum
ND Paramyxo virus-I
IB Corona virus
ILT Tarpeia avium
Aspergillosis Aspergillus fumigatus

4. Mortality
Mortality (%)
CRD 30
IC 5-20
ND 50-100
IB 25-30
ILT 10-20
Aspergillosis 5-50

5. Disease Duration
Duration (weeks)
CRD Weeks to months
IC 2-3
ND 2
IB 2
ILT 2-4
Aspergillosis

6. Vertical Transmission
CRD Yes
IC No
ND No
IB No
ILT No
Aspergillosis No

7. Occurrence before3 weeks of age
CRD Rare
IC Rare
ND Yes
IB Yes
ILT Rare
Aspergillosis Yes

8. Mortalityafter 3 Weeks
CRD Usually low with many culls
IC Very low with many culls
ND 0-5
IB 0
ILT 50
Aspergillosis

9. Nasal and Ocular Discharge
CRD Yes
IC Yes (catarrhal)
ND Yes (sticky)
IB Yes
ILT Nasal
Aspergillosis

10. Facial Signs
CRD Facial edema
IC S/C edema of face and wattles
ND Mild edema of face and neck
IB No
ILT No
Aspergillosis No

11. Tracheal Lesions
CRD Mucus in trachea
IC Tracheitis
ND Hemorrhages and congestion of trachea
IB Serous, catarrhal or caseous exudate or plugs of pus trachea
ILT Blood stained mucus and hemorrhages in trachea
Aspergillosis White to pale yellow and hard nodules and or creamcolored plaques

12. Lungs
CRD Cheesy materialin lungs
IC No
ND No
IB No
ILT No
Aspergillosis White to pale yellow andhard nodules andor cream
coloredplaques

13. Air Sacs
CRD Cloudy airsacs
IC -
ND Cloudy airsacs, thickening of walls ofair sacs
IB Cloudy airsacs with yellow exudate
ILT -
Aspergillosis White to pale yellow andhard nodules andor cream
coloredplaques

14. Effecton Egg Production
Drop in Egg production
CRD 10-20% for one month
IC 10-40% but may reachup to 70%
ND Cessation egg production within few days
IB 10-50% (poor eggquality)
ILT 1-20 %
Aspergillosis
-

15. Easy to Differentiate
CRD Swollen face, foamyair sacs
IC Pus in respiratory tract
ND Nervoussigns, pin point hemorrhagesin proventriculus
IB Plugs in trachea, misshapen or shell-less eggs, urate deposition in
kidney
ILT Expectoration of bloody mucus
Aspergillosis White to pale yellow and hard nodules on lungs, trachea and air sacs

16. Treatment
CRD Tylocin+ Doxycycline,Tiamulin,Tilmicosin,Spectinomycin
IC Tylocin+ Doxycycline,Erythromycine
ND Supportive Therapy
IB Supportive Therapy
ILT Supportive Therapy
Aspergillosis Nystatin

17. Chronic Respiratory
Disease (CRD)

18. Transmission of Mycoplasmosis

19. Pathogenesis

20. Clinical Signs
• Respiratory rales
• Conjunctivitis
• Nasal discharge
• Coughing
• Gasping
• Reduce feedconsumption
• Decrease body weight
• Decrease in eggproduction
• Carcass downgrading and condemnation

21. Postmortem Lesions
• Mucous in trachea
• Air-sacculitis
• Pericarditis
• Perihepatitis
• Cheesy materialin lungs
• Paleand flabby muscle

22. Treatment
• Tylosin, tilmicosin, tiamulin,spectinomycinand tetracyclines are very effectiveagainst
mycoplasma but not remains so mucheffectiveif secondary E.coli infectionis present
• Enrofloxacin is effectiveagainstboth mycoplasma and E.coli
• Tetracycline and chlortetracycline althoughhave dual action but antibiotics resistance is
present in E.coliagainstthesedrugs

23. Facial Edema Sticky eyelids and nasal discharge

24. Tracheitis with mucus Mild Tracheitis

25. Air-sacculitis with caseous exudate Mild foamy Air-sacculitis

26. Infectious
Coryza

27. • Caused by Avibacterium paragallinarum
• Disease of upper respiratory tract
• Mostly hit thebirds of 5-30 weeks of age
• Incubationperiod is 1-3 days
• Disease duration 2-3 weeks
• Caused 10-40 % drop inegg production

28. Transmission of Disease
• No vertical transmission
• Horizontal transmissionis mainlythroughthe
• - Fecal-oral route
• - Air
• - Carrier birds

29. Pre-Disposing Factors
• Concurrent Infection(CRD, E. coli, Fowlcholera, IBD, IB and ILT)
• Highaltitude
• Fall or winter season

30. Clinical Signs
• Strong smell similar to rotten eggs
• Nasal and ocular discharge
• Facial swelling
• Sneezing
• Difficultbreathing
• Conjunctivitis
• Swollenwattles(particularly in malebirds)
• Severe decrease in egg production (normally 10-40% butcan reach up to 70%)

31. Nasal Discharge Nasal Discharge

32. Edema of face Difficult Breathing

33. Post Mortem Lesions
• S/C edema of face and wattles
• Catarrhal inflammationofsinuses and nasal passages
• Tracheitis

34. Newcastle Disease(ND)
• Affect all poultry birds
• Incubationperiod ranges 2-15 days however usually it is 5-6 days
• Zoonotic disease
• Depends upon immunestatus, concurrent infection, virus strain and age of bird
• Up to 100% but in mild type infectionit is 50% or more

35. Clinical Signs
• Greenish diarrhea
• Stickynasaland ocular discharge
• Difficult breathing and Voice production
• Ocular and nasaldischarge
• Torticollis
• Paralysisof legs and wings
• Backward movement of bird
• Cessation egg production within few days (for several weeks)
• Soft shelled or shell-lesseggs, deformed eggs (only few eggs)

36. Postmortem Lesions
• Pinpoint hemorrhages in proventriculus
• Hemorrhages on caecal tonsilsand intestinalmucosa
• Hemorrhagic trachea
• Cloudy air sacs and thickeningof wall of air sacs
• Hemorrhages inlower conjunctiva

37. Torticollis Mild edema of face and neck

38. Conjunctivitis + ocular discharge Leg Paralysis

39. Edema and Hemorrhages
Hemorrhages in proventriculus

40. Trachea

41. Infectious Bronchitis
• Causedby Corona virus (Group 3)
• This virus can replicatein thecellcytoplasm,respiratory system,digestivetract (fecal-oral
route)and reproductive system
• Vaccinalvirus can persist ininternalorgans upto163days or evenmore
• Incubationperiodis 18-36hours

42. Clinical Signs
• Coughing,sneezing, gasping and tracheal rales (i.e. gurgling
• Watery nasal and ocular discharge (very rare in adultbirds)
• Severe decrease egg production (10-50%)
• Thinor soft shelled,rough shelled or misshapen eggs and watery albumin

43. Postmortem Lesions
• Serous, catarrhal or caseous exudate in sinuses, nares and trachea
• Mucoid plugs of pus inlower trachea (cause asphyxia)
• Foamy and cloudy air sacs with yellow exudate(acute form)
• Paleand swollen kidney (Nephropathogenic)
• Urate deposition in ureters

44. Gasping Dyspnea

45. Labored breathing ( severe case) Tearing

46. Edema and congestion of trachea Mild exudate in trachea

47. white caseous exudate in the syrinx
and primary bronchi Swollen Kidneys and urate deposition

48. Infectious Laryngotracheitis (ILT)
• First vaccine in poultry was developed againstILT
• Incubationperiod is 6-12 days
• Morbidity is 90-100%
• Mortality varies 5-70% butnormal range is 10-20%
• In mild form, morbidity is up to 5% and mortality is 1-2%

49. Clinical Signs
• Expectoration of blood stained mucus
• Nasal dischargeand watery eyes
• Respiratory rales
• Coughingand Gasping (Loud)
• Conjunctivitis

50. Post Mortem Lesions
• Blood stainedmucus in trachea
• Hemorrhages intrachea
• Hemorrhages in laryngeal tissues

51. Dyspnea
Expectoration of bloody mucus

52. Trachea ILT infected Vs Norma tracheal lumen

53. Aspergillosis
• Disease of young chicks butmay affect older birds
• Immunosuppression, cold weatherammoniaand dust influencedisease
occurrence

54. Clinical Signs and Postmortem Lesions
• Difficultbreathing
• Inhibitionof feed intake
• Whiteto pale yellow and hard nodules on lungs, trachea and air sacs