Pathology of Fungal Diseases in Poultry.pptx

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1. Fungal Diseases in Poultry Disclaimer : This PPT only for the educational purpose Dr. Maneesh Jatav Assistant Professor

2. Syllabus Pathogenesis, gross and microscopic pathology od aspergillosis, thrush, favus, aflatoxicosis, ochratoxicosis , trichothecosis .

3. Avian Aspergillosis It is primarily a disease of the respiratory disease Etiology : A. fumigatous Aspergilli produce haemotoxin , neurotoxin and hepatotoxin A. fumigatous and A. flavus also produce an endotoxin Acute form in young birds – “ Brooder pneumonia ” Chronic form – in adult birds – Aspergillosis

4. Brooder Pneumonia Also known as 'brooder pneumonia ', aspergillosis is a disease of very young chicks . It is a disease of the respiratory system , and usually occurs when there are poor sanitary practices on the farm. Newly hatched chicks are highly susceptible to infection . Stress of cold, high ammonia, and dusty environments increase incidence and severity of the disease.

5. Etiology The disease is caused by a fungus called Aspergillus fumigatus . Contaminated poultry litter is usually the source of infection. Chicks become infected during hatching or during the first day or two in the brooder house, hence the name 'brooder pneumonia '.

6. Spread Infection occurs by inhalation of spores from contaminated feed or litter. A spore is that form of fungus which is very tough and resistant, and is therefore difficult to destroy. Fungal growth in wet litter produces large numbers of spores. These spores spread as suspended particles in air as wet litter dries

7. Symptoms The affected chicks may stop eating and show symptoms of gasping or labored breathing They breathe with an open mouth (gaspers ) due to obstruction of the airway Survivors may become dull and stunted , show sleepiness, lack of appetite, emaciation, increased thrust, develop eye swelling and torticollis (twisting of the neck to one side) Other birds may remain sub clinically affected for some time but they latter slowly develop breathing problems

8. Symptoms Infected poultry flocks usually show mortality in two phages Acute (sudden and severe ) respiratory disease – 5-50 % mortality in first 1-3 weeks of age Chronic stage – survivors with up to 5% mortality due to gradual loss of lung function, ascites, blindness or spread of fungus in nervous system

9. Clinical signs

10. Postmortem Findings Lesions found in the respiratory tract , including particularly the trachea, bronchi, lungs and air sacs Occasionally lesions are seen in the viscera, the eye and the brain The lungs are the main organ affected . They appear as white or pale yellow granulomatous, discrete small nodules of 1-9mm In some cases nodules are only a few, in others there may be hundreds. Nodules are also seen in the trachea and air sac Caseous exudate in the trachea Focal plaque on the surface of the brain and meninges In eyes fungal keratoconjuctivitis or panophthalmitis

11. Pm lesions

12. Diagnosis Aspergillosis is usually diagnosed at postmortem examination . Examination of the trachea or a cut lung will show nodules. This forms a basis for the diagnosis.

13. Treatment & Control Apart from providing adequate ventilation , there is no treatment for birds that are affected. A thorough cleaning of the brooding premises will eliminate the source of infection for future flocks. Any mouldy feed should be removed , feed containers cleaned, and old litter removed from the house and replaced with new. Drinkers and feeders should be cleaned and disinfected .

14. Aspergillosis Chronic form of disease is milder. Mortality is low and affected birds may survive for log period. The affected birds show similar symptoms as acute form but in milder form Anorexia, anaemia , yellowish of the feces, gasping, coughing, and presence od respiratory rattle. G ranumatous leisions are seen which either result from coalescence of many nodule

15. CANDIDIASIS (THRUSH) Fungal infection of digestive tract Caused by Candida albicans Also called “ moniliasis ” Fungus may cause infection of the mouth, esophagus or crop In crop is called “ Crop mycosis ”

16. Cause C. albicans usually present in the upper digestive tract of normal birds Predisposing factors : administration of antibiotics over a long period

17. Symptoms Birds with superficial infections of the mouth, esophagus or crop may fail to gain weight , remain stunted , show roughness of feather and become dehydrated In rare cases there is systemic invasion and symptoms of disease of nervous system, kidney, or intestine may be present

18. POST MORTEM FINDINGS Changes in crop are most common and consist of thickening of the lining of mucosa with formation of whitish circular, raised ulcer Crop is thickened by a soft, yellow-white to gray irregular false membrane It has curd like appearance and its surface tends to fall off in thin layers The mouth and esophagus show ulcer like patches If proventriculas involved, swollen, hemorrhagic and covered with inflammatory material

19. Lesions

20. DIAGNOSIS Demonstration of fungus under the microscope in either scrapings or tissue sections with confirm candidiasis Identification of the species requires culture on Sabouraud dextrose agar

21. CONTROL Controlling the use of antibiotics, and also controlling immunosuppressive diseases like Gumboro and CIA Strict observation of cleanliness and sanitation

22. Fowl Favus Chronic dermatophytosis of comb and wattles of domestic fowl. Also know as white comb . Main fungi involved : Trichphyton gallinae , T. simm and T. Metagrophyte . Young birds with well developed combs are more susceptible. Transmission : Through direct contact or through scales

23. Fowl FAVUS After infection, as the fungus spread, white powdery scaliness with concentric rings are seen on the combs and wattles. Scales may thicken and form crusts. Lesions may spreads to unfeathered portion of head. Fungus may also affect the upper parts of the respiratory and digestive tracts causing necrotic caseous lesions.

24. MYCOTOXICOSIS

25. Mycotoxins

26. Mycotoxicosis Known as mouldy feeds A large number of disorders in which disease or death is due to the invasion of fungi, or their products (toxins) produced by fungi in or on the animal’s feed. Collectively, these disorders are called “ mycotoxicosis ”

27. Aflatoxicosis Aflatoxin, Mycotoxin, Groundnut poisoning, Toxins of Aspergillus sp. Highly toxic and carcinogenic metabolites produced by fungi Aspergillus flavus and A. parasiticus Aflatoxins are produced when environmental conditions favour their growth At least 17 different aflatoxins exist The most important are B1, B2 , G1, G2 and M1

28. Aflatoxicosis The designations B and G refer to whether they f luoresce blue or green in UV light B1 is the most prevalent and most toxic Aflatoxin M1 , a mammalian metabolite of B1 , is execrated in milk The most commonly contaminated foods are groundnuts, maize, and cottonseed

29. Lesions: A number of factors influence the effect of aflatoxins Young birds are more susceptible than adults Poor nutritional status increases susceptibility Young turkeys and ducklings are much more susceptible than chickens The dose of aflatoxins and duration of exposure also influence of its toxicities

30. Development of disease Aflatoxins bind to nucleic acids and disrupts polyribosomes This leads interference with both nucleic acid and protein synthesis They also results in impaired T – cell function Decrease both antibody-mediated and cell mediated immunity Immunosuppression

31. Post-mortem findings Metabolic changes lead to liver, kidney, and spleen enlargement and a decrease in the size of busra of febricius , thymus and testes Liver is greatly enlarged, yellow and frible “ Bloody thigh syndrome” due to increased fragility of minute blood vessels

32. Lesion

33. Harmful effects Affects weight gain, feed intake, feed conversion efficiency, pigmentation, egg production, and male and female reproduction performance I mmunosuppression increased susceptibility to infectious disease Immunosuppression due to reduction in size of “ Bursa of Fabricius ” “ Lazy leukocyte syndrome ” : aflatoxin affects both number and activity of phagocytic cells

34. Clinical symptoms High level ( 10 ppm ) may cause death Decease growth Poor feed conversion Marked decrease in the resistance of birds to infections : immunosuppression Decreased egg production Reduced hatchability Reduced weights of testes and sperm count Level of aflatoxin B1 up to 0.38 ppm may be consider safe

35. Pathology Yellow discoloration of the liver, with multifocal hemorrhage Liver enlarged, friable and develop white foci as lipid content increases Microscopic, clear vacuoles in the cytoplasm of hepatocytes, karyomegaly, prominent nucleoli, proliferation of bile duct and fibrosis. Extramedullary hematopoiesis in the liver.

36. Pathology Causes anemia characterized by reduction in PCV, erythrocyte count, Hb conc. And MCV Young birds are more susceptible to anemia Aflatoxins also damages coagulation in chicken by interfering with several coagulation factors Petechial hemorrhages or bruises after trauma are increased due to deceased clotting factors synthesis and increased capillary fragility

37. Pathology In laying birds, aflatoxin blocks ova maturation and reduce feed efficiency and egg production Aflatoxins impairs egg production by reducing synthesis and transport of egg precursors in the liver Egg size, yolk wt. and yolk as percent of total egg size are decreased Toxin excreted in the bile and urine.

38. Diagnosis : Depend on the detection of afltoxin in the feed and blood serum, and the characteristic gross and histopathological findings in liver Detection of aflatoxins can be done in two ways 1. By biological testing 2. By chemical testing

39. OCHRATOXICOSIS Caused by the mycotoxin “ ochratoxin ” These produce by species of Aspergillus ochraceus Ochratoxin A is the most important toxin in natural poisonings in poultry Lesions restricted to the kidneys Ochratoxin is three times more harmful Also produce from Penicillium viridicatum A, B, C and D of these, ochratoxin A is the most toxic Young birds are more sensitive

40. Pm findings Produce degenerative changes In the kidneys Pasty white urate deposited on heart, liver and in joints

41. Symptoms Affected birds are depressed, dehydrated, usually pass more urine and die from renal failure Survivors are stunted growth, poor feathered and anemia and immunosuppression Reduced weight gain Laying hens may have delayed sexual maturity, deceased egg production and hatchability

42. Trichothecenes Group of highly toxic mycotoxins produced by several species of Fusarium and certain other fungi T-2 toxin , DAS (diacetoxyscirpenol ), vomitoxin (DON or deoxynivalenol) and satratoxin T2 and DAS are highly toxic Satratoxin produced by Stachybotrys sp. On ingestion cause a disease known as “ stabotryotoxicosis ” Cause immunosuppression

43. Other Mycotoxicoses Citrinine toxicosis : fungi Penicillium , damage kidney Oosporein : affect kidney, causing gaut and high mortality Moniliformin : fungus Fusarium moniliforme Fumonisins : fungus Fusarium moniliforme Fusarochromanone : Fusarium sp . Zearalenone : F-2 toxin Ergotism