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| − | Also known as: '''''Focal Tuberculosis in fish -- Piscine Mycobacteriosis -- Piscine Tubercle -- Chronic Inflammatory Foci (CIF) -- Tubercle Granuloma'''''
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| − | ==Introduction==
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| − | ''Mycobacteria'' infect many species of '''freshwater, saltwater''' and '''aquarium fish'''. The latter species are more likely to show a higher incidence of disease due to the chronicity of the disease and increased ages of aquarium kept fish compared to commercial fish.
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| − | Some ''mycobacteria'' found in fish species are '''zoonotic''' and '''''M. marinum''''' and '''''M. fortuitum''''', can cause '''skin disease in humans'''. Outbreaks have been reported from '''cutaneous abrasions''' and '''exposure to contaminated swimming pool water'''. ''M. fortuitum'' has been cultured from patients with pulmonary disease and local abscesses <ref name="Cruz, 1938">Cruz, J.C., (1938) '''Mycobacterium fortuitum um Novo Bacilo Acidoresistente Patogenico para o Homen.''' ''Acta Medical Rio de Janeiro'', 1:297.</ref> and ''M. chelonei'' has been isolated from heterograph heart-valve transplants, synovial fluid and muscle <ref name="Blacklock and Dawson, 1979">Blacklock, Z.M., Dawson, D.J., (1979) '''Atypical mycobacteria causing nonpulmonary disease in Queenland.''' ''Pathology'', 11:283-288.</ref><ref name="Thoen and Schliesser, 1984">Thoen, C.O., Schliesser, T.A., (1984) '''Mycobacterial infections in cold-blooded animals.''' In: Kubica GP, Wayne LG, eds. ''The Mycobacteria: A Sourcebook Part B''. New York, USA: Marcel Dekker, 1297-1311.</ref>.
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| − | ==Signalment==
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| − | The disease has been reported in '''many species of fish''' as well as '''''Penaeidae'' (prawn spp)''' and '''sea horses'''. Outbreaks have been reported in salmon, cod, halibut, bass, mackerel, turbot, trout, morays, silversides, tilapia and perch. Pond dwelling species such as pejerrey and snakehead fish and freshwater aquarium fish such as the Siamese fighting fish, Goldfish, Eight-banded cichlid, Zebrafish, Neon tetra, and Labyrinth fish.
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| − | The '''severity''' of the disease has been '''linked to age''' and disease outbreaks can be linked to '''nutrient and water quality''' and '''quantity, stress''' and '''stocking density'''.
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| − | ==Clinical Signs==
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| − | Clinical signs consist of '''haemorrhagic lesions, erosion and scale loss on skin and fins''', enlarged organs, lordosis, cachexia, exophthalmia, '''loss of pigmentation''', and '''pale and cystic gills'''. Behavioural signs include '''cessation of feeding, lethargy''', and '''swimming near the surface'''.
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| − | ==Epidemiology==
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| − | Fish may be '''infected by ingesting feed and water contaminated with faecal material, urine or exudates from diseased animals''' that contain mycobacteria<ref name="Ross and Johnson, 1962">Ross, A.J., Johnson, H.E., (1962) '''Studies of transmission of mycobacterial infections of chinook salmon.''' ''Progressive Fish Culturist'', 24:147-149.</ref>. The identification of ''Mycobacteria'' and acid-fast bacteria in piscine ova and tubercle granulomas in ovaries of different species suggests that transovarian transmission may be a possibility.
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| − | Mycobacteriosis can be '''sub divided''' into '''subacute''' and '''chronic forms''' and once fish are infected, mycobacteria spread via the circulatory or lymphatic system to other organs such as the '''spleen, kidney and liver'''. Both hard and soft granulomas are formed in the chronic proliferative form and in severe cases larger granulomas form within visceral organs and loose connective tissues. ''Mycobacterium'' has many '''vectors''' including '''crustaceans and molluscs'''.
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| − | ==Distribution==
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| − | '''Worldwide''' - ''Mycobacterium'' is '''ubiquitous in the water and sediment'''. It has been documented in fish from the Atlantic and Pacific Sea, Asia, Africa, North America, Australia, South America and Europe.
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| − | ==Pathology==
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| − | Pathology includes '''necrotised and enlarged spleen, kidney and liver''' with '''diffuse greyish-white nodules''', cysts (white spheres) within the body cavity and muscle, fusion of visceral membranes and increased peritoneal fluid.
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| − | Histopathology of granulomas varies for subacute and chronic forms.
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| − | :'''Sub acute forms''' have a '''large caseous necrotic areas''' with '''surrounding diffuse reticuloendothelial cells and macrophages'''. Acid-fast bacilli can be found within the reticuloendothelial cells and within the cytoplasm of phagocytic macrophages.
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| − | :Whereas the '''chronic proliferative form''' is characterized by '''soft granulomas with four distinguishable layers'''; a '''central caseous necrosis''', (with or without nuclear debris), '''spindle-shaped epithelioid cells''', '''eosinophilic, flattened, epithelioid cells''' and then a '''fine fibrous connective tissue''' encircling to form a thin capsule. '''Hard granulomas''' can also been seen with '''chronic forms''' and are composed of '''epithelioid cells encapsulated by fibrous connective tissue with or without calcification'''.
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| − | Infected crustaceans show melanised lesions in muscle, cuticle, ovary, gill and heart.
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| − | ==Diagnosis==
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| − | Mycobacteriosis can be '''confirmed''' by '''PCR, DNA probes-in situ hybridisation''' and '''antibody-based methods''' and presumptive diagnosis can be made from clinical signs, bacteriology and histopathology.
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| − | ==Treatment==
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| − | '''Tetracycline and kanamycin sulphate''' can be used to treat mycobactriosis and experimentally cotrimoxazole, cycoserine, ethambutol, isoniazid, rifampacin and streptomycin have been used.
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| − | {{Learning
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| − | |flashcards = [[Mycobacteriosis - Fish Flashcards|Mycobacteriosis in Fish Flashcards]]
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| − | ==References==
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| − | <references/>
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| − | {{CABI source
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| − | |datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=74501&loadmodule=datasheet&page=2144&site=160 mycobacteriosis in fish]
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| − | |date =10 July 2011
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| − | }}
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| − | <br><br><br>
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| − | {{review}}
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| − | {{OpenPages}}
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| − | [[Category:Fish Diseases]] | |
| − | [[Category:Zoonoses]]
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| − | [[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
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