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Created page with "Also known as: '''''Winter Fungus''''' ==Introduction== This term describes infection with fungi of the ''Saprolegnia'' complex. Some of the species are primary pathogens wherea..."
Also known as: '''''Winter Fungus'''''
==Introduction==
This term describes infection with fungi of the ''Saprolegnia'' complex. Some of the species are primary pathogens whereas others only cause disease only when there is '''preexisting illness''', mechanical injury or environmental stress.
''Saprolegnia'' filaments are long with rounded ends, containing the zoospores.
''Saprolegnia'' can also infect '''fish eggs''', establishing itself first on dead ones and then extending to neighbouring healthy ones.
A significant component of the pathogenesis is the action of the distinctive recurved attachment hairs which may function like burrs.
Factors which may be involved in the development of saprolegniasis include '''traumatic damage to the skin''', concurrent infections and '''low water temperatures'''.
==Clinical Signs==
''Saprolegnia'' lesions are '''focal grey-white patches''' on the skin which have a '''cotton wool-like''' appearance under water when the hyphal elements extend out. The early lesions are circular and extend out until they merge.
The patches can then become '''dark grey or brown''' as the mycelium traps mud or debris.
The '''head''' region is most commonly involved, but any part of the skin or gills, even internal organs, can be affected.
'''Respiratory distress''' may be evident if the gills are involved, and '''death''' can follow rapidly.
==Diagnosis==
The clinical signs are quite characteristic.
'''Skin scrapes''' examined under the microscope may help identify the fungal hyphae which belong to ''Saprolegnia''.
'''Histopathology''' reveals: the fungus invading the stratum spongiosum of the dermis and then the epidermis, causing erosions as it spreads. Numerous hyphae will be seen, and underneath, dermal necrosis and oedema. There is also a slight inflammatory response.
==Treatment and Control==
A variety of chemical treatments can be used to control the infection, such as '''malachite green, copper sulphate, potassium permanganate, salt and formalin'''.
Prevention involves maintaining fish under '''good husbandry conditions''', by correcting nutrition, ensuring good water quality and avoiding overcrowding.
Even so, fish may still succumb from the disease.
{{Learning
|flashcards = [[Ornamental Fish Q&A 14]]
}}
==References==
Roberts, R. (2001) '''Fish Pathology''' ''Elsevier Health Sciences''
Durborow, R. (2003) '''Saprolegniasis (Winter Fungus) and Branchiomycosis of Commercially Cultured Channel Catfish''' ''Southern Regional Aquaculture Center Publication''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]
==Introduction==
This term describes infection with fungi of the ''Saprolegnia'' complex. Some of the species are primary pathogens whereas others only cause disease only when there is '''preexisting illness''', mechanical injury or environmental stress.
''Saprolegnia'' filaments are long with rounded ends, containing the zoospores.
''Saprolegnia'' can also infect '''fish eggs''', establishing itself first on dead ones and then extending to neighbouring healthy ones.
A significant component of the pathogenesis is the action of the distinctive recurved attachment hairs which may function like burrs.
Factors which may be involved in the development of saprolegniasis include '''traumatic damage to the skin''', concurrent infections and '''low water temperatures'''.
==Clinical Signs==
''Saprolegnia'' lesions are '''focal grey-white patches''' on the skin which have a '''cotton wool-like''' appearance under water when the hyphal elements extend out. The early lesions are circular and extend out until they merge.
The patches can then become '''dark grey or brown''' as the mycelium traps mud or debris.
The '''head''' region is most commonly involved, but any part of the skin or gills, even internal organs, can be affected.
'''Respiratory distress''' may be evident if the gills are involved, and '''death''' can follow rapidly.
==Diagnosis==
The clinical signs are quite characteristic.
'''Skin scrapes''' examined under the microscope may help identify the fungal hyphae which belong to ''Saprolegnia''.
'''Histopathology''' reveals: the fungus invading the stratum spongiosum of the dermis and then the epidermis, causing erosions as it spreads. Numerous hyphae will be seen, and underneath, dermal necrosis and oedema. There is also a slight inflammatory response.
==Treatment and Control==
A variety of chemical treatments can be used to control the infection, such as '''malachite green, copper sulphate, potassium permanganate, salt and formalin'''.
Prevention involves maintaining fish under '''good husbandry conditions''', by correcting nutrition, ensuring good water quality and avoiding overcrowding.
Even so, fish may still succumb from the disease.
{{Learning
|flashcards = [[Ornamental Fish Q&A 14]]
}}
==References==
Roberts, R. (2001) '''Fish Pathology''' ''Elsevier Health Sciences''
Durborow, R. (2003) '''Saprolegniasis (Winter Fungus) and Branchiomycosis of Commercially Cultured Channel Catfish''' ''Southern Regional Aquaculture Center Publication''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]