Changes

It has been reported primarily in '''Europe''' and Taiwan but also in the southeast USA.

It has been reported primarily in '''Europe''' and Taiwan but also in the southeast USA.

The two most commonly isolated species are ''B. sanguinis'' and ''B. denigrans'' which have different host specificities and distributions.

The two most commonly isolated species are ''Branchiomyces sanguinis'' and ''B. denigrans'' which have different host specificities and distributions.

The organism attaches to the gill surface and '''forms hyphae''' which penetrate the tissue and damage the blood supply to the area. '''Spores''' can be released and develop on the floor of the tank in favourable conditions (35-32°C, low oxygen, lox pH).

The organism attaches to the gill surface and '''forms hyphae''' which penetrate the tissue and damage the blood supply to the area. '''Spores''' can be released and develop on the floor of the tank in favourable conditions (25-32°C, low oxygen, low pH).

==Clinical Signs==

==Clinical Signs==

Infected fish exhibit '''respiratory symptoms''' and a loss of equilibrium.

Infected fish exhibit '''respiratory symptoms''' and a loss of equilibrium. The gill appears '''necrotic, eroded and pale'''.

'''Mortalities''' can occur in less than 48 hours and can reach 50% of the herd.

 

'''Mortalities''' can occur in less than 48hours and can reach 50% of the herd.

==Diagnosis==

==Diagnosis==

'''Wet mounts or histopathology''' of the lesions will enable a diagnosis to be made. Characteristic hyphae within the vessels of the gills or penetrating the gill tissue will be visible. These hyphae are light brown, slightly refractile, branching and non-septate.

'''Wet mounts or histopathology''' of the lesions will enable a diagnosis to be made. Characteristic hyphae within the vessels of the gills or penetrating the gill tissue will be visible. These hyphae are light brown, slightly refractile, branching and non-septate.

'''Special stains''' such as the GMS can be used to identify the fungal elements.

'''Special stains''' such as the Gomori methenamine silver (GMS) can be used to identify the fungal elements.

''B. denigrans'' appears to affect the entire gill whilst ''B. sanguinis'' is restricted to gill blood vessels.

''B. denigrans'' appears to affect the entire gill whilst ''B. sanguinis'' is restricted to gill blood vessels.

There is '''no known treatment''' for the disease but some protocols may be beneficial with malachite green, formalin baths, copper sulphate and benzalkonium chloride dips, and oral methylene blue.

There is '''no known treatment''' for the disease but some protocols may be beneficial with malachite green, formalin baths, copper sulphate and benzalkonium chloride dips, and oral methylene blue.

'''Predisposing factors''' to help control the condition include reducing overcrowding, levels of ammonia, algal blooms, levels of organic material, water temperature and improving hygiene.

'''Factors''' that help control the condition include reducing overcrowding, levels of ammonia, algal blooms, levels of organic material, water temperature and improving hygiene.

Infected or dead fish should be promptly removed from the tank, pH in the tank can be increased by adding quick lime, and ponds can be drained and limed.

Infected or dead fish should be promptly removed from the tank, pH in the tank can be increased by adding quick lime, and ponds can be drained and limed.

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[[Category:Fish Diseases]]

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