Epizootic ulcerative syndrome

Epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis (MG) or red spot disease (RSD), is a disease caused by the water mold Aphanomyces invadans . It infects many freshwater and brackish fish species in the Asia-Pacific region and Australia . The disease is most commonly seen in tropical and sub-tropical waters.

Clinical signs and diagnosis

At first, fish develop red spots on the skin. These lesions expand to form ulcers and extensive erosions filled with necrotic tissue and mycelium . This is followed by the development of granulomas on the internal organs and death.

A provisional diagnosis can be made by using squash preparations of the skeletal muscle from beneath an ulcer to identify the hyphae septate of the water mold. Definitive diagnosis can be based on histopathological findings and isolation of the pathogen.

Treatment and control

Infected fish should be moved to high quality water, where they can recover if their clinical signs are mild.

If disease occurs eradication is required. Once the disease is eradicated Good husbandry , monitoring and biosecurity Measures are Necessary to prevent prevention recurrence. In countries free of epizootic ulcerative syndrome, quarantine and health certificates are necessary for the movement of all animals to prevent the introduction of the disease.


  • Epizootic Ulcerative Syndrome, reviewed and published by Wikivet at http://en.wikivet.net/Epizootic_Ulcerative_Syndrome , accessed 08/09/2011.

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