First isolation and identification of Vibrio vulnificus (biotype 2) from cultured beluga, Huso huso in Iran

Abstract

By decreasing sturgeon stocks in the Caspian Sea, rearing different sturgeon species especially Huso huso was increased in Iran. Under stress conditions the sturgeon can easily be infected by several opportunistic pathogens. In June 2011, mortality happened in 25 - 28°C water temperature, in one of the most important cultured sturgeon farms in Mazandaran province, north of Iran. The mortality rate was 15%. The first clinical signs in moribund fish were lethargy and anorexia. A total of 20 moribund fish was transferred to a central laboratory for more bacteriological examination. Clinical signs including several deep ulcers on body surface, around the head, under operculum, ulcers at the base of the pectoral fins, hemorrhage around the anus, operculum, and pale gills were observed in moribund fish. The main internal signs were hepatomegaly and splenomegaly, liquid accumulation in the intestine and diffuse visceral hemorrhage. The results of morphology and microscopic characterizations and also biochemical tests indicated that Vibrio vulnificus (biotype 2) was the etiological agent of mortality in infected fish. This study was the first report of V. vulnificus in cultured H. huso in Iran.

Keywords

• Iran
• Huso huso
• first report
• Vibrio vulnificus