Biological characteristics of Vibrio harveyi causing hemorrhagic and ulcerative disease in barramundi cultured in Khanh Hoa

Abstract

Hemorrhagic and ulcerative disease is a common disease in barramundi in which vibrio is considered as one of the main causative agents. During the study on the causative agent of ulcer disease in barramundi cultured in cages at Van Ninh, Khanh Hoa, we screened potential pathogens and finally isolated Aus K0917 strain from the kidney of fish with ulcerated skin. This isolated strain was identified as V. harveyi by morphological characteristics and biochemical tests. The results of 16S rDNA gene sequencing of the isolate also showed 100% similarity with the sequence of Vibrio harveyi LS8 (accesstion FJ937878.1). The virulence of the Aus K0917 strain is quite high. The lethal dose of 50% of the barramundi population via intraperitoneal injection was determined to be 10^4.25cfu/fish within 8 days. Fourteen days after inoculation, V. harveyi could not be isolated from the surviving barramundi.

DOI: https://doi.org/10.53818/jfst.03.2022.69