Vibrio sp. associated with acute hepatopancreatic necrosis disease (AHPND) found in penaeid shrimp pond from east cost of peninsular Malaysia

Abstract

Aim: Acute hepatopancreatic necrosis disease (AHPND) is one of the fastest emerging disease in shrimp aquaculture industry. Based on a recent AHPND case reported in our local shrimp farm, this study aimed to isolate, identify and characterize the causal agent of AHPND isolated from a shrimp farm located in Malaysia. Methodology : The isolates were first screened with AP4 primers, then identified based on phenotypic observations and phylogenetic analysis. Screening of selected virulence genes, antibiotic susceptibility test, and virulency study of the isolates using Artemia sp. as challenge model were carried out to further distinguish each isolates. Results : Six positive AHPND isolates were reported in this study, where four of them were identified as V. harveyi and another two were V. parahaemolyticus. All the isolates appeared to be susceptible against tetracycline. V. parahaemolyticus (C2A, C4B) showed higher virulency than V. harveyi (CIB, C2B, C4A, D5) when tested in Artemia sp. challenge study. Interpretation : This study reports that, in Malaysia, both V. parahaemolyticus and V. harveyi could be the causative pathogen of AHPND outbreak in local shrimp farm.