Development of PCR Diagnosis for Shrimp Acute Hepatopancreatic Necrosis Disease (AHPND) Strain of Vibrio parahaemolyticus

Acute hepatopancreatic necrosis disease (AHPND) is caused by a unique strain of Vibrio parahaemolyticus that has a plasmid harboring virulent genes. A rapid and accurate diagnosis method is necessary for surveillance of this infectious disease in aquaculture. In this study, three primer sets (TUMSAT-Vp1, Vp2 and Vp3) were designed based on the plasmid DNA sequence. We examined 98 strains of bacteria isolated from shrimp farms in different areas in Thailand. These included 48 strains of V. parahaemolyticus (AHPND strain), 38 strains of non-AHPND V. parahaemolyticus and 12 strains of non-V. parahaemolyticus. All the AHPND strains were detected by TUMSAT-Vp1, Vp2 and Vp3. However, one non-AHPND strain tested positive for TUMSAT-Vp1 and Vp2. The accuracy of AHPND detection was validated with two other primer publicly available sets (AP1 and AP2). AP1 and AP2 primers gave a few false positives in non-AHPND strains. Only TUMSAT-Vp3 primer detected the AHPND strains examined in this study with 100% accuracy.