(fis.com) Thai researchers have developed a new method for detecting isolates of the bacteria that cause acute hepatopancreatic necrosis disease (AHPND), or commonly known as early mortal syndrome (EMS).
In December 2013, a group of Thai and Taiwanese scientists released information on the primers and PCR protocols to bacteria causing this disease responsible of extensive damage to both domestic and international shrimp industries.
Despite the success attained with these protocols, named AP1 and AP2, the Thai research team continued to study this disease and make improvement on the detection technique.
The National Center for Genetic Engineering and Biotechnology (BIOTEC) informed that on 18 June, at the 6th International Shrimp Industry Development Forum at Zhanjiang Guangdong, China, the research team released information on a new and improved PCR method, called AP3 method.
This method is based on the gene sequence of a protein discovered in a sub-fraction of cell-free culture broth from isolates of Vibrio parahaemolyticus that cause AHPND, but not from V. parahaemolyticus or other bacteria that do not cause AHPND.
This cell-free preparation caused the typical signs of acute AHPND (massive sloughing of hepatopancreatic tubule epithelial cells) when administered to shrimp by reverse gavage. Primer (AP3) was designed to amplify the gene sequence of one small protein from this toxic sub-fraction.
According to BIOTEC, the AP3 method gave 100 per cent sensitivity, specificity, positive predictive value and negative predictive value for the detection of AHPND bacteria using 98 bacterial isolates characterized by bioassay as AHPND and non-AHPND bacteria.
The AP3 method was developed by a consortium of scientists from Mahidol University, Aquatic Animal Health Research Center of Charoen Pokphand Company and BIOTEC.