Detection methods of Acute Hepatopancreatic Necrosis Disease (AHPND) and its mutant (mutant-AHPND) in shrimp

Abstract

Acute Hepatopancreatic Necrosis Disease (AHPND) is a globally serious threat, especially for Vietnam shrimp culture since its first discovery in China in 2009. This disease is caused by toxin-carrying bacteria Vibrio parahaemolyticus whose plasmid encodes for a binary toxin ToxA and ToxB. The disease has a mortality rate of up to 100% after 3 - 5 days post-infection and fast spread among shrimp culturing regions. In 2017, a bacterial strain V. parahaemolyticus XN87 containing plasmid with mutant toxA and normal toxB genes was found. In this mutant form, shrimp did not show hepatopancreatic necrosis symptoms, but the early mortality rate in shrimp was still up to 50%. This mutation was called mutantAHPND. Depending on different purposes and subjects, the corresponding detection method will be selected. Understanding the specific nature and application of each method is essential for the prevention and treatment of AHPND disease in shrimp to minimize economic losses for shrimp farmers. In this review, we summarized AHPND-detected methods based on detecting genes (toxA and toxB) or protein (ToxA and/or ToxB toxins) as well as a method for early detection of the mutant-AHPND. Eventually, potential detection methods are also addressed and discussed.