Progress in research on acute hepatopancreatic necrosis disease (AHPND)

Abstract

Acute hepatopancreatic necrosis disease (AHPND) of shrimps is an important disease, first appeared in China in 2009. Since then, AHPND has caused serious drops in shrimp production (up to 20 % worldwide). Although AHPND [originally termed as acute hepatopancreatic necrosis syndrome (AHPNS)] first appeared in 2009, it was not until 2013 that a laboratory infection model was devised and the causative agent identified as certain strains of Vibrio parahaemolyticus. AHPND has caused mortality from 40 to 100 % which usually occurs early (within approximately 35 days) after stocking shrimp fry in shrimp ponds; therefore, it was initially referred to as early mortality syndrome (EMS). Confusingly, other pathogens and environmental factors also cause EMS and are often attributed to AHPND by shrimp farmers. Frequently, farmers do not send samples for confirmatory tests requiring detection of the unique histopathology at the acute stage of disease (massive sloughing of hepatopancreatic epithelial cells without any accompanying signs of a pathogen). The gross signs presumptive of AHPND (lethargy, slow growth, empty stomach and midgut, and a pale to white, atrophied hepatopancreas) are insufficient for confirmatory diagnosis. Recently, molecular detection of AHPND bacteria using PCR has been developed, which has sped up diagnosis and increased research on the causative agent, alternative detection methods, and possible therapies. We hope that this review of research progress on AHPND will serve as a useful introduction for researchers who are currently unfamiliar with AHPND, but have backgrounds in bacterial virulence, detection, and epidemiology, and may be encouraged to participate in the research effort to reduce AHPND’s impact on shrimp cultivation.