Technical Information
Early mortality syndrome (EMS) and acute hepatopancreatic necrosis (AHPND) are different
Since its first appearance in 2009, acute liver necrosis disease (AHPND) has caused great losses to shrimp farms worldwide. However, there is confusion when equating the concept of early mortality syndrome (EMS) with acute hepatopancreatic necrosis disease (AHPND).
EMS was named by Asian shrimp farmers circa 2009 to describe an unexplained premature mortality syndrome in shrimp that causes high mortality in their ponds between 30 and 30 years. First 40 days of rearing. It is not called a disease but a syndrome because it is a collection of signs and symptoms that often appear without knowing the cause, causing shrimp to die very quickly after stocking.
By mid-2011, Lightner et al. identified a new histopathological marker in some EMS shrimp characterized by sloughing of hepatopancreatic tubule epithelial cells, hence the term necrosis syndrome. Acute liver death (AHPNS) and then in 2013 Dr. Tran Huu Loc and colleagues discovered strains of Vibrio parahaemolyticus as the causative agent of AHPNS. The name of the disease was later changed to acute hepatic necrosis disease (AHPND).
Vibrio parahaemolyticus strains, contain a virulent plasmid containing the virulence genes pirA and B (pirAB). Recently, AHPND was reported to be caused by other Vibrio species such as Vibrio harveyi, Vibrio campbellii and Vibrio owensii, which were also found to contain virulent plasmids resembling the pirAB of V. parahaemolyticus (Han, Tang, Aranguren) , & Piamsomboon, 2017 ; Xiao et al., 2017).
White leg shrimp suffering from acute hepatopancreatic necrosis disease caused by Vibrio owensii carrying virulence genes AHPND causes high mortality in shrimp ponds, but its occurrence is too high to be equated with EMS. A study (Sanguanrut et al., 2018) was conducted in Thailand from August 19, 2013 to April 23, 2014 on 200 shrimp ponds randomly selected before stocking in endemic areas. early mortality (EMS). The overall disease occurrence rate for the EMS ponds in this study was 16.3% but only 56% of these EMS ponds were diagnosed with AHPND. This shows that early mortality syndrome in shrimp has many causes and AHPND is just one of them. For this reason, it is important to diagnose the cause of death in EMS ponds and not equate it with AHPND. See the English version at: Journal of the World Aquaculture Society, Anuphap Prachumwat, Suparat Taengchaiyaphum, Natthinee Mungkongwongsiri, Diva J. Aldama-Cano, Timothy W. Flegel and Kallya Sritunyalucksana
