GAA: Cause of EMS identified
After months of research by a team at the University of Arizona, the Global Aquaculture Alliance on Wednesday identified the pathogen causing early mortality syndrome (EMS) in farmed shrimp.
The researchers found that EMS is caused by a bacterial agent, which is transmitted orally, colonizes the shrimp gastrointestinal tract and produces a toxin that causes tissue destruction and dysfunction of the shrimp digestive organ known as the hepatopancreas. It does not affect humans.
GAA said research continues on the development of diagnostic tests for rapid detection of the EMS/AHPNS pathogen that will enable improved management of hatcheries and ponds, and help lead to a long-term solution for the disease. It will also enable a better evaluation of risks associated with importation of frozen shrimp or other products from countries affected by EMS.
Some countries have implemented policies that restrict the importation of frozen shrimp or other products from EMS-affected countries. The researchers frozen shrimp likely pose a low risk for contamination of wild shrimp or the environment because EMS-infected shrimp are typically very small and do not enter international commerce. Also, repeated attempts to transmit the disease using frozen tissue were unsuccessful.
Since EMS was first reported in China in 2009, it has spread to Vietnam, Malaysia and Thailand, and now causes annual losses more than USD 1 billion. EMS outbreaks typically occur within the first 30 days after stocking a newly prepared shrimp pond, and mortality can exceed 70 percent.