June 1, 2012

An emerging shrimp disease known as early mortality syndrome (EMS)/acute hepato-pancreatic necrosis syndrome (AHPNS) has been reported to affect shrimp farmers in China, Vietnam, Malaysia and Thailand, according to the Network of Aquaculture Centres in Asia-Pacific (NACA).

The disease affects both P. monodon and P. vannamei and is characterised by mass mortalities (reaching up to 100% in some cases) during the first 20-30 days of culture (poststocking in grow-out ponds).

This degenerative pathology of hepato-pancreas is highly suggestive of a toxic etiology, but anecdotal information suggests that disease spread patterns may be consistent with an infectious agent. The primary cause/pathogen (considering the disease is infectious) has not been identified yet.

Considering the likely threat of great economic loss that EMS will cause in the region's shrimp industry, concerted action by every shrimp producing country in the region is urgently required to prevent the spread and/or occurrence of this disease. Farmers, on the other hand, should be made aware of this threat and requested to cooperate with the concerned agencies by promptly reporting any suspected mortalities among cultured shrimp that appear to be similar to the clinical description of EMS/AHPNS.

As a first step, NACA is widely disseminating a Disease Advisory to Competent Authorities (CA) and concerned stakeholders in member governments urging improved surveillance and reporting efforts on the part of all stakeholders including farmers. Only through surveillance, early response, and contingency planning and disease preparedness can countries minimise the impact of the impending threat.

Considering the potential severity and impact of the emerging threat, NACA is prepared to convene a regional consultation of CAs or their representatives from affected and other potentially vulnerable countries in Bangkok at the earliest possible time to develop practical contingency plans.