Mr Anwar Hasan, Regional Technical Manager – Aquaculture, Biomin Singapore Pte Ltd, Singapore
Every few years, we discover the emergence of new diseases in shrimp farming in Asia. In the past, most of the very damaging diseases in shrimp were caused by viral pathogens, but now we find that natural bacterial and microsporidian/fungi are major pathogens. The most devastating disease in recent years that has affected shrimp production is the acute hepatopancreatic necrosis disease (AHPND) or often known as early mortality syndrome (EMS), which brought down shrimp production in Thailand, China, Malaysia and Vietnam by more than 50%. The white faeces disease (WFD) and Enterocytozoon hepatopenaei (EHP) are also emerging threats to shrimp production. WFD can be found in almost all shrimp-farming countries in Asia, including Indonesia, where shrimp farming has significantly been affected.
Amongst current viral diseases, white spot disease (WSD) poses as a major threat in almost all Asian countries, mostly occurring during the rainy season. In India, WSD is the main disease problem. The infectious myonecrosis disease (IMND), meanwhile, is only found in Indonesia and it has become even more virulent than it was a few years ago, resulting in mortality rates of up to 80%. In several Asian countries, shrimp diseases with similar symptoms as IMND that are also causing high mortality, have been discovered, but this has turned out to be negative IMNV. Several nodaviruses could be the suspect.
The challenges with disease differ in each country and the strategies adopted at the farm level also vary. This presentation will share updates from countries such as India, Thailand, Vietnam and Indonesia with regard to production and the current state of shrimp diseases. Farmers have been facing a dilemma as they look to deploy various strategies to manage these diseases and to better understand the pathogens present in the farm environment. This makes managing trigger points especially important to managing the impact of diseases.